Passive tracking of the moving object by UHF beyond-the-horizon three position bearing system

The problem of a moving illuminating target coordinates estimation using the results of bearing measurements performed by the three separated in space moving bearing systems is discussed. The target is beyond-the-horizon at a distance of up to 250-350 km long, its antenna works in the regime of lobe scanning in the plane of the measured angle. The conditions of UHF wave propagation and the peculiarities of passive bearing systems operation cause gaps in the measured samples at each point and abnormal angle measurements (with error bigger than normal). Optimization of the coordinates estimation algorithm means adaptation to these phenomena. RMS errors for distance and angle measurements produced by an adaptive dynamic filter using an extended Kalman filter algorithm are shown.