Emitter localization based on angle of arrival measurements using digital terrain elevation data

In this paper, passive localization of an emitter by using its estimated azimuth and elevation angles, with a single moving platform is analyzed. Beyond angle of arrival measurements, the distance between target and platform is estimated by using stored digital terrain elevation data (DTED) and a better performance is achieved compared to the direction-finding (DF) only method. Location estimates found by different DF lines are combined by minimizing a defined cost function. Since this problem has not a closed-form solution, two different search algorithms are used: grid search and particle swarm optimization (PSO). Speed and performance of these two algorithms are compared. After initial position of the target is estimated, with a new measurement (azimuth and elevation angle), and the estimated distance information by using these measurements, target position is updated with Kalman filter.