Targets Detection And Tracking In Wideband Radar

Compared with the narrowband radar,wideband radar has lots of advantages in many aspects.For example,wideband radar can obtain more information about targets and environment,more accurate location of targets and stronger immunity to active and passive interference.Thus,the research on wideband radar signal processing is very valuable in both theoretical analysis and engineering applications.This thesis is addressed on the target detection and the target tracking in wideband radar signal processing.The target detection includes distance measurement and angle measurement.This thesis analyzes and researches its basic theory and technology.The main content of this thesis can be summarized as the following:1.The coherent accumulation in wideband condition is studied.For wideband radar,range migration of target echo exists among different pulses.If the coherent accumulation is performed directly,there will be accumulation loss.Therefore,it is necessary to align the envelopes of echo signals before the coherent accumulation.Keystone algorithm is adopted to correct the range migration,this thesis introduces two specific implementations of the keystone algorithm,and validates its effectiveness to range migration correcting through simulation.Meanwhile,the simulation validates the effectiveness of coherent accumulation under different pulse accumulation multiples in the case of low SNR;If there is the problem of Doppler ambiguity,appropriate fuzzy number compensation is required.2.A fast algorithm of targets echo signal coherent accumulation based on subband processing is studied.Firstly,based on the characteristics of wideband radar targets echo signal,the necessity and effectiveness of coherent processing in the subband domain is discussed;The wideband echo signal is divided into a series of subbands,in each subband,coherent accumulation is performed separately to get the reconstruction echo signal;The decomposition and synthesis of the wideband echo signal is achieved by a DFT modulated filter bank,and a filter bank with good reconstruction performance is designed.From the perspective of computational complexity,the efficient and direct forms of the filter bank are compared;At last,the reconstruction performance of coherent accumulation in each subband is proved by the results of simulations,and based on the degree of range profile distortion and improvement of the SNR,the oversampling subband processing algorithm studied in this chapter is compared with the coherent processing algorithm in Chapter 2.3.The monopulse angle measurement algorithm and the extended target tracking algorithm based on wideband radar are studied.When monopulse is performed in wideband condition,there is a problem of angular glint,thus a monopulse angle measurement algorithm based on the wideband radar signal is studied.According to the monopulse angle measurement,the position information is obtained through the one-dimensional range profile of sum channel,and the angle information is obtained by normalizing the sum channel and the difference channel.Compared to the traditional point target tracking,extended target tracking has better tracking performance.The extended target tracking algorithm is based on the traditional nonlinear tracking algorithm.For extended target tracking algorithm,extended information of the target are added to the state vector to establish the distance expansion model of the extended target.This thesis compares UKF-based extended target tracking algorithm with CKF-based extended target tracking algorithm,and the CKF-based extended target tracking algorithm is proved to have better performance.