Emitter Geolocation with Multiple UAVs

Geolocation of radar and communication emitters based on time difference of arrivals (TDOAs) can be carried out using a network of three or four unmanned aerial vehicles (UAVs) each of which is equipped with an electronic warfare support (ES) sensor, a global positioning system (GPS) receiver, a precision clock and a limited bandwidth communication system. When the leading edge of an electromagnetic pulse is detected by an ES sensor on board a given UAV, the time of arrival and the UAV´s location are transmitted to a fusion centre. The received measurements from all UAVs within the network are then cross-correlated to determine the time difference of arrivals from which emitter location can estimated. This paper presents two sets of emitter location estimation equations. The first set is for 2-D emitter location estimates for a ground based emitter given time of arrival measurements from three netted UAVs. The second set is for an emitter that is locate at an altitude and gives the complete 3-D location estimation equations given measurements from four netted UAVs. Numerical results based on three and four UAVs are presented to validate these equations