Research On ISAR Imaging Method Of Targets With Complex Motion Based On Parameter Estimation

The Inverse Synthetic Aperture Radar(ISAR)technique,which has wide-ranging application,can obtain comprehensive information,such as shape,structure,spatial location and motions parameters,of targets with complex motions.The targets with complex motions are widely distributed in practical application.The echo signal of targets with complex motions can be established as a Cubic Phase Signal(CPS)model after the radar echo motion compensation process.The signal processing method of the cubic phase signal model is the basis of ISAR imaging of complex moving targets,which determines the quality of ISAR imaging.This dissertation has done some researches in the ISAR imaging method of complex moving targets based on parameter estimation,the main contents are summarized as the following three points: 1.According to the characteristics of radar echo signals,the ISAR imaging model of complex moving targets is introduced.The echo data of complex moving targets,after motion compensation,can be described by CPS model.The CPS model parameter estimation is a crucial step of the ISAR imaging method.This dissertation introduces some classic parameter estimation algorithms.2.For complex moving targets,an ISAR imaging algorithm based on Non-uniformed Sampled Integrated Modified Chirp Rate-Quadratic Chirp Rate Distribution(NIM-CRQCRD)is proposed.NIM-CRQCRD improves the anti-noise performance by using a combination of non-coherent accumulation and coherent accumulation,and the implementation process only requires complex multiplication and Fast Fourier Transform(FFT)operations.In this new non-search algorithm,there is no need in the tedious parameter search process and the use of Non-uniform Fast Fourier Transform(NUFFT).The results of simulation experiment prove the superiority of the algorithm in anti-noise performance.3.For complex moving targets,an ISAR imaging algorithm based on Coherently Integrated Non-uniform Trilinear Autocorrelation Function(CINTAF)is proposed.CINTAF defines a new Non-uniform Trilinear Autocorrelation Function(NTAF).NTAF can achieve coherent accumulation of signal energy in the two-dimensional data domain with slow time-delay and improve the anti-noise performance of CPS parameter estimation.Based on the performance analysis and simulation verification of the CINTAF parameter estimation algorithm,an ISAR imaging algorithm based on CINTAF is proposed.The simulation experiment results verify the advantages of the ISAR algorithm in terms of calculation and anti-noise performance.In summary,the results of this research prove that the ISAR imaging algorithm proposed in this paper,improving the anti-noise performance with low calculation amount,can obtain the ISAR imaging of complex moving targets with higher resolution results.