Research On Coherent Integration Method For High-speed Moving Targets

The long-time coherent integration technique can effectively improve the radar detection capability and parameter estimation accuracy by increasing the integration time.However,due to the high speed and high mobility of the target,the range migration and Doppler frequency migration(expansion)of the echo signals are generated in the process of coherent integration.In order to obtain better target integration performance and parameter estimation accuracy,it is necessary to eliminate the influence of velocity and acceleration on the range migration and Doppler frequency migration in the echo signals.In this paper,the coherent integration technology of high-speed moving targets is studied,and the signal characteristics analysis and signal processing method research are carried out for the problems of echo range migration and Doppler frequency migration of moving targets with uniform and uniform acceleration,including:Aiming at the problem of range migration of uniformly moving targets in coherent integration.,The first-order Keystone transform coherent integration algorithm is studied..For the Doppler ambiguity problem of the algorithm,a method of ambiguity number estimation based on Radon transform is presented and simulated..The experimental results show that the method is effective for the ambiguity number estimation.At the same time,the coherent integration algorithm of Radon-Fourier transform is studied.For the problem of false alarm caused by blind speed sidelobe in this algorithm,the blind speed sidelobe suppression method based on windowing is improved and simulated.The simulation results show that the proposed method can effectively suppress blind speed sidelobe.At last,the advantages and disadvantages of the two methods are summarized.7Aiming at the problem of range migration and Doppler frequency migration of uniformly accelerated moving target in coherent integration,a coherent integration algorithm based on SKT-SIAF-MSCFT was proposed.The algorithm eliminated second-order range migration by performing second-order Keystone transformation on the echo signals in the range frequency domain.Then,SIAF-MSCFT is carried out on the processed signals,which corrects the first-order range and Doppler frequency migration in the echo signals,and realizes the coherent integration and parameter estimation of the signals.Finally, through the experimental simulation and calculation analysis,it can be obtained that the proposed algorithm can obtain higher integration gain in the case of lower computational amount and realize coherent integration of echo signal because the target motion parameters are estimated by non-parametric search.Aiming at the problem of the coherent integration of high-speed moving target.A coherent integration algorithm based on TRT-SKT-FRFT is proposed.This algorithm eliminates the first-order range migration of the echo envelope by performing TRT processing on the signals,and the remaining second-order range migration is corrected by the second-order Keystone transform.After the echo signals are located in the same range unit,the echo data of the range unit is extracted and FRFT is used to estimate the target motion parameters,and then a phase compensation function is constructed to correct the Doppler frequency migration,and the multi-target cross term is analyzed.Finally,the simulation and computation analysis are carried out,the results show that the proposed algorithm can effectively achieve the coherent integration of target signal energy and motion parameter estimation.Compared with GRFT algorithm,the calculation amount of the proposed algorithm is greatly reduced and there is no blind speed sidelobe problem,which is easy to be implemented in engineering.