Data exfiltration from unattended ground sensors using cooperating UAVs

Advances in networking, communications, and sensor technology have made it possible to deploy networks of spatially-distributed sensors to provide tactical or security forces with critical operational intelligence. Many application arenas have requirements for low-power, long-life sensors and stand-off for operations personnel, dictating the need for socalled unattended ground sensor networks (UGS). However, often the environment (e.g., an urban environment) limits communication capabilities. To solve this problem, in this paper we propose the use of multiple, cooperating unmanned aerial vehicles (UAVs) to collect, or exfiltrate, the data from the UGS. In our scenario several prototype sensor clusters are deployed in relatively unknown locations, with a limited communication range. Each cluster's dedicated base/bridge node communicates via an IEEE 802.11b wireless link. The UAVs execute a cooperative flight pattern to first find the sensor clusters, to then collect their data, and to relay that data to a ground station. Throughout the process, the UAVs cooperate autonomously to achieve the goal, reconfiguring as needed in response to changes in the mission, in the targets (sensors), or in the available resources (the UAVs themselves). In the paper we describe our approach to cooperative behavior, our aircraft, and some preliminary experimental results.