Autonomous Communication Relays for Tactical Robots

The high-bandwidth digital radio link between a mobile robot and its remote control station degrades quickly as the robot penetrates the interior of a building or becomes shielded by intervening terrain. This paper describes a current project that uses mobile autonomous communication relay nodes to overcome this problem. Each node is a small slave robot equipped with sonar, ladar, and 802.11b-based ad hoc networking radio. The relay robots follow the lead robot and automatically stop where needed to maintain a solid communication network between the lead robot and the remote operator. With their onboard external sensors, they 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 catch up to the lead robot and be reused, using maps generated by the lead robot. All relay deployment and redeployment functions occur without the operator's awareness.