Research On Long-time Coherent Integration Technology For Aerial Maneuvering Targets

Aerial maneuvering targets are the most flexible,fast and unpredictable among the numerous radar targets.Thus,their detection has always been the research focus of scholars all over the world.With the development of aviation technology,radar cross sections of aerial maneuvering targets have been greatly reduced,making their echo signal energy unable to meet the detection requirement.It is a great challenge for modern radar system.Long-time coherent integration technology can improve the target echo signal energy by extending the observation time,which is one of the effective ways for aerial maneuvering target detection.However,during the observation time,target’s maneuverability may cause range cell migration and Doppler frequency migration.In order to achieve long-time coherent integration,these problems must be addressed.This dissertation conducts in-depth research on long-time coherent integration technology for aerial maneuvering targets.The main research contents are as follows:1.According to the detection scene of the aerial maneuvering target,the echo signal model is established,and the causes of range cell migration and Doppler frequency migration are analyzed.The principles of six long-time integration algorithms are studied,and their theoretical performances are analyzed and compared,including: coherently integrated cubic phase function algorithm,parameterized centroid frequency-chirp rate distribution algorithm,Wigner-Hough transform algorithm,coherently integrated parameterized ambiguity function(CIPAF)algorithm,hybrid integration(HI)algorithm and subspace HI algorithm.They support the research of the full dissertation.2.In view of traditional algorithms’ shortcomings in integration performance and computation complexity,a novel parameterized range-velocity-acceleration distribution(PRVAD)algorithm is proposed.The proposed algorithm utilizes the position of the auto-term energy plane,eliminates the second-order term of the slow time variable by dechirp processing,and achieves coherent integration in PRVAD space.The proposed algorithm can cope with multi-target scenario,and reach an acceptable compromise between integration performance and computation complexity.Both simulation and measured data processing results show that the proposed algorithm is an effective long-time coherent integration algorithm for aerial maneuvering targets.3.In view of PRVAD algorithm’s shortcoming in computation complexity,a novel parameterized velocity-acceleration distribution(PVAD)algorithm is proposed.The proposed algorithm utilizes the position of the auto-term energy surface,achieves coherent integration in CIPAF space and PVAD plane by three-dimensional CIAPF processing and matched filtering processing,respectively.The proposed algorithm can cope with multi-target scenario.Compared with PRVAD algorithm,the proposed algorithm reaches comparable integration performance with lower computational complexity.Both simulation and measured data processing results show that the proposed algorithm is an effective long-time coherent integration algorithm for aerial maneuvering targets.4.In view of PRVAD and PVAD algorithms’ shortcoming in integration performance,a novel subaperture joint coherent integration(SJCI)algorithm is proposed.The proposed algorithm divides the target echo signal into several subapertures,performs coherent processing within and among the subapertures,and achieves full coherent integration in SJCI space.In view of SJCI algorithm’s shortcoming in sampling error,the ideas of parameter subspace division and translation are introduced,and a novel subspace SJCI algorithm is proposed.The proposed algorithm can cope with multi-target scenario.Compared with PRVAD and PVAD algorithms,the proposed algorithm reaches higher signal to noise ratio improvement factor and anti-noise performance with relatively low computation complexity.Both simulation and measured data processing results show that the proposed algorithm is an effective long-time coherent integration algorithm for aerial maneuvering targets.