3D AOA/TDOA emitter location by integrated passive radar/GPS/INS systems

3D passive geolocation of radar emitters is an important problem in electronic support for military surveillance. The angle of arrivals (AOA) and time difference of arrivals (TDOA) are two popular schemes for passive emitter location. In this paper, a location scheme is proposed based on fusion of AOA and TDOA measurements from two electronic support measures (ESM) sensors installed on two moving platforms, respectively. The sensor positions, velocities, and platform attitudes are estimated by loosely-coupled GPS/INS systems. AOA and TDOA measurement equations are formed by AOA and the time of arrivals (TOA) measurements of the ESM sensors and the platform positions and attitudes. Least-squares (LS) is proposed to fuse AOA measurements from two ESMs, and its estimation is used as the initialization of the iterative LS (ILS) method for fusing both AOA and TDOA measurements. Experimental results show that the location accuracy of the radar emitter can be improved effectively by this AOA/TDOA fusion method.