Maintaining a solid radio communication link between a robot entering a building and an external base station is a well-recognized problem. This has been documented by various sources for diverse applications, from Special Operations Forces' tactical operations in urban terrain to Law Enforcement applications. Modern digital radios, while affording high bandwidth and Internet-protocol-based automatic routing capabilities, tend to operate on line-of-sight links. The communication link degrades quickly as a robot penetrates the interior of a building.
This project, funded by DARPA/IPTO, demonstrates intelligent use of autonomous mobile radio-frequency (RF) repeaters as a solution to this problem. The robot would automatically deploy mobile repeaters (which are slave robots with RF relays convoying behind it) at strategic locations as it penetrates the building interior. With their on-board external sensors, the relay robots also act as rearguards to secure areas already explored by the lead robot. As the lead robot advances and RF shortcuts are detected, relay nodes that become unnecessary will be reclaimed and reused, all transparent to the operator. This would extend the system's range and allow the exploration of larger spaces using the same amount of resources.
In 2004, this project transitioned from research to a more practical application, the JGRE-funded Automatically Deployed Communication Relays (ADCR) project.