Track-Before-Detect Technique in Mixed Coordinates

Conventional track-before-detect (TBD) usually considers remote target with constant Cartesian velocity following an approximate straight line motion in sensor coordinates. This model inaccuracy may lead to integrated energy loss especially in near scenario. In this paper, a multi-frame TBD technique in mixed coordinates (MC-MF-TBD) is proposed for weak target detection and tracking in non-Cartesian sensors. Predicted position of a cell in sensor coordinates is obtained by converting Cartesian-coordinate predicted position, achieved according to an assumed velocity in a Cartesian frame, back to sensor coordinates. Then, measurement of each cell is added onto the cell closest to the predicted position to realize energy integration. The procedure of multi-frame accumulation in mixed coordinates is derived in detail. To match the unknown target velocity, a mixed-coordinate-based velocity filter bank is presented and the filter mismatch loss is investigated. Simulation results demonstrate the superiority of MC-MF-TBD compared with other MF-TBD strategies.