Minimum time UAV pursuit of a moving ground target using partial information

The optimal control of a “blind” UAV searching for a target moving on a road network and heading at a known speed toward a set of goal vertices is considered. To aid the UAV, some roads in the network have been instrumented with Unattended Ground Sensors (UGSs) that detect the target´s passage. When the UAV arrives at an instrumented node, the UGS therein informs the UAV if and when the target visited the node. In addition, the UAV can choose to wait/loiter for an arbitrary time at any UGS location/node. At time 0, the target passes by an entry node on his way towards one of the exit nodes. The UAV also arrives at this entry node after some delay and is thus informed about the presence of the target/target in the network, whereupon the chase is on - the UAV is tasked with capturing the target. Because the UAV is blind, capture entails the UAV and target being collocated at an UGS location. If this happens, the UGS is triggered and this information is instantaneously relayed to the UAV, thereby enabling capture. On the other hand, if the target reaches one of the exit nodes without being captured, he is deemed to have escaped. For a given initial delay, we compute the pursuit policy, if it exists, that achieves capture in minimum time, under worst-case target actions.