SSC Pacific
Communication Relays: MDCR



In late FY10 we received a request from the Naval Explosive Ordnance Disposal Technology Division (NAVEODTECHDIV), responding to two Joint Urgent Operational Need Statements from US Central Command, to provide a relay system for evaluation at the Joint Counter-IED Facility at the Naval Air Warfare Center in China Lake, CA. We provided two repackaged relay nodes (the automatic deployment capability was not required), which were tested along with several other solutions from other laboratories and commercial vendors. Our system was picked for further development. Subsequently, with funding from the Navy Expeditionary Combat Branch (OPNAV N857) and managed by NAVEODTECHDIV, we designed and built 15 prototype MDCR kits for operational assessment at Fort Leonard Wood, MO, and in Afghanistan. Five kits each were built for the iRobot 500 PackBot, 510 PackBot/FasTac, and 310 SUGV/MiniEOD. (A prototype system was also developed for the QinetiQ Talon robot as part of the initial evaluation but was not selected for further development. This Talon system used the same relay nodes as the PackBot systems, and all robots and their relays would operate in the same mesh network.)

After the prototype systems passed the operational assessments, we were tasked to develop a level-III (production) technical data package (TDP) and two end-of-line test fixtures for semi-automated functional verification of production units as they exit production lines. Using this TDP, the Robotic Systems Joint Project Office fielded 243 kits in Afghanistan in the second half of 2012, built by the Tobyhanna Army Depot.

Each MDCR kit includes two ruggedized relay nodes, to be carried and deployed using deployment forks attached to the flippers of the robots, end- point radios for the robots and OCUs, and miscellaneous hardware and manuals (see Figure 5). The MDCR relay nodes are waterproof and use standard military BB-2557 rechargeable batteries. The radios used are compatible with coalition Counter-Remotely-controlled-IED Electronic Warfare (CREW) jammers. The antennas are flexible and foldable. (Earlier prototype antennas were not foldable and proved to be a weak point in the system.) Each deployment fork was designed to connect to and disconnect from the robot flipper with the use of a quick-release pin. An angular attachment offset between the forks allows the relay nodes to be deployed and picked up one at a time (see the left image in Figure 5).

Each relay node has an LED indicator that tells the operator through its solid or blinking status whether the unit is offline, in the mesh network, or is trying to join the network. The Babel-based ad hoc networking software developed and optimized for teleoperation during the third-generation ADCR effort was used without the automatic deployment function. The entire system was designed to be plug-and-play on each type of robot it was built for—no modification of the robot or controller software was required.

MDCR relays carried by an iRobot 510 FasTac. An MDCR kit
Figure 5. MDCR relays carried by an iRobot 510 FasTac (left) and an MDCR kit (right).

For further information, see:

  • Nguyen, H., Pezeshkian, N., Hart, A., Burmeister, A., Holz, K., Neff, J., and Roth, L., "Evolution of a radio communication relay system", SPIE Proc. 8741: Unmanned Systems Technology XV, Baltimore, MD, May 1-3, 2013. 
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Updated: 7/15/2013 10:20 AM EST   Published (1.0)