SSC Pacific
New in AREPS 
 
What's new in AREPS

AREPS 3.6 has formally received a Navy and Marine Corps Intranet (NMCI) "Certified - Ready to Deploy" for Windows XP operating systems. As a consequence, within the Department of the Navy, Chief Information Officer, Department of the Navy Applications Database Management System (DADMS), AREPS version 3.2.1 is now disapproved for use.

The current version of AREPS is 3.6.50.38 dated 30 November, 2010. The following are the new features and modifications to the previous version (3.6.50.37 dated 22 November, 2010). The pre-beta version is not yet available. See pre-beta version 3.7.04.40 dated 30 April, 2009 below.

The "Yearly Statistics" tab under the Upper Air Climatology option in the Environment Creation program was not being displayed properly. This has been corrected.


The current version of AREPS is 3.6.50.37 dated 22 November, 2010. The following are the new features and modifications to the previous version (3.6.50.33 dated 16 September, 2010). The pre-beta version is not yet available. See pre-beta version 3.7.04.40 dated 30 April, 2009 below.

In the Detection Range Tables, the detection ranges for a radar of type "CW" were incorrectly being computed. This has now been fixed, however, more care must be taken when specifying a radar free space range (RFSR) for a 1 square meter target with a CW radar, as the detection loss threshold for a CW radar is computed SOLELY on the RFSR for a 1 square meter target, frequency, and radar cross section.

In the HF Communications Project, the reference ionosphere was incorrectly being initialized to use URSI88 coefficients. This has been corrected. The normal default is the CCIR reference ionosphere, in which only the month specified in the "Date/Time" entry is used. If using URSI88 coefficients, the correct date (month, day, year) and time must be provided.


  The current version of AREPS is 3.6.50.33 dated 16 September, 2010. The following are the new features and modifications to the previous version (3.6.50.25 dated 02 August,l 2010). The pre-beta version is not yet available. See pre-beta version 3.7.04.40 dated 30 April, 2009 below.

When using the Tropospheric Ray Trace project and creating an output file with all traced parameters (range, height, angle, etc.) for each ray, some computed parameters were being incorrectly written to the file. This has been corrected.

Automatic extrapolation of the user-specified refractivity profile from the topmost level to the maximum display height, based on the ITU standard reference atmosphere, has been modified such that the profile is extrapolated using the last gradient up to 1 km (if less than the display height), then from 1 km to the maximum display height is extrapolated using the ITU standard reference atmosphere.

APM Version 2.5.04 has been integrated.


The current version of AREPS is 3.6.50.25 dated 02 August, 2010. The following are the new features and modifications to the previous version (3.6.50.20 dated 26 April 2010). The pre-beta version is not yet available. See pre-beta version 3.7.04.40 dated 30 April, 2009 below.

When creating an area coverage display, attempting to create a Google Earth .kml file when Google Earth is not installed on your system caused the AREPS application to crash and exit ungracefully. This has been corrected such that it will give you a warning message.

When attempting to plot an antenna pattern for select HF antenna types in the Antenna Editor Window, an error occurred within the VOACAP .dll, causing AREPS to crash and exit ungracefully. This has been corrected.


The current version of AREPS is 3.6.50.20 dated 26 April, 2010. The following are the new features and modifications to the previous version (3.6.50.16 dated 30 March 2010). The pre-beta version is not yet available. See pre-beta version 3.7.04.40 dated 30 April, 2009 below.

Upon starting the AREPS application, if the operator pressed "Cancel" when the EM system database was being read, the portion of the EM system database not yet loaded was inadvertently deleted. This has been corrected.


The current version of AREPS is 3.6.50.16 dated 30 March, 2010. The following are the new features and modifications to the previous version (3.6.50.13 dated 16 March 2010). The pre-beta version is not yet available. See pre-beta version 3.7.04.40 dated 30 April, 2009 below.

The Target RCS window form did not allow the user to enter more than 100 frequency and RCS values. This has been corrected.


The current version of AREPS is 3.6.50.13 dated 16 March, 2010. The following are the new features and modifications to the previous version (3.6.50.12 dated 22 February, 2010). The pre-beta version is not yet available. See pre-beta version 3.7.04.40 dated 30 April, 2009 below.

The AREPS support contact e-mail and the AREPS web page URL in the Help->Technical Support section has been corrected .


The current version of AREPS is 3.6.50.12 dated 22 February, 2010. The following are the new features and modifications to the previous version (3.6.50.10 dated 16 February, 2010). The pre-beta version is not yet available. See pre-beta version 3.7.04.40 dated 30 April, 2009 below.

When displaying coverage diagrams of electric field strength using the Communications decision aid under the Standard Project, an error occurs when trying to display height vs. electric field strength, or electric field strength vs. range. This has been corrected.

The current version of AREPS is 3.6.50.10 dated 16 February, 2010. The following are the new features and modifications to the previous version (3.6.50.08 dated 16 February, 2010). The pre-beta version is not yet available. See pre-beta version 3.7.04.40 dated 30 April, 2009 below.

The Signal-to-Noise ratio was being computed incorrectly for the Communications decision aid product in the Standard Project. This has been corrected.
The recieved power table grid of numbers created from the right-click functionality in the Received Power display, under the Communications decision aid product, shows incorrect values for the received power. This has been corected.

The current version of AREPS is 3.6.50.08 dated 16 February, 2010. The following are the new features and modifications to the previous version (3.6.05.03 dated 29 December, 2009). The pre-beta version is not yet available. See pre-beta version 3.7.04.40 dated 30 April, 2009 below.

Modified the time display in the MUF/LUF/FOT graphic to display time in hours:minutes in the status window.
Corrected an error in the propagation loss to electric field strength conversion for APM coverage diagrams, which affected both the numerical values and the coverage display.
In the Radar Detection Range Tables display, when using the "Save As" feature to save the numeric values in ascii text format, the values were not saved. This has now been corrected.

The current version of AREPS is 3.6.05.03 dated 29 December, 2009. The following are the new features and modifications to the previous version (3.6.04.69 dated 01 December, 2009). The pre-beta version is not yet available. See pre-beta version 3.7.04.40 dated 30 April, 2009 below.

Added more robust error checking for automode operations, particularly when starting AREPS from the command line. If an error should occurr, an error file will be written either into the automode folder or if it exists, the project folder.

Added vertical and horizontal scroll bars to the folders and drive option window just in case our screen is not large enough to view the entire window when it opens.

The current version of AREPS is 3.6.04.69 dated 01 December, 2009. The following are the new features and modifications to the previous version (3.6.04.58 dated 03 September, 2009). The pre-beta version is not yet available.

Modified the AREPS Lite project to now consider the communication antennas defined within the antenna editor window.

Modified the tropospheric raytrace project window to "toggle" between entries of antenna elevation angle / vertical beamwidth and maximum / minimum angle. In addition, modified the display to show rays for heights below mean sea level in a cross ocean/land boundary situation.

Added an additional data quality check in the numerical weather prediction section of the environment creation program to insure pressures levels equal to zero millibars are excluded.

Added to the environment creation program, the capability to export environment profiles in a XML formatted file appropriate for use by our new Radio Frequency Propagaton Service (RFPS). Contact AREPS technical support for details of RFPS.

Version of AREPS is 3.6.04.58 dated 03 September, 2009. The following are the new features and modifications to the previous version (3.6.04.54 dated 10 August, 2009). The pre-beta version is not yet available.

In order to reflect a true isotropic antenna, removed the ability to change the antenna gain to a value other than zero. If you want to use an antenna gain other than zero for your omni-directional antenna, select the gain table versus elevation/azimuth angle type (Type 111).

Resolved an error in the communications and antenna editor windows which cause the window's value not to populate correctly when the system is opened. This effect was related to the vertical beamwidth and gain values for the cosecant-squared, SinX/X, and Gaussian antenna types.

Version of AREPS is 3.6.04.54 dated 10 August, 2009. The following are the new features and modifications to the previous version (3.6.04.51 dated 22 July, 2009). The pre-beta version is not yet available.

Removed the ionospheric 3D raytrace project. The 3D ionospheric raytrace model is undergoing major modifications not only to resolve some errors but to vastly improve its efficiency and resulting execution time. Until such time as the 3D ionspheric raytrace model has been finalized, it has been removed from AREPS. Should this cause a major problem for your funded use of AREPS, please contact AREPS technical support.

Resolved an error in the research project that caused a file not found error to occur when selecting an atmospheric file from the dropdown menu.


Version of AREPS is 3.6.04.51 dated 22 July, 2009. The following are the new features and modifications to the previous version (3.06.04.50 dated 09 July 2009). The pre-beta version is not yet available.
Modified the two database utility windows, "Add to current database using master database" and "Display current database information", to support the addition of antennas to the database and the separation of emitters into their two components, radars and radios.

Resolved an error that prevented the optional project bitmap and jpg image files from being created during an automode execution. However, regardless of the global settings to save these optional files, they will not be created if AREPS is running in a minimized mode or in its automatic background service (ABS) mode. In order to create these images, a coverage display window needs to be created and made visible. This is not possible in a minimized or ABS mode.

Within the environment program when using a numerical weather prediction (NWP) file, resolved a duplicate pressure error in a vertical profile when one of the level's pressure is reported as -9999, or undefined. For all other duplicate pressure level situations within a vertical profile where the temperatures or humidities are different at the same pressure, the pressure error remains in force. While it is recognized that data truncation processes do occur while creating the NWP files, duplicate vertical pressure levels with differing temperatures or humidities are a physical impossibility. We feel it is responsibility of the NWP file creator to correctly populate the data file.


The current version of AREPS is 3.6.04.50 dated 09 July, 2009. The following are the new features and modifications to the previous version (3.06.03.04 dated 05 November 2008). The pre-beta version is not yet available.
Resolved an issue with using the correct units of wind speed within the Research project. When units of knots were entered, the conversion to meters for internal calculations was incorrect.

Resolve an array out of bounds error within APM.

Troposcatter calculations within APM, for any path containing terrain, have been temporarily disabled until an issue can be resolved. Troposcatter calculations over water performs normally as in previous versions of APM.

Within the 3D ionospheric raytrace, added the capability of changing the color of the rays. The color change is made from the Options -> Configuration -> Colors menu.

Resolved a number of small issues identified since the release of the AREPS version 3.6.03.04 that were identified during the creation of the pre-beta version. These issues did not effect the calculation results.


The pre-beta version of AREPS is 3.7.04.40 dated 30 April, 2009. The following are the new features and modifications to the most current released version (3.06.03.04 dated 05 November 2008) of AREPS.
Added a radio (AM, FM, shortwave) and television broadcast project. In so doing, combined into a single project window, all the inputs necessary for propagation within three frequency regimes, AM radio (< 1700 KHz), shortwave or HF radio (2 to 32 MHz), and FM radio/television (> 32 MHz). For AM radio, the propagation model used is the LF-MF model of NTIA as modified by us. For shortwave radio, the propagation model used is that of VOACAP. For higher frequency transmitters, the propagation model used is our Advanced Propagation Model (APM). Three questions that may be addressed are one, given my transmitter location how much area does my broadcast cover; two, given my intended audience area, where may I place my transmitter in order to maximize the coverage of my listening audience; and three, given the location of my transmitter, what other stations may interfere with my signal. Broadcasting is a hugely complicated process so this project has been specifically designed for automation. Thus, the operator is asked for only a bare minimum of input decisions and the software will make all the other propagation considerations. Please read the on-line help or the user's manual for a complete description of this new project.

Enhanced the antenna editor to allow for specification of commercial broadcasting antenna systems such as one would find associated with their own local AM radio station.

Added a world-wide database of surface dielectrics to support the radio and television broadcast project.

Added an acoustic loudspeaker project. The loudspeaker project is a new direction for the SSC Pacific Atmospheric Propagation Branch. Since the initialization of the branch, the focus has been upon electromagnetic and electro-optic propagation. This project performs an assessment for atmospheric acoustics. The propagation model used is the CASS/GRAB underwater acoustic model with input adaptation techniques described by Johns Hopkins University, Applied Physics Laboratory. Please read the on-line help or the user's manual for a complete description of this new project.

Enhanced APM to support the broadcast automation process.

Modified the main window, menu system, toolbar system, and options to reflect a new configuration feature of AREPS. AREPS may now be configured for only a broadcasting capability or for its complete capability. The configuration is made to simplify AREPS for those users only interested in broadcasting capabilities. This configuration option is found within the Program Flow option reached from the Options menu item.

Updated the on-line help to reflect all new visible features of AREPS. Updated all supporting documentation such as the user's manual, the installation procedures manual, the system administrator's manual, the software version description, etc. to reflect all aspects of this pre-beta version of AREPS.

Resolved a number of small issues identified since the release of the AREPS version 3.6.03.04.


The current version of AREPS is 3.6.04.06 dated 02 February, 2009. The following are the new features and modifications to the previous version (3.06.03.04 dated 05 November 2008).
For the HF communications project, implemented the Voice of America Coverage Analysis Program (VOACAP) propagation and the National Telecommunications and Information Administration, Institude for Telecommunication Services (NTIA/ITS) HF antenna model (HFANT). In so doing, removed the Prophet HF model.

To support the VOACAP modification, modified the Communication system input window to remove the separation between HF systems and UHF and above systems and created a new Communication System antenna window. The process is to first create an antenna using the antenna system window, and then within the communication system window, assign your newly created antenna. The antenna system window will support antenna types other than those HF types provided as samples by the VOACAP program. Of particular note is the user-defined gain table antenna type. By using this antenna type, you can define your antenna for any frequency, not just HF. In addition, the previously "canned" AREPS antenna types of Omni, SinX/X, Cosecant squared and Gaussian have been been modifed such that the antenna system window will calculate the gain pattern. Once created, you may modify the pattern to include side-lobes or other pattern modifications. This gain pattern is now provided to the Advanced Propagation Model (APM) vice having APM calculate the pattern internally.

In the new antenna system window, we now provide the capability of specifying an azimuthal gain pattern. When this antenna is encountered by APM, the vertical gain pattern will be modified appropriately by the azimuthal gain pattern and its relationship to the azimuth of propagation. Thus, the coverage display will now consider antenna directionality.

Updated the upper-air climatological data. Previously, percent occurrence of surface ducts were only accounted for if they were true surface ducts. Now, the percent occurrence of surface ducts is a combination of surface ducts and elevated surface ducts. See the on-line help for a description of the surface and elevated surface duct. With this new definition, a higher percentage of surface ducting occurrence is seen. In addition, this change also changes the M-unit gradients within the surface ducts and other duct features such as optimum coupling height, trapping frequency, and M-unit deficits (duct strength). These changes are reflected in new surface duct profiles.

Modified the environmental creation program to use the new upper-air database and made small display text modifications (such as spelling out the complete station name, etc.)

Updated the APM to now include propagation loss values at all ranges when you specify your own output heights. The previous version did not include propagation loss values at ranges from the origin to the start of the PE region.


Version of AREPS is 3.6.03.04 dated 05 November, 2008. The following are the new features and modifications to the previous version (3.06.03.03 dated 30 October 2008).
Resolved an issue which prevented the use of a custom wind file within a standard project. Additional parameter checking and a warning message were added to insure that a wind speed greater than zero occurs at the emitter's location in order to have APM perform clutter calculations.


Version of AREPS is 3.6.03.03 dated 30 October, 2008. The following are the new features and modifications to the previous version (3.06.02.90 dated 21 July 2008).
Completely redesigned the Composable ForceNet mode. This mode is now called the AREPS background service (ABS) mode. The ABS mode is not dependent upon the Composable ForceNet application so you may use it for your own application. There are many new features of this mode. Some of the major features are:

  • Creation of Google Earth display files. You do not need the Google Earth application installed on your computer to use this feature.
  • Specification of a numerical weather prediction (MWP) data file and the forecast time to use for environmental data creation.
  • Creating project files as the ABS mode operates, with saving of all normal project and optional data files. This feature is convenient should you want to return at a later time to "redisplay" the results within the normal project window.

Renamed the FalconView overlay to Multi-emitter overlay. In so doing, removed the necessity of having the FalconView application installed on your computer.

Added the option to create Google Earth .kml files to the area coverage display, the ionospheric raytrace display, and the multi-emitter display.

Modified the EM system database listing window to separate radars from radios in the emitter listing.

Implemented the compressed pulse length value for radars. This compressed pulse length is used in the calculation of sea-surface clutter. Modified the Advanced Propagation Model to use compressed pulse length.

Implemented the global terrain range resolution options within the custom terrain editor window. This will now allow you to extract DTED data at whatever range resolution you desire.

Resolved some minor problems relating to propagation loss plot range units and display of signal-to-noise ratio for the coverage display.

Updated the on-line help to reflect all new visible features of AREPS.

Version of AREPS is 3.6.02.90 dated 21 July, 2008. The following are the new features and modifications to the previous version (3.06.02.86 dated 20 May 2008).
Modified the program flow such at if an APM bearing contains no terrain or range dependent atmosphere, and a previous such bearing has been encountered, the previous bearing information is used vice having APM perform a new calculation. This greatly improves the AREPS speed for primarily over-water paths.

Made a change in the propagation loss display such that a height of zero will show a propagation loss values for vertically polarized systems.

Resolved a problem in using DTED terrain with the troposheric raytrace.

Resolved a path issue that caused the working database to be written into the same folder with the master database.

Restructured the "Tab" order for controls in all the AREPS windows.

Restructured the "graying out" of unused entry items within the communications editor window. For example, when the function of the radio is selected to be receive only, the transmitter power text field is disabled.

Within the environment program:
Resolved a file naming problem when using the custom evaporation duct batch mode processing.
Added an additional validity check within the custom columns grid to insure that the data are numeric.
Resolved a problem with the "File" menu system when opening a WMO or custom column data file.
Resolved a latitude problem in the world quadrant assignment for WMO code. This problem did not affect the operation of the program or the validity of the created environmental data file.
Resolved a display problem for the annual bargraph of air-sea temperature differences when the bargraph represents an average of day and night conditions.


Version of AREPS is 3.6.02.86 dated 20 May, 2008. The following are the new features and modifications to the previous version (3.06.02.85 dated 01 May 2008).
Resolved a problem in the environmental creation program for previously obtained NWP files. This problem caused a failure of appending an evaporation duct to the bottom of the NWP upper-air profile, when the NWP data are close to the ocean/land boundary.

Changed the way the coverage display bitmap image is drawn. This change removes the apparent black color when the coverage display is resized.

Changed the way the APM terrain variables are filled. This change will now allow for a terrain profile that has all heights equal to zero but will also allow the ground conductivity to change with range.


Version of AREPS is 3.6.02.85 dated 01 May, 2008. The following are the new features and modifications to the previous version (3.06.02.82 dated 17 April 2008).
Resolved a problem associated with the antenna pattern factors for height-finder radars. The factors, while correct as entered by the user, were being passed to the Advanced Propagation Model inproperly modified. This resulted in greatly reduced detection ranges.

Added to the target specification, the height associated with the estimated radar cross-section for ships.

When the target is a ship, modified the height versus range display to:
Show a warning notice that the coverage display is inappropriate for a ship target.
Disabled the probability of detection versus height display.
Disabled the range table display.

When the target is a ship, modified the probability of detection versus range display to:
Set the display height to the target's RCS height.
Give a warning notice if you change the display height to something other than the target's RCS height.

When the target is a ship, modified the four panel display to disable the probability of detection versus height display.

When the target is a ship, modified the area coverage display to:
Set the display height to the target's RCS height.
Give a warning notice if you change the display height to something other than the target's RCS height.

For the database utility function called Performance Threshold Tables, added the target's RCS height to the XML file listing.


Version of AREPS is 3.6.02.83 dated 24 April, 2008. The following are the new features and modifications to the previous version (3.06.02.82 dated 17 April 2008).
Added a capability to compute an estimated radar cross-section for ships based upon the equation in Skolnik, M. 'Radar Handbook', Edition 3, 2008. This equation is a function of frequency and ship displacement. Refer to the on-line help for further information.

For the database utility function called Performance Threshold Tables, replaced all spaces within the saved file name with underscore characters.


Version of AREPS is 3.6.02.82 dated 17 April, 2008. The following are the new features and modifications to the previous version (3.06.02.81 dated 10 March 2008).
Resolved a "type mismatch" error in the environmental creation program when trying to create an evaporation duct profile using the Monin-Obukhov length stability method.

Resolved a problem with AREPS not ending even though the /e option was used when AREPS is started from the command line.

Modified the command line start options such that if AREPS is started in the minimize (/m) mode, certain initial database and folder questions are not displayed. Because these questions are not displayed, the AREPS default answers are automatically accepted. Contact technical support for further information about these questions.


Version of AREPS is 3.6.02.81 dated 10 March, 2008. The following are the new features and modifications to the previous version (3.06.02.79 dated 26 February 2008).
Resolved a problem with the communications systems window which caused the current value within the bandwidth text field not to be used for performance threshold calculations. A constant default value of 10 Hz was being used.

Revised the tabular (row, column) input control within all windows that contain one, to be consistant in operation when adding a new row by using the insert row toolbar button.


Version of AREPS is 3.6.02.79 dated 26 February, 2008. The following are the new features and modifications to the previous version (3.06.02.78 dated 21 February 2008).
Resolved a problem with the communications systems window which caused the bandwidth text field to become inactive if a frequency greater than 30 MHz was entered.

Resolved a problem with the communications systems window which caused the UHF or HF frame and all the contained controls to become inappropriately inactive if then frequency was entered with units of GHz.

Resolved a problem in the HF communications project window that caused the label of transmitter frequency not to automatically update should the frequency be changed independently within the communications system window.


Version of AREPS is 3.6.02.78 dated 21 February, 2008. The following are the new features and modifications to the previous version (3.06.02.77 dated 14 February 2008).
Resolved a problem with the automode menu that caused a project to be re-executed upon redisplay.


Version of AREPS is 3.6.02.77 dated 14 February, 2008. The following are the new features and modifications to the previous version (3.06.02.76 dated 30 January 2008).
Modified the environment creation program to account for a change in the date and time format used with the numerical weather model input data.

Resolved a problem in the listing of system data when accessed via the Systems Menu, Database Utilities menu item, and then the Display Current Database Information menu item. Now, only the first 100 system parameters are shown in the listing. To view the entire contents of the system, right click on the system name from the listing.

For the environment creation program, resolved an error which prevented access to the first tab of an input method. For example, when using the custom column input method, this error prevented access to the input tab.

For the research project, added to the wind label right-click menu, the option to view the sea state and wind speed conversion table.


Version of AREPS is 3.6.02.76 dated 30 January, 2008. The following are the new features and modifications to the previous version (3.06.02.74 dated 22 January 2008).
Modified the environment creation program to perform additional error checking when executing the program from the command line using standard input and standard output techniques. Should a standard input/output error occurr, the error is now returned in XML format to the calling program.

Modified the automode routines (those used when running AREPS from the command line) and the coverage display routines to output the same data, in the same format, within the optional ASCII text file. This applies to both individual bearing files and a single file that contain multiple bearings.

Resolved an error in converting emitter power from user units to KiloWatts when passing power into APM.

To the optional APM parameters, added the capability of specifying exact heights (relative to local ground/water) for which you would like APM output. The propagation loss and factor data for these heights are included in the optional ASCII text output file.

Added a warning notice and icon to the center panel of the status bar when the optional number of APM output points is less than 300. When the number of APM output points fall below the screen resolution, the coverage display graphic becomes distorted. When the number of output points is just one or two, the coverage display becomes (graphically) completely invalid.

Corrected several spelling errors in the optional output files.


Version of AREPS is 3.6.02.74 dated 22 January, 2008. The following are the new features and modifications to the previous version (3.06.02.73 dated 11 January 2008).
To the Performance Threshold Tables, added an option to include those EM system parameters that are APM input requirements. This feature will allow you to obtain EM systems parameters from the EM database for use in passing to APM without having to write your own extraction routines.


Version of AREPS is 3.6.02.73 dated 11 January, 2008. The following are the new features and modifications to the previous version (3.06.02.72 dated 15 November 2008).
Added a new database utility function called Performance Threshold Tables. This function is reached from the System -> Database Utilities -> Performance Threshold Tables menu item. The purpose of this function is to create an XML formatted file containing system performance threshold values for various combinations of radars/targets, radio transmitters/receivers, and ESM receivers. This performance threshold table may then be used by an external application to do thresholding functions.

Added four new command line arguments that may be used to execute the environmental creation program. These arguments are:
/xf InFileName - create an XML formatted environmental profile file using specifications within the InFileName file
/xr InFileName - create an XML formatted report on the contents of a numerical weather predition (NWP) data file using the specifications within the InFileName file
/xfs - same as /xf but the specification is provided to the program via standard input vice a file and the output is to standard output vice a file
/xrs - same as /xr but the specification is provided to the program via standard input vice a file and the output is to standard output vice a file

For the custom column input method of the environmental creation program, added an option to save the definitions of the columns into the AREPS initialization file. Once saved, whenever the environmental creation program is executed, the columns are automatically defined so you do not have to repeat the process manually. This option is very convenient should you consistantly use the same source for your column data.

Version of AREPS is 3.6.02.72 dated 15 November, 2007. The following are the new features and modifications to the previous version (3.06.02.71 dated 31 October 2007).
Resolved a program flow error when the mouse cursor is moved over the surface-search range table display graphic.

Version of AREPS is 3.6.02.71 dated 31 October, 2007. The following are the new features and modifications to the previous version (3.06.02.70 dated 11 October 2007).
Modified the environment creation program to allow for missing header data in previously obtained numerical weather prediction files. A "how to" document has been placed on our webpage that addresses this particular issue.

Version of AREPS is 3.6.02.70 dated 11 October, 2007. The following are the new features and modifications to the previous version (3.06.02.64 dated 24 August 2007).
For HF combined ground and sky wave communications, removed signal-to-noise and received power from display. This is due to lack of knowledge of receive antenna signal arrival angles from the sky wave component of the propagation path.

For the communications window, moved the bandwidth input from the HF section to the common information section. By now including the bandwidth value and the receive antenna gain, we have now improved our communications threshold routines to allow for the display of signal-to-noise and received power. For version transition reasons, we are not able to update the communications threshold description in the online help. However, we will make this description available on our web page (http://areps.spawar.navy.mil).

Resolve an array index problem in the save optional APM data file. Without this fix, the surface clutter value at the first range step was not listed and the clutter value at the last range step was always listed as zero.

Resolve an error in the Lite project which incorrectly populated the radar dropdown menu with communications systems. Also resolved an units conversion error which caused the Naval Postgraduate School's environmental boundary layer model to compute an inproper evaporation duct profile.

Modified the standard project window to properly set default units to either English or metric as specified by your options settings.


Version of AREPS is 3.6.02.64 dated 24 August, 2007. The following are the new features and modifications to the previous version (3.06.02.63 dated 31 July 2007).
For the automode project, resolved a memory leak issue.

Version of AREPS is 3.6.02.63 dated 31 July, 2007. The following are the new features and modifications to the previous version (3.06.02.62 dated 19 July 2007).
For the range and height displays, added to the right-click options menu, the ability to show, save, and print the actual data shown on the display.

Version of AREPS is 3.6.02.62 dated 19 July, 2007. The following are the new features and modifications to the previous version (3.06.02.54 dated 25 June 2007).
Changed performance thresholding calculations for HF radio systems to include transmitter antenna maximum gain in the conversion from antenna pattern gain to antenna pattern factor. Also, fixed an error in the conversion equation for both communications and radar systems.

Moved all windows' initial screen postion to the left side of the screen to insure the windows are visible for those users with a small display screen.

Added power and gain considerations to calculation of HF electric field.

Modified program flow to avoid an error should the operator close a window while a popup menu is currently displayed.

Made cosmetic changes in the unit abbreviation labels and tabular form column header colors.

Changed the default DTED map display to full map.

For the HF communications project, set the antenna height units to those of the currently saved project vice the universal option for height units.
Version of AREPS is 3.6.02.54 dated 25 June, 2007. The following are the new features and modifications to the previous version (3.06.02.42 dated 10 May 2007).
Changed the URL for AREPS to accommodate our new public server. The new URL is http://areps.spawar.navy.mil. The old server will perform an automatic redirect should you use the old URL of http://sunspot.spawar.navy.mil.

Modified the windows resizing functionality to enhance the automatic adjustments for monitor resolution, font sizes, and system display settings.

Changed the canned default value of maximum number of APM height points. The old default was 384 and the new default is 1000. While this will increase the run-time to a small extent, it will also greatly reduce interpolation issues. You still have the option to reset the default to any value you would like.

Resolved a display issue when viewing received power versus range from an HF ground-wave calculation.

Resolved a display issue for the ionogram option within the ionospheric raytrace project.

Changed some label colors to white vice using the Active title bar color assigned from your computer's system. This resolved a readability issue depending upon the color you have set for your active title bar.

Resolved a number of miss-matched issues related to the maximum and minimum axes display values within the project's options.


Version of AREPS is 3.6.02.42 dated 10 May, 2007. The following are the new features and modifications to the previous version (3.06.02.41 dated 15 February 2007).
For the Ionospheric raytrace and the HF communications projects, resolved a problem in the conversion of local time to Universal Coordinated Time when the local time has a daylight savings time component.

Added an option to automatically modify certain data savings folders when you change your project folder. This option will help overcome confusion in your knowing where certain data files are being saved.

Resolved a problem in releasing computer memory when the height versus range coverage display is closed.

For the research project, disabled the vertical beamwidth text field when a user-defined antenna pattern is selected. Set the lower limit for normalized antenna pattern to greater than or equal to zero vice a lower limit of just greater than zero.

For the HF communications project, included changing the time within the list of activities that will automatically trigger a propagation calculation. In addition, resolved a problem in the automatic calculation when certain transmitters are selected from the dropdown menu.

For the Ionospheric raytrace project, resolved a run-time error problem when the number of vertical elevations is greater than 21.

In the routine that interpolates propagation loss values, resolved a problem when the first interpolation range is zero.

Version of AREPS is 3.6.02.41 dated 15 February, 2007. The following are the new features and modifications to the previous version (3.06.02.40 dated 18 January 2007).
For the HF ionospheric raytrace program, updated the International Reference Ionosphere (IRI) coefficients and the raytrace's dynamic link library, extending the period of forecast to 31 December 2010. If you do not have the PIM climatology files, you may want to consider obtaining them. They may be downloaded from your AREPS program software page. To assist you, we also provide a Microsoft PowerPoint presentation with complete download and installation procedures.

Resolved a problem in the area display when drawing upon the FalconView map. This problem occurred when you closed FalconView externally to AREPS while AREPS was trying to draw upon the map. You will now receive a notice saying the FalconView map is no longer available for your current display process.

For the surface climatology of the environment program, modified the program flow to always display the currently selected graph type (bargraph or cumulative frequency distribution), when you change the data type being displayed.

Updated the software version description document (svdAREPS_36.pdf) to reflect the new version numbers for the ionosphere raytrace dynamic link library and the IRI coefficient file.


Version of AREPS is 3.6.02.40 dated 18 January, 2007. The following are the new features and modifications to the previous version (3.06.02.35 dated 08 December 2006).
Changed the functionality of the right-click upon the labels associated with the dropdown menus for the atmosphere, the terrain, and the wind. Previously, a right-click on any of these labels would allow you change data folders. Now, a right-click will give you the option to open a file browsing window so you may choose a file external to the defined AREPS folder structure. This additional flexibility also relieves the requirement that your files must have a particular file extension in order to be selected. This new functionality applies to all projects that have these dropdown menus.

Resolved a problem in changing units of antenna height, vertical beamwidth, and elevation angle when you change the APM mode. This problem applied only to the Research project.

Added showing of the project's label upon the loss vs range/height displays. Showing the project's label reduces the confusion between displays when multiple displays are open.

Version of AREPS is 3.6.02.35 dated 08 January, 2007. The following are the new features and modifications to the previous version (3.06.02.32 dated 18 December 2006).
Modifed the program flow to increase the probability of detection calculation speed when the target's radar cross-section is finely specified in frequency and angle.

Resolved a problem in calculating and displaying surface probability of detection, propagation loss, or propagation factor when the project's terrain height is below sea-level.

Within the Show, Save, and Print data window, added the values of latitude and longitude that correspond to the range and bearing of the data being displayed.

Within the Show, Save, and Print data window, resolved an error in the vertical scroll bar which prevented the data at the surface level from being displayed.

Version of AREPS is 3.6.02.32 dated 18 December, 2006. The following are the new features and modifications to the previous version (3.06.02.31 dated 07 December 2006).
Updated APM to version 2.3.04.
  • Added an error check in APM such that for steep terrain near the emitter, the calculated propagation angle is not outside the angle validity of the PE algorithm. Should this condition exits, APM will return an error number of -46.

  • The calculation of permittivity and conductivity has been extended down to 1 MHz. Previous versions of APM automatically calculated the permittivity and conductivity as a function of frequency from curve fits to Figure 1 in ITU-R P.527-3. The equations were only applicable between 100 MHz and 100 GHz. The DIEINIT routine has been modified and is now valid for frequencies between 1 MHz and 100 GHz.

Updated the on-line help and user's manual to reflect all new visible features of AREPS. In addition, updated the other supporting documentation (installation procedures, system administrator's manual, software version description, software test document, and statement of functionality) to reflect AREPS version 3.6.

Version of AREPS is 3.6.02.31 dated 07 December, 2006. The following are the new features and modifications to the previous version (3.06.02.25 dated 26 October 2006).
Resolved a problem in using gridded numerical weather data (COAMPS data) in the FalconView project, when the AREPS created environment contains mixed environmental profiles (some profiles with an evaporation duct, some without and bearings with both).

Added a checkbox to optionally include surface clutter in the APM calculations for the FalconView project. The required wind speed and direction are automatically read from the environmental file selected or from the gridded numerical weather data. If wind data are not available, the clutter option will be disabled. Please understand, including surface clutter calculations will increase the project's execution time.

To the optional APM data ASCII output file, added the propagation loss and propagation factor data relative to a fixed height above the ground. AREPS sets this height to one meter above the ground. There is currently no user option to specify your own height(s).

The U.S. Air Force is deploying a Standard Desktop Configure (SDC), such that a desktop user does not have write permissions outside of his own space under the Documents and Settings folder. Because AREPS expects to have write permission for its Data folder (a sub-folder under the AREPS application folder), the SDC caused AREPS to fail. To resolve this issue, upon the first use of AREPS after its installation, AREPS now checks for the SDC. If it exists, AREPS creates the folder C:\Documents and Settings\UserName\Application Data\AREPS\Data and writes the initialization file here. If AREPS is already installed when the SDC is applied, additional off-line procedures need to be taken. Please contact AREPS technical support.

Version of AREPS is 3.6.02.25 dated 26 October, 2006. The following are the new features and modifications to the previous version (3.06.02.23 dated 11 September 2006).
Resolved a problem in the angle increment calculation for the tropospheric ray trace. Please understand this ray trace is a small angle approximation to Snell's law, used to examine low angle refractive effects. Refraction ceases to be an issue for angles above about 10 degrees. For angles above about 20 degrees, the approximation technique using in the raytrace begins to fail.

Added to the right-click options menu of the troposphere raytrace, the ability to show results on geometric curved and dual-curved earth axes in addition to the normal 4/3 earth axes.

Resolved an error in drawing the -10 degree reference angle line within all the height versus range displays.

Resolved a units conversion error between air temperature and saturation vapor pressure within the unit converter tool.


Version of AREPS is 3.6.02.23 dated 11 September, 2006. The following are the new features and modifications to the previous version (3.06.02.22 dated 10 August 2006).
Resolved a problem related to the smooth transition between the Ray Optics sub-model and the Parabolic Equation sub-model of APM for very close in ranges.

Made a corrrection in the calculation of the propagation factor within the Ray Optics sub-model of APM.

Corrected an input unit (knots and meters-per-second) problem for wind speed when the user modifies his environmental file in a text editor external to the AREPS GUI.

Version of AREPS is 3.6.02.22 dated 10 August, 2006. The following are the new features and modifications to the previous version (3.06.02.21 dated 07 August 2006).
Resolved a problem in the display of DTED map data when the dynamic range of heights is less than 50 meters over the entire project area.

Version of AREPS is 3.6.02.21 dated 07 August, 2006. The following are the new features and modifications to the previous version (3.06.02.20 dated 14 July 2006).
To the optional APM ASCII output file, added two values, the maximum PE angle and the PE range step. These are internally calculated numbers, either derived from values of EM system frequncey, project maximum range, etc. or from values of maximum PE angle and range step multiplier entered directy within the project's APM settings. By examining these calculated numbers, a user may adjust the maximum PE angle and range step mulitplier numbers to obtain a range step appropirate to the particular project. This feature is mainly for those users of AREPS who wish to use the PE only mode of APM operation.

Resolved a clutter-to-noise calculation problem within APM for near-range (high grazing angle) airborne transmitters.

For the environment program, replaced all Celsius to Kelvin temperature conversions with a universally defined conversion constant vice using a code embedded number.

Modified the way a user is able to enable the debug mode of AREPS operation. Instructions for doing this will be given by the AREPS technical support personnel on a case-by-case basis should the debug mode be required for problem resolution.

Version of AREPS is 3.6.02.20 dated 14 July, 2006. The following are the new features and modifications to the previous version (3.06.02.10 dated 10 July 2006).
Resolved an error that caused AREPS to exit when a window containing a tabular form is opened.

Version of AREPS is 3.6.02.10 dated 10 July, 2006. The following are the new features and modifications to the previous version (3.06.02.07 dated 19 June 2006).
Added a new menu item called Tools. Moved the unit converter utility program from the Window menu to the new Tools menu.

For all windows within AREPS and the environment program that have a tabular (spreadsheet) input form, standardized the menu wording and toolbar button functions for inserting a row, removing a row, and cleaing the entire form.

Added a registery entry for the environment program's main window postion. Thus, if the environment program has never been opened, it will not overlay exactly upon the AREPS window and if it has been opened, it will re-open in the same postion where it was last closed.

Resolved an error that cause AREPS to fail when an existing target window is opened.

Version of AREPS is 3.6.02.07 dated 19 June, 2006. The following are the new features and modifications to the previous version (3.06.02.03 dated 07 June 2006).
Added the ability of AREPS to recognize the installation of FalconLite vice the entire FalconView program. This version of AREPS does not support FalconLite. If this is a requirement for you, please contact AREPS technical support.

Resolved an error in the coverage display when the number of display colors exceeds 14.

Version of AREPS is 3.6.02.03 dated 07 June, 2006. The following are the new features and modifications to the previous version (3.06.01.45 dated 08 May 2006).
Implemented a new version (2.3.00) of the APM. This version of APM is not backwards compatable with older versions of AREPS. However, the incompatabilty will not cause an error with any previous version of AREPS as the installation program does not remove previous versions of APM.
  1. Made a correction to the algorithm for computing grazing angles. This correction resolves an APM -100 error.
  2. Modified the quarter-wave dipole antenna pattern.
  3. Added a number of environmental input data checks for those who use APM externally to AREPS.
  4. Made several modifications that have no effect upon AREPS.

Within the radar editor window, activated the "Save" toolbar icon and "File" & "Save" menu system when any units are modified.

From the Systems menu, Display Current Database Information item, modified the column formats and labels to properly show missile flight profile data.

From the custom terrain editor window, resolved an error when the mouse moved over the DTED map picture when no DTED exists.

Resolved an error that caused AREPS to terminate after the execution of a "Lite" project.

Resolved an error in reading the maximum PE angle from the project's initialization file.

An option for gasseous absorption is to have AREPS calculate it from inputs of surface air temperature and humidity, either entered directly or read from an environmental file. This calculated value is now included within the optional APM ASCII text output file.

Disabled the right mouse click popup menu for antenna polarization labels.

Corrected several minor spelling errors, one of which caused the selection of the radar function missile acquisition when it should have been missile guidance.

Made minor wording changes to the mouse move labels for the HF ground wave coverage display, depending upon which parameter (signal-to-noise, electric field, etc.) is shown.

Implemented an uniform file naming convention for all AREPS output files.

Updated the on-line help and user's manual to reflect all new visible features of AREPS. In addition, updated the other supporting documentation (installation procedures, system administrator's manual, software version description, software test document, and statement of functionality) to reflect AREPS version 3.6.


Version of AREPS is 3.6.01.45 dated 08 May, 2006. The following are the new features and modifications to the previous version (3.06.01.44 dated 19 April 2006).
Added the surface wind speeds to the optional APM ASCII text output file.

Resolved an error in the area coverage display when you select DTED terrain but there is no terrain within your coverage radius.

Resolved an error in reading a wind file should the wind file contain a folder and file name (an old format).

Changed some internal error checking and debugging features that are invisible to the user.


Version of AREPS is 3.6.01.44 dated 19 April, 2006. The following are the new features and modifications to the previous version (3.06.01.43 dated 27 March 2006).
Resolved an error in the radar range table display which caused detection ranges not to be recalculated when a different target is selected from the columns' dropdown menus.


Version of AREPS is 3.6.01.43 dated 27 March, 2006. The following are the new features and modifications to the previous version (3.06.01.41 dated 22 March 2006).
Resolved an error when drawing the terrain upon a curved earth surface within the troposphere raytrace project.

Resolved an error in the custom terrain window that prevented the Save toolbar button to become active when you make a modification to your terrain profile. Also, changed the default range and height units to those of your selected unit system (metric or English).

Resolved an error that caused the text of the Execute item on the Run menu to reflect an out-of-date project name.


Version of AREPS is 3.6.01.41 dated 22 March, 2006. The following are the new features and modifications to the previous version (3.06.01.39 dated 27 February 2006).
For the HF communications and ionospheric raytrace projects, added the capability of having AREPS automatically obtain current values of sunspot number, solar radio flux, and planetary K-index values from our internet/SIPRNET homepages.

For the HF communications project, added the ability to change the power and the required signal-to-noise values "on the fly." This allows you to do "what if" assessments without having to edit the system parameters of the transmitter or receiver.

For the APM options, when you select the "Compute using..." option for gaseous absorption, added a feature to do the computation immediately and display the results in the center panel of the status bar. Since attenuation is a function of frequency, this feature only applies to an active project with a defined transmitter.

Modified the Help menus of AREPS and the environment file creation program, unifying them in wording and functionality.

Updated the on-line help to reflect the new visible features of this AREPS version.

For the Environment File creation program...
To the profile description, added the Marsden square number for all input methods that contain latitude and longitude information.

To the profile description, added surface wind speed and direction for all input methods that may contain such data. The methods that may include winds are WMO import, Metcast/JMV, surface climatology, custom column, and numerical weather prediction (NWP) data.

Modified the profile extraction routine for NWP data to accomodate data on an irregularly defined latitude and longitude grid.

For NWP data, added to the profile description, the distance between the interpolated profile and the closest NWP grid point.

In NWP formatted data that includes sea-surface temperature for automatic evaporation duct calculations, should the sea-surface temperature be reported as missing (-9999), we now set the sea-surface temperature to that of the surface air temperature. This will cause a neutral profile Paulus/Jeske evaporation duct profile to be calculated and appended to the upper-air profile.

For the surface climatology input method, added an annual average bargraph display for DCS data where all monthly averages can be view in a single picture.


Version of AREPS is 3.6.01.39 dated 27 February, 2006. The following are the new features and modifications to the previous version (3.06.01.38 dated 10 February 2006).
Add to the startup process, a check for the accessability of certain vital folders (EM system, terrain, and numerical weather prediction) as defined in your AREPS initialization file (areps.ini). If any of these folders are not accessable, you will now receive a warning notice. This is to accomodate passwords, network failures, server failures, etc.

Resolved an error in numerical weather prediction folder location.

Modified the AREPS File menu - Close for Target and ESM systems to recognize the previous "Save" of the system. This modification removes the "Do you want to save the system" question when the Target or ESM system window is being closed.

Updated the on-line help and the user's manual to reflect the new visible features of this AREPS version.

For the Environment File creation program...
  1. Upgraded the Naval Postgraduate School boundary layer model to their version 2.0.
  2. Resolved an error in the decoding of the globe quadrant for WMO code.
  3. Resolved an error in the decoding of the station elevation for a mobile WMO radiosonde report.
  4. Added additional error checking while reading and processing a HPAC formatted NWP environment file.
  5. Added a view, save, and print option to the right-click menu of the surface climatology histograms.
  6. Added a new line to the environment file to identify which evaporation duct model was used to create the evaporation duct portion of the environment profile.
  7. Created consistancy in the File (new and open) menu system to activate or deactivate for upperair climatology, surface climatology, and NWP.
  8. Added the universal unit converter to the Window menu.
  9. For custom columns, added horizontal and vertical scroll bars to the input text box and grid

For the batch processing of evaporation duct profiles...
  1. Added the capability of using either the Paulus/Jeske model or the Naval Postgraduate School model.
  2. Added a new "barebones" evaporation duct profile file format. This new format applies to files with the optional .met file extension. This simplified format may be used for importing data into other applications such as MATLAB.
  3. Deactivated the option for optical M-unit calculations. This feature may be reimplemented should an EO assessment tool desire to use AREPS to create vertical profiles of height and optical M-units.
  4. Resolved an error which caused multi-profile contamination between profiles
  5. Added absolute humidity calculations
  6. For profile failures due to out of bounds input values, turned the grid row color to red to help identify the offending surface observation.


Version of AREPS is 3.6.01.38 dated 10 February, 2006. The following are the new features and modifications to the previous version (3.06.01.31 dated 26 January 2006).
Make numerous modifications to the custom terrain editor window to include the capability of importing unformatted terrain data into the custom terrain editor window.

Resolved an error in the 4-panel display that prevented the refresh of the coverage display when the target, ESM receiver, or communications receiver were changed.

Made numerous label and option changes in preparation for AREPS' use of Shuttle Radar Topography Mission (SRTM) terrain data. These changes however, will not be visible until the SRTM capability is fully implemented.

Resolved an error in the path of the EM system database file when AREPS is initialy started without the database file.

Modified the "Save as graphic image" routine of the troposphere raytrace project to add the terrain map to the final image.

Resolved an error within the raytracing portion of APM for certain terrain data. This error was reported to the operator as an APM -100 error.

Updated the on-line help to reflect the new visible features of this AREPS version.


Version of AREPS is 3.6.01.31 dated 26 January, 2006. The following are the new features and modifications to the previous version (3.06.01.30 dated 17 January 2006).
Added labels to the window used to display APM data. These labels show height, range, propagation loss, and other items as the mouse moves about the window.

Removed a line-of-sight check box from the tropospheric raytrace project. This feature is in development and should not have been exposed at this time.

Resolved an error in the propagation loss versus range display which drawed the curve to values less than -32000. These negative values are internal use flags to AREPS and represent features such as "not calculated," "below terrain height," etc. and should never to exposed to the operator.


Version of AREPS is 3.6.01.30 dated 17 January, 2006. The following are the new features and modifications to the previous version (3.06.01.27 dated 04 January 2006).
Resolved an error in AREPS passing a variable to APM for the full coverage mode.

Added the capability to save optional graphic images while AREPS is functioning it its automode. These images will be save only if AREPS is not minimized.

Hid two option buttons on the APM options window when the window is opened from a specific project. This was done to avoid confusion between the default project options and specific project options.

Modified some internal debugging functionality to improve program execution speed.

Updated the on-line help and user's manual to reflect all the new features of this AREPS version.


Version of AREPS is 3.6.01.27 dated 04 January, 2006. The following are the new features and modifications to the previous version (3.06.01.20 dated 05 October 2005).
Modified APM to do full coverage. This full coverage mode provides propagation information in regions where the PE and XO models do not. Be sure to read the on-line help about the full coverage mode and its assumptions.

Added the capability to optionally append an evaporation duct profile to the bottom of NWP upper-air profile. This requires a special version of the COAMPS HPAC file. Contact technical support for information about expanding this capability to your own NWP data files.

Added additional error checking to NWP profile creation - non decreasing pressures

You may now place the ionosphere data on a network drive or in another folder of your choosing. This is done from the Folders and Drives menu item of the Options menu. If your current ionosphere data folder is the default as installed by AREPS, AREPS will move all the data files to their new location for you. If your current ionosphere data folder is not the AREPWS default, you must move all the data files yourself. Please read the on-line help so you will know exactly what is being asked of you.

Created a whole new terrain file generator, allowing you to optionally create your own terrain profiles from DTED data.

Added the capability of remove text (possibly classified) from all the graphic displays. By doing this, you may print or save the decision aid graphic and provide it to someone for use in an unclassified environment.

Re-worked the labels on the loss vs range/height display and other decision aids to bring greater uniformity in text, text placement, and menu structure.

Added checking in order to eliminate the calculations of APM on bearings for which previously created bearings contained the same input parameters. This checking increases the speed for project calculations in over-water or no terrain projects.

Changed the upper-air environmental profile extrapolation method to one recommended by the International Telecommunications Union. In so doing, we have removed the other optional extrapolation techniques. This ITU technique provides a more realistic refractive profile at extreme heights. This is done in preparation for extending AREPS calculations to satellite altitudes.

Include clutter numbers in optional ascii file.

Modified the function of the debug mode to provide better technical support services.

Resolved an error in the CFN output for ESM cases.

Added a full cursor to coverage display to better enable you to obtain exact locations.

Updated the on-line help and user's manual to reflect all the new features of this AREPS version.

Version of AREPS is 3.6.01.20 dated 05 October, 2005. The following are the new features and modifications to the previous version (3.06.01.19 dated 28 September 2005).
Added the capability of saving and reopening an ionospheric raytrace project.

For the ionospheric raytrace and homing displays, improved the speed of the graphic redisplay when the window is resized or the earth surface depiction is changed.

Version of AREPS is 3.6.01.19 dated 28 September, 2005. The following are the new features and modifications to the previous version (3.06.01.16 dated 14 September 2005).
For the area display, added the capability of viewing and changing the DTED terrain height increment. You may not at this time however, change the color assignments for each height increment.

Modified the toolbar menu system to bring more uniformity of functionality to these buttons as they apply to every open window. Added a toolbar tip text to show you what each button will do when clicked on.

Added additional internal error checking to prevent multiple and simultaneous executions of the Advanced Propagation Model (APM).

Added "Help Steps" to the tropospheric raytrace project.

For an unregistered AREPS, resolved an error in the placement of the "data source" text box in the target window.

Updated the on-line help to reflect all the new features of this AREPS version.

Version of AREPS is 3.6.01.16 dated 14 September, 2005. The following are the new features and modifications to the previous version (3.06.01.08 dated 26 August 2005).
For the tropospheric raytrace, when only one ray is requested, we now set the initial angle to either the minimum angle (if minimum and maximum angle are entered) or the elevation angle (if a system is entered). Previously we set it to one half the sum of the minimum and maximum angle or one half the sum of the elevation angle and the beamwidth.

Added a new display type, called "detection only." This display type corresponds to ESM, communications, and CW radar systems. This new display type resolves a problem when viewing these systems within the 4 panel graphic decision aid.

Added new error checking associated with using the FalconView program. Should AREPS fail to start the FalconView program, this error checking will identify the exact process that failed. This error checking also allows AREPS to exit gracefully if your version of FalconView is incompatable with AREPS. FalconLite is such a version.

Added a command line /h or /help option to obtain help on executing AREPS with a command line argument.

Modified the InstallShield installation program to force the installation of certain component files. A bug in the InstallShield software caused the "unckecking" of these items from the installable components tree. Since these components were at the bottom of the tree, a user installing AREPS would not necessarily see these components were not checked for installation. This is especially true for those users who selected "Typical" vice "Custom" as their install option, as the installable components tree is not shown to the user for the typical install method. Not having these components would cause the HF communications and ionospheric raytrace projects to fail.

Added a description of the automode menu file within the details view of the open and remove window.

Resolved an error in writing terrain scatter effectiveness values in the optional ASCII APM and terrain files.

Resolved an error in closing AREPS after executing an automode run menu from the AREPS command line.

Resolved an error in extracting clutter-to-noise values from the APM output results.

To avoid what appears to have caused confusion in our version numbering scheme, we have dropped the leading zero in the second segment of the version number. Thus, this is version 3.6 and not 3.06.

Version of AREPS is 3.06.01.08 dated 26 August, 2005. The following are the new features and modifications to the previous version (3.04.1.37 dated 19 May 2005).
Implemented a new version of APM which not only resolves some reported deficiencies, but now includes double precision mathemathics. This version of APM is not backwards compatable with previous versions so any applications that use the APM.dll will have to be modified.

Implemented a new 4 panel graphic decision aid. The quick start 4 panel project window opens by clicking the quick-start button from the AREPS main window. Each panel of the window is interactive with the other panels in that mouse moves, cross hair moves, right-click menu option changes, etc. are automatically reflected in the other panels. For example, by left-clicking and dragging the mouse over the coverage display, the height and range displays will automatically change to reflect the new range and height. To activate this new display, we added a new quick-action command button to the main AREPS window.

Added a new option to the program flow options to set your default initial decision aid to either the standard height versus range coverage display or the new 4 panel decision aid display.

For the coverage coverage display and the detection range versus range/height display, added the capability of changing the communications or ESM receiver on-the-fly without having to re-execute the propagation model.

For the range and height displays, added coloring to reflect the location of the ground. Thus, it makes it easier to see where terrain masking occurs.

For all decision aids, modified the display to include the security classification of the project.

For the Ionogram display of the Ionospheric raytrace project, added the capability of viewing certain ray data as the mouse moves over the display. Also added to the right mouse click menu, the capability of showing the homing raytrace for the frequency associated with the mouse's position on the ionogram.

Added a new legend color to the area display. This legend shows altitudes where radar detection or ESM/communications ranges are not calculated. These non-calculation regions are where the propagation angle exceeds the maximum PE angle. This legend is for clearity so an operator will not automatically think there is no coverage at high angles. These high angles correspond to the white area of the vertical coverage display.

Modified the terrain and wind editor windows to remember the last folder used to save these data. This eliminates the need to continually browse for the folder you want to use.

Within the AREPS environment program, added an error message if no significant atmospheric levels were found within a pasted WMO message.

Within the AREPS environment program, resolved an error which prevented the batch processing of surface observation data to create multiple evaporation duct profile files.

Resolved an error in the way global and project options are saved to the AREPS initialization file.

Within the uninstall package, added the capability of removing AREPS keys from your computer's registry. We also changed the uninstall messages to notify you that AREPS will not automatically remove folders and files that you created since the AREPS installation. This prevents the automatic deletion of EM databases, etc. that you may wish to archive before you remove them yourself.

Changed the procedure for automatically saving the Composable ForceNet .XML EM database file. By doing this, we not only improved the performance of AREPS but insured that the EM database used within Composable ForceNet is consistant with the EM database used by the AREPS operator in the AREPS stand-alone mode.

Updated the four sample projects included with the AREPS installation to reflect all new features of this AREPS version.

Updated the on-line help and the user's manual to reflect all the new features of this AREPS version.

Version of AREPS is 3.04.1.37 dated 19 May 2005. The following are the new features and modifications to the previous version (3.04.1.36 dated 18 April 2005).
Resolved an error in the area display which prevented the drawing of the performance lines.

Resolved an error in the area display which prevented the mouse click height and height units of the parent coverage display being passed to the area display.

Version of AREPS is 3.04.1.36 dated 18 May 2005. The following are the new features and modifications to the previous version (3.04.1.32 dated 25 April 2005).
Within AREPS and the AREPS environment program, added a new options menu item allowing you to change default colors. This colors feature is reached from the Configuration item on the Options menu.

Modified the maximum range table display to include not just the maximum detection, communications, or ESM vulnerability range, but to also show ranges of performance and no performance based upon ducting, optical interference, and clutter effects.

For the coverage coverage display and the detection range versus range/height display, added the capability of changing the target on-the-fly without having to re-execute the propagation model.

In all windows referencing the Composable ForceNet input and output folder, added error checking to insure these folders are 1) present and 2) writable. This error checking gracefully handles situations where the Composable ForceNet server not available on the network or where write protection and other secuity setting may prevent folder use.

Within AREPS and the AREPS environment program, replaced references to TEDS (Tactical Environmental Data Server) and COAMPS (Coupled Ocean and Atmopshere Model Prediction System) with NWP (Numerical Weather Prediction). Renamed the \data\teds folder to \data\nwp. These changes accommodates the ability of AREPS to not only use COAMPS environmental data but other numerical weather prediction models such as MM5. In addition, these changes accommodates the ability of AREPS to not only obtain NWP model data from TEDS but from other data sources such as the Defense Threat Reduction Agency's (DTRA) Meteorological Data Server (MDS). For our previous uses of these data, you must move any NWP files (those with a .prf file extension) from the \data\teds folder to the \data\nwp folder.

We have found that in NWP data files obtained from the DTRA MDS, certain profile levels are reporting no data. This is indicated by a -9999 in the data field. Modified the AREPS environment program to do an automatic interpolation of the profile data to provide a value for the missing data value.

For the Ionospheric raytrace project, modified the graphics labeling to show values of group delay, phase delay, transmitter elevation angle, and reception elevation angle.

For the Ionospheric raytrace project and the HF communications project, changed the upper limits on the sunspot number.

Version of AREPS is 3.04.1.32 dated 25 April 2005. The following are the new features and modifications to the previous version (3.04.1.31 dated 11 April 2005).
Modified the format of the displayed text when the mouse is moved over the loss versus range/height graphic and performed other cosmetic modifications to improve readability.

Added additional error checking for the import of a HPAC formatted COAMPS environmental data file. This error checking examines the file to insure it contains sufficient data to create a range and bearing dependent environmental file.

Modified the environmental program's custom column input method so that column formatting of the data within the Window's clipboard is retained when these data are pasted into the input window. This removes the necessity of pasting these data into Notepad prior to using them within AREPS.

Modified the WMO decoding routine to remove the error message box for dewpoint depression values from 51 to 55. These reporting numbers are not used by the WMO. However, we have found these numbers appear when synthetic WMO code is created from mesoscale meteorological models. Rather than notifying the operator of an error and requiring him to edit these data, AREPS now assumes the dewpoint depression to be 5.1 to 5.5 degrees Celsius.

Modified the various system windows (platform, radar, etc.) to insure consistancy of display between all windows.

Within the FalconView project, we now automatically adjust the maximum display height to make sure it is always greater than the transmitter's antenna height and the desired display height. This removes an error notification window and allows the FalconView display to proceed without additional operator intervention.

Removed the need to save the FalconView project unless you choose to save the APM binary files for displaying the normal coverage diagrams.

Updated the on-line help to resolve an equation display error for the radar and ESM model. Added the radar and ESM model descriptions to the user's manual.


Version of AREPS is 3.04.1.31 dated 11 April 2005. The following are the new features and modifications to the previous version (3.04.1.28 dated 24 March 2005).
Resolved an error within the Ionospheric raytrace and the AREPS "Lite" projects which caused them not to execute.

Modified a default within the target description should the antenna polarization be "undefined" within an imported EM system database. Any "undefined" polarizations within the database will be set to "horizontal." This should not be an issue for any targets entered into your database using the target editor window of AREPS.

Updated the on-line help and the user's manual to provide an accurate description for the format of the optional APM ASCII text output file.

Version of AREPS is 3.04.1.28 dated 24 March 2005. The following are the new features and modifications to the previous version (3.04.1.25 dated 11 March 2005).
Added a new menu item to the help menu. This item now allows you to connect directly (assuming you have network connectivity) to our on-line new feature and bug report form. This is one more method in keeping the communication channels open between you and us.

Modified all the Save Image options such that you may select a particular graphic file format directly from the save window without having to modifiy the file name.

Restructured the wind file format to allow for multiple bearings.

Removed the GUI inputs for surface wind speed and direction from the standard project window. Surface wind speed and direction are now taken from the atmosphere file you select or from your own wind file created with the wind editor.

Because the ocean surface clutter model is dependent upon wind speed and the frequency of the propagating energy, added a routine to insure winds do not exceed the capability of the model. This will happen automatically without operator notification.

Added an item to the right click menu of the coverage display which allows you to see the actual surface clutter values being calculated by the Advanced Propagation Model. Of course, you may still see these data graphically on the signal-to-noise versus range display in addition to still viewing and saving the actual clutter numbers.

Removed the "clipping" of the tropospheric raytrace graphic. By so doing, the rays no longer stop at the axes boundaries. This allows for the display of the entire ray path for those rays that reach below sea-level altitudes.

Updated the on-line help to reflect changes made to AREPS since the last version.

Version of AREPS is 3.04.1.25 dated 11 March 2005. The following are the new features and modifications to the previous version (3.04.1.21 dated 22 February 2005).
Updated the tropospheric raytrace project to increase execution speed and resolved some minor problems in the GUI interface.

Added a new option to the right-click menu of the coverage display. This option toggles the identification text off and on. This feature is used for declassifying a printed or saved image.

Disabled the GUI inputs for surface wind speed and direction when these data are requested from an environmental file.

Resolved an error in computing gasseous attenuation when values of air temperature and humidity are read from the environmental file. Also changed the default computation method to read the temperature and humidity from a file vice no attenuation.

For Composable ForceNet, modified the AREPS program flow such that the AREPS data is not written into the CFN output file until all the bearing calculations are completed. This resolves an issue with Composable ForceNet trying to retrieve data that is only partially complete.

Version of AREPS is 3.04.1.21 dated 22 February 2005. The following are the new features and modifications to the previous version (3.04.1.16 dated 08 February 2005).
Within the HF communications project,
  • added a world-wide display for maximun usable frequency, frequency of optimum transmission, and lowest usable frequency.
  • added the capability for automatic sky wave calculations when your computer's clock changes time.
  • added a feature to print and save raw calculations data and to display these data in the right panel of the status bar as the mouse moves over the graphic.

Resolved a problem in AREPS' display of surface clutter data returned from the Advanced Propagation Model (APM).

To improve execution speed, compiled AREPS with an advanced feature favoring a Pentium processor.

Updated the on-line help and user's manual to reflect changes made to AREPS since the last versions.

Version of AREPS is 3.04.1.16 dated 08 February 2005. The following are the new features and modifications to the previous version (3.04.01.15 dated 07 February, 2005).
Updated all the projects and decision aids to reflect the effects of surface clutter. For the standard project and all the decision aids that flow from it, surface clutter is an option, selectable from the standard project window. For the FalconView project and all the Composable ForceNet projects, clutter will always be considered if the surface wind speed is greater than zero.

Updated all the projects to take advantage of the undocumented APM feature as implemented in the previous version of AREPS.

Resolved a problem within the coverage display when selecting certain display types in combination with an emitter that is defined as CW or other radar calculation type.

For the area display, restructured the program flow in order to reduce the number of calculations required.

Updated the on-line help to reflect changes made to AREPS since the last versions.


Version of AREPS is 3.04.1.15 dated 07 February 2005. The following are the new features and modifications to the previous version (3.04.01.10 dated 18 January, 2005).
Modified the Composable ForceNet output file to include the effects of surface clutter in the target detection. To detect a target, the signal-to-noise ratio must now exceed both the system detection threshold and the clutter-to-noise ratio. The clutter is automatically computed from the surface wind speed read from the environmental file.

Added the surface clutter to noise ratio data to the optional ASCII text output file.

Implemented an undocumented APM feature which computes propagation loss versus range at a fixed height above the surface. This was done to allow for the extrapolation of propagation loss to a height lower than the lowest APM output height as computed from the project's maximum and minimum height.

Resolved a problem within the automatic Composable ForceNet window so now the proper DTED terrain data are used.

Reduced the lower limit for the project's minimum height to insure the lowest point on the earth's dry land surface is accessable.

Updated the on-line help and user's manual to reflect changes made to AREPS and the environment program since the last versions.


Version of AREPS is 3.04.1.10 dated 18 January 2005. The following are the new features and modifications to the previous version (3.04.01.09 dated 14 December, 2004).
Added a surface clutter line to the propagation signal-to-noise ratio vs range display. The clutter line is activated from the right click menu.

Resolved a problem with surface wind speed when the operator requests surface clutter. If the operator wants surface clutter, the frequency is 1 GHz or greater, and any portion of the propagation path is over water, the operator must enter a wind speed greater than zero.

Resolved a problem when the operator enters his own surface scatter values within the custom terrain file editor. The scatter values are mow read correctly.

Updated the source code error numbers internal to the APM to reflect modifications made to the propagation model.

Changed the public internet and SIPRNET URL addresses to reflect the new values.

Updated the on-line help to reflect changes made to AREPS and the environment program since the last versions.

Updated the environment program to reflect the new "What's this help."

Version of AREPS is 3.04.1.09 dated 14 December 2004. The following are the new features and modifications to the previous version (3.03.01.51 dated 23 September, 2004).
Impleted a new project type called Ionosphere Raytrace, this version of AREPS will install ionospheric model data files in a new data subfolder, called ionosphere. This new project type will support ionosphere HF propagation, both communications and radar.

Restored the tropospheric raytrace project with a completely redesigned algorithm. The new design resolved many problems in altitude error calculations related to terrain intercept angles, shallow sloping refractivity profiles, and certain combinations of ray propagation angle and terrain/refractivity slopes.

Restored the ocean surface clutter model within the Advanced Propagation Model. The model is driven with the surface wind speed entered from the project window.

Created the ability to have AREPS automatically center its windows upon your screen. This prevents windows from spreading across multiple screen displays, both in a vertical and horizontal display sense. In addition, AREPS will remember the window size and placement from your previous use.

Within the custom terrain input method, add the capability of specifying range dependent terrain scatter effectiveness. These values are used in the calculation of terrain clutter.

Within the environment program, removed the capability of connecting to a networked Tactial Environmental Data Server (TEDS) for obtaining COAMPS data and single station observations. The technique AREPS used has become obsolute with the emerging TEDS Services. When TEDS Services becomes operational, AREPS will again take advantage of the new techniques for obtaining observed and modeled environmental data. The ability of using COAMPS environmental data obtained from METOC center's DAMPS homepages remains uneffected.

Modified the Composable ForceNet automatic interface window allowing the operator to select many items from the CFn application itself. Modified the format of the EM system database XML file used by Composable ForceNet application. The file now contains a section of emitters, listed as either radars or radios.

Resolved an error in drawing range rings upon the area coverage display.

Resolved an error in drawing angle reference lines when the angle takes the line below the earth's surface.

Version of AREPS is 3.03.1.51 dated 23 September 2004. The following are the new features and modifications to the previous version (3.03.01.43 dated 18 August, 2004).
Added a new project type called AREPS Lite. This project uses our FFactor propagation model vice the Advanced Propagation Model for calculations. Thus, AREPS Lite is not appropriate for over terrain propagation. However, for over water propagation, the model runs extremely fast and gives very reasonable assessments. Be sure to read the on-line help for this new project type for additional features.

Created a new graphic capability for adding your own annotations to the graphic displays. Annotation items are lines, arrows, rectangles, text, and symbols. In addition to these annotation items, you may change the attributes of the items to include colors, fills, line thickness, arrow head styles, and text attributes such as fonts, bolding, italics, etc. If the graphic is capable of supporting annotation, the annotation toolbar button (it looks like a little pencil) will become active. Clicking this toolbar button will open the new annotation toolbar. This toolbar is designed after Microsoft's PowerPoint toolbar so it should be easy to use and understand without additional training. Be sure to read the on-line help for a complete discussion of this new annotation capability. For this version of AREPS, we have limited the annotation to the coverage display. Subsequent versions will activate annotation for other display.

In preparation for the release of a new project type called Ionosphere Raytrace, this version of AREPS will install ionospheric model data files in a new data subfolder, called ionosphere. This new project type will support ionosphere HF propagation, both communications and radar. It will have many display graphics and data output options. While not active at this time, the on-line help contains a complete description of this new project type. Check it out!

Added a new optional data save feature, found on the Save Optional Data item of the Options menu. This feature will save both APM and terrain data in an ASCII text format, within their own multi-bearing files. This is a custom designed feature (at the request of the US Air Force 84th Radar Evaluation Squadron) to allow for post processing of APM and terrain data within a multi-bearing application.

Added an option to change the background color for the area coverage display when using DTED data. This option is reached by right clicking on display's DTED terrain legend box.

Added microVolts as a unit of power.

Resolved a problem with sizing of check boxes and options buttons when AREPS is run on a wide-screen laptop computer.

Resolved a problem with placing the origin of the angle reference lines upon the coverage display when you change the transmitter height reference between above mean sea-level (MSL) and above ground level (AGL).

Resolved a problem when assessing a CW radar when the surface winds are greater than zero. Prior to the fix, you would receive an error message stating you may not assess your CW radar within a sea-clutter environment. With this fix, you no longer receive the error message.

Version of AREPS is 3.03.1.43 dated 18 August 2004. The following are the new features and modifications to the previous version (3.03.00.38 dated 02 August, 2004).
Modified the Composable ForceNet automatic interface window allowing the operator to select many items that were previously defaulted within the code.

Added an "AREPS on the web" item to the Help menu. Depending upon your network connection, clicking this item will take you to one of our various homepages.

Added two column placeholders within the file that is saved from the "List loss array" window. By doing this, you may import this saved file into Microsoft Excel without having the columns in the first row offset by two.

Version of AREPS is 3.03.1.38 dated 02 August 2004. The following are the new features and modifications to the previous version (3.03.00.35 dated 28 July, 2004).
Implemented an automatic project execution capability when AREPS is being used in association with the Navy's Composable ForceNet system. This feature is only available for registered copies of AREPS and only when AREPS and the Composable ForceNet application are properly communicating with each other. A summary of this capability is described within the on-line help. For detailed information about this capability, please contact technical support.

Version of AREPS is 3.03.1.35 dated 28 July 2004. The following are the new features and modifications to the previous version (3.03.00.34 dated 19 July, 2004).
Resolved an error which prevented the quick action buttons on the main window from reappearing when all other windows are closed.

Added the capability of specifying your own angle for the angle reference lines option upon the coverage display. This option is available from the right click popup menu.

Increased the upper limit for all M-unit inputs from 3000 to 6000.

Modified the AREPS InstallShield installation program to create registry entries for the path to the AREPS executable file and for the AREPS version number. This was done to allow companion programs to recognize the existance of AREPS. These keys are within HKEY_LOCAL_MACHINE/SOFTWARE/Areps

Resolved an error in the Reseach Project which displayed a single bearing error message when using DTED data. This error message will now only occurr if you either enter your own terrain data into the terrain tabular form or read your own terrain data from a file, and select more than one bearing.

Version AREPS is 3.03.1.34 dated 19 July 2004. The following are the new features and modifications to the previous version (3.03.00.32 dated 24 June, 2004).
Resolved an error while drawing upon the FalconView background, both for the COAMPS area and the probabilities of detection. This error caused detection lines to be drawn when the propagation loss was below the detection threshold for heights over terrain.

Resolved an error while drawing upon the FalconView background when the current window is the normal AREPS planned view display. The error prevented the drawing upon the FalconView background.

Modified the project program flow to check for the maximum terrain height on all the bearings, prior to the executation of APM. This insures all the bearings are calculated to the same maximum height. This is a requirement for the Composable ForceNet display but not necessarily for AREPS in general.

Resolved an error while calculating the first level of the environmental height versus M-unit profile if the station elevation was entered prior to importing any other observational data. The error caused the first level height to be zero.

Version AREPS 3.03.1.32 dated 24 June 2004. The following are the new features and modifications to the previous version (3.03.00.31 dated 10 May, 2004).
Added a new capability to create an evaporation duct profile from climatological surface observations. In addition, the statistics for the surface conditions of our Ducting Climatology Summary (DCS) program have been implemented within AREPS. In version 3.03.00.17 dated 27 January 2004, the upperair portion of the DCS was implemented into AREPS. This now completes our integration of DCS into AREPS. Thus, our DCS program is now removed from distribution and will no longer be supported.

Added a new capability to create AREPS output files for display within the Navy's Composable ForceNet system. This feature is only available for registered copies of AREPS. A summary of this capability is described within the on-line help. For detailed information about this capability, please contact technical support.

Modified the code to display AREPS output upon the FalconView map background. This modification was necessary for compatability with the new Map server of Falconview version 3.3.

Resolved an error is displaying "water" color for the DTED maps where the DTED CDs or the data are missing. To display "blue" for these data voids, you must select the proper DTED terrain options.

Redesigned the Font window to make it both easier to use and to offer additional options.

Resolved an error within the environment program such that the Save and Save As menu items now function correctly. Previously, saving an environmental file was always done using the Save As method.

For the environment program, expanded the evaporation duct tabular form to display heights above that of the join height between the evaporation duct profile and the upperair profile.

For the environment program, added addition coloring to better highlight important features.

Modified the on-line help to reflect the above changes.

Version AREPS 3.03.1.31 dated 10 May 2004. The following are the new features and modifications to the previous version (3.03.00.28 dated 14 March, 2004).
Resolves an error in the specification of terrain surface types.

For the coverage display, provides a new option to use either the physical curvature of the earth or a four-thirds curvature of the earth when drawing curved and dual curved earth displays.

For the coverage display, provides a new option to show angle reference lines relative to the antenna elevation angle in addition to the horizontal.

For the coverage display, provides a new option to show slant ranges from the transmitter to the mouse pointer in addition to horizontal ranges.

Added new debugging code that allows us to better track the program flow.

Modified debugging code which writes messages into the EM system database.

Modified the on-line help and user's manual to reflect the above changes.

Version AREPS 3.03.00.28 dated 14 March 2004. The following are the new features and modifications to the previous Beta version (3.03.00.23 (Beta) dated 23 February 2004).
Removed the "Beta" designation

Updated the Advanced Propagation Model.

For a radar emitter, added the capability to describe the radar's function and if the function is approporiate, add a description of an associated weapon. This is prelude to a new tactical display.

For a missile target, added the capability to describe its expected engagement range. This is prelude to a new tactical display.

Added a new progress bar window to show the progress of long execution time functions. For example, when AREPS starts, it reads your EM system database. Should your EM system database contain hundreds (or even thousands) of radars, it may take a number of seconds to read. Rather than just showing the AREPS splash screen and having you wonder if AREPS is "frozen", the window will show the progress of the reading function.

Added a new series of icons that are associated with particular radar functions. These icons are those used by the PFPS program. Thus, when you use the AREPS FalconView display, the radars on the map will be displayed using the PFPS icons. These icons are also used throughout AREPS, particularly when you are using systems obtained from associate application databases.

For the HF project, added the capability of changing the transmitter power and required signal-to-noise "on-the-fly." In addition, added an option of showing only those map areas that have signal-to-noise values below and above your required value.

Within the environment program, modified the height versus M-unit profile tabular form so you may now edit any of the data within the form and recalculate the profile.

Prior to asking for DTED CD-Roms, added the functionality to automatically search for DTED level 0 data should no DTED level 1 data be found

Add mach as a selectable speed unit.

Resolved some problems when working with associate application databases. These problems were primarily related to the time it takes to perform certain AREPS "bookkeeping" functions when the database contains very large numbers of systems.

Resolved a problem in the radar window which would cause AREPS to fail when you toggle between simple and CW radar types.

Resolved a problem with saving display colors within the areps.ini file.

Resolved a problem when drawing a line upon the curved and dual-curved axis display. This problem was related to drawing missile flight profiles.

Modified the on-line help to reflect the above changes.

Version AREPS 3.03.00.26 (Beta) dated 18 March 2004. The following are the new features and modifications to the previous Beta version (3.03.00.23 dated 23 February, 2004).
Added the capability of importing EM system data from associated applications. Refer to the on-line help for a complete discussion of this new feature. Because of the distribution restrictions on these other applications and the classification of these data, this feature is available only to those customers who have a registered version of AREPS.

Modified the target description and EM database to include a dependency of radar cross section upon the elevation and azimuth angles the target presents to the radar.

For missile targets, modified the EM database and added the capability of displaying their flight profiles upon the height versus range coverage display.

Placed a restriction upon displaying altitude errors within the raytrace project. Altitude errors will not be available for over terrain paths. This restriction will be removed in a future version.

Improved the text description of the raytrace graphic when printing it with a printer.

Reworded the Print item text from the File menu to better describe what is to be printed.

Replaced the general purpose data display window with one capable of using colors and various editing features.

Resolved an error in saving custom colors for the height versus range coverage display, both for a default project and an active project.

Resolved an error in relationship between the antenna height units of an emitter, a platform, and a project.

Upgraded all the sample project files to conform to the new project specifications.

Modified the on-line help and user's manual to reflect the above changes.


Version AREPS 3.03.00.23 (Beta) dated 23 February 2004. The following are the new features and modifications to the previous Beta version (3.03.00.22 dated 11 February, 2004).
Added the capability of listing and saving the raw propagation data for the HF communications area display.

For the HF communications decision aid, added the capability of individually saving the various graphic components.

Added the capability of saving the propagation data from the Advanced Propagation Model (APM) in a binary file format readable by our Engineer's Refractive Effects Prediction System (EREPS). The advantage of EREPS is its multiple overlay and file comparison capabilities.

Resolves several errors within the raytrace project dealing with displaying angle reference lines and saving optional output data.

Added a new raytrace project to the main AREPS file menu system.

Resolves a window sizing problem with opening multiple child windows when a previously opened parent window is maximized.

For the communications systems window, deactivated certain input fields not required by the selected antenna type. While the antenna type is properly implemented, there is no reason to ask the operator to provide additional but unnecessary information.

Added an initial check to insure the operator has the necessary folder read/write permissions required by AREPS. If not, a error window is shown, asking the operator to contact the system administrator to grant these permissions.

Modified the on-line help to reflect the above changes.

Version AREPS 3.03.00.22 (Beta) dated 11 February 2004. The following are the new features and modifications to the previous Beta version (3.03.00.17 dated 27 January, 2004).
Added the capability of accepting range and bearing dependent surface winds for the calculation of rough ocean surface. These winds may be created in a custom wind file editor or automatically created within the environmental file generation program for those data input methods that contain wind data. These methods include Custom Column, Metcast/JMV, and COAMPS ingest. The COAMPS ingest method will create the range and bearing dependent winds while the other two methods will create only a single wind speed and direction.

Resolves an error when trying to print an AREPS graphic when you do not have a properly configured printer driver installed on your computer.

Included surface reflected rays in the altitude error display within the raytrace decision aid.

When operating within the Debug mode, added the capability of exporting the APM pathloss data in a binary file format readable by our EREPS program.

Modified the on-line help to reflect all the new features.

Version 3.03.00.17 (Beta) dated 27 January 2004. The following are the new features and modifications to the previous non-Beta version (3.02.06.07 dated 19 August, 2003).
Added a new HF communications project. Because this new feature is so extensive, please read the on-line help that describes this project and all the features of this new capability. This feature required the restructuring of the EM system database, the communication systems editor window, and the radar system editor window. The new database structure is backwards compatable with the previous structure and will not require any modification of the database by the user.

Added a new raytrace project. This raytrace project also has the capability of displaying height-finder radar altitude errors. Please read the on-line help that describes this project and all the features of this new capability. Resolved a number of small errors in the previous beta version's GUI to include proper placement of the angle reference lines.

Reintroduced the surface clutter model to the Advanced Propagation Model. The full AREPS/APM interface for surface clutter will be implemented within the next release of AREPS. This will include the ability to fully define your range and bearing dependent terrain surface characteristics in addition to range and bearing dependent surface wind speeds and directions for ocean clutter. These ocean data are currently available via the same method AREPS uses to obtain COAMPS environmental data.

Expanded the capability and enhanced the user interface of the upperair climatology within the environmental profile creation program. In addition to creating an upperair height versus M-unit profile, you may now view the monthly underlying statistics and a bargraph display of various monthly parameters such as surface-based duct tops.

Implemented a GIS map capability within the environmental profile creation program with regard to the two TEDS LAN data retrieval methods (TEDS COAMPS and TEDS single station observation).

Resolved a number of small problems and added new features since the last non-Beta version of AREPS to include:
  • Added an automatic textbox populate feature to the standard project window. With this feature, an emitter's position may populate the project's position, and if a fixed location receiver is selected, the range and bearing from the transmitter to the receiver will be calculated and the maximum range and first bearing textboxes will be filled. By using this feature, the assessment is made along the exact path from the transmitter to the receiver.

  • Increased the upper limit of surface wind speed from 10 meters per second to 20 meters per second

  • Implemented a new profile extrapolation technique based upon ITU surface refractivity database studies. This new extrapolation technique is set as the default and will resolve troposcatter problems for stations at high altitudes where the first refractivity profile gradient is trapping. The installation now contains the ITU database file that was inadvertently left out of the previous installation package.

  • Added a new data quality routine for DAMPS homepage obtained HPAC COAMPS data in cases where vertical data are randomly missing from pressure, temperature, and humidity profiles. This routine provides a "best" estimate of the missing data and allows for use of the data vice rejecting the profile as previously done

  • Resolved a problem in processing correct environment file within the automode project

  • Resolved a problem with the troposcatter calculation within the Advanced Propagation Model

  • Added new coloring and modified the display of the environmental profiles within the environment creation program.

  • Resolved an error in the conversion of heights between feet and meters after the environmental profile has been created

  • Resolved an error in angle reference line units

  • Restructured the program flow for default and active project options

  • Added the capability of entering a user-defined vertical antenna pattern for VHF and above communication systems

  • Added an optional geographical location and antenna height association for each emitter. This provides more flexibility in the use of AREPS without having to create and rely upon platform definitions

  • Modified the year in the About window to 2004 vice 2003

  • Modified the on-line help and user's manual to reflect all the new features


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Updated: 3/31/2011 11:09 PM EST   Published (1.0)