Research On Track-before-detect For Medium Pulse Repetition Frequency Radars

Medium pulse repetition frequency(PRF)mode is conceived as a means of improving the radar's ability to contend with main-lobe clutter and ground moving targets(GMTs),so it is widely used in military fields such as fighters.However,with the continuous development of modern technology,radars are faced with severe challenges for accurate detection and tracking.An effective method is to use physical means such as increasing the radar's transmitting power.Another method is to use the multi-frame track-before-detect(MF-TBD)algorithm to perform effective accumulation of weak target energy from the algorithm level.The multi-frame track-before-detect(MF-TBD)algorithm is a technique that can effectively deal with the weak target tracking problem.In the multi-PRF radar system,due to the range and Doppler ambiguities,the state space and measurement space of the target are no longer satisfied with the one-to-one relationship.Therefore MF-TBD cannot be directly applied to the scenario.Consequently,how to realize the detection and tracking of weak targets in the multi-PRF radar system and minimize the complexity of the algorithm is an urgent problem to be solved.In this paper,we study the MF-TBD algorithm for the tracking problem of weak targets in the multi-PRF radar system under range and Doppler ambiguities,the details are as follows:1.For the ambiguous measurement obtained under the multi-PRF radar system,the problems and difficulties of the traditional method are analyzed.An MF-TBD algorithm for point disambiguation is proposed,named as track before detect based on point ambiguity resolution(PAR-TBD).The method can reduce the first threshold and de-ambiguity as much as possible,and utilize the MF-TBD to suppress the false alarm and achieve effective tracking of the weak target.2.Aiming at the high complexity of the PAR-TBD algorithm,a short track sequence disambiguation MF-TBD algorithm is proposed.And for the algorithm,named as joint disambiguation of plot-sequences track-before-detect(JDPS-TBD),a cross-boundary search criterion is proposed to reduce its complexity.The algorithm can effectively track the weak targets and greatly reduce the complexity of the algorithm.3.Aiming at the problem that the low utilization of target potential energy in the PAR-TBD and JDPS-TBD algorithm,a multi-PRF multi-frame track-before-detect(MPMF-TBD)algorithm of disambiguation is proposed.By introducing the range and Doppler folding factor,the inter-frame integration is realized.And the joint accumulation of the multi-PRF measurement data in the frame greatly improves the detection performance of the algorithm.The above proposed algorithms have been proved through the simulation experiment and completed the performance comparison with the traditional method,which proves the effectiveness of the proposed methods.