Keeping UAVs Under Control During GPS Jamming

Unmanned aerial vehicles (UAV) are being more and more widely deployed. Although, initially most UAVs were controlled by a pilot, autonomy has increased. This requires the flight controller in the UAV to accurately know the current system state. Knowing the current position is of crucial importance. Fortunately, this can be reliably obtained from a global navigation satellite system (GNSS) receiver. Recently, it was shown that criminal GNSS jamming frequently occurs. First, this paper analyzes the risk posed by off-the-shelf civilian GPS jammers to UAVs. Then, as the main contribution of this paper, a countermeasure is described and implemented using custom hardware and software that allows the control radio to be used as a backup navigation source. Finally, the proposed solution is tested in ideal and field conditions. It is shown that good performance can be obtained by the presented system, almost without additional system cost.