Ground target position estimation in passive location

Ground target tracking is difficult and actual problem. Because of the high target density and maneuverability, high clutter, low visibility due to terrain masking, etc., ground target tracking presents unique challenges that does not present in tracking of other targets types. But many tracking approaches have been developed for air targets and they work poorly for ground targets tracking. This article includes research work results in radar position estimation for passive range-difference location. Radio source is stationary and performs circular scan. Transmitted signal is received in three points. But beside true measurements of time difference of arrival (TDOA) there are false measurements originated by clutter. Usually clutter measurements are modeled as independed identically distributed. But real experimental data processing shows that in crosscountry its distribution may be multimodal. Therefore standard tracking algorithms are not efficient in this situation. Multimodal distribution is caused by re-reflected signal from underlying terrain. Some ground objects re-reflect signal and imitate additional (false) targets. We propose special approach to decide position estimation problem in such high clutter environment and verify it on experimental data