  This paper jointly optimizes the flying location and wireless communication
transmit power for an unmanned aerial vehicle (UAV) conducting covert
operations. This is motivated by application scenarios such as military ground
surveillance from airborne platforms, where it is vital for a UAV's signal
transmission to be undetectable by those within the surveillance region.
Specifically, we maximize the communication quality to a legitimate ground
receiver outside the surveillance region, subject to: a covertness constraint,
a maximum transmit power constraint, and a physical location constraint
determined by the required surveillance quality. We provide an explicit
solution to the optimization problem for one of the most practical constraint
combinations. For other constraint combinations, we determine feasible regions
for flight, that can then be searched to establish the UAV's optimal location.
In many cases, the 2-dimensional optimal location is achieved by a
1-dimensional search. We discuss two heuristic approaches to UAV placement, and
show that in some cases they are able to achieve close to optimal, but that in
other cases significant gains can be achieved by employing our developed
solutions.
