改进的NLCS星弹双基SAR俯冲前视成像算法OACSTPCD

In diving stage,due to the acceleration of the missile,the amplitude and direction of velocity change sharply and the slant range becomes complicated,which leads to serious range-azimuth coupling and the space variance of Doppler phase.If the azimuth focusing compression is carried out directly,the image must be distorted.To address these two challenges,a modified Nonlinear Chirp Scaling(NLCS)algorithm is applied to the new spaceborne-missile bistatic system model.Firstly,the spaceborne-missile bistatic system model is established.Then,a two-dimensional(2D)spectral expression is derived by using the method of series reversion.In the 2D frequency domain,the effects of range-azimuth coupling are eliminated by completing range compression and migration correction,and the modified NLCS algorithm is used to compensate the azimuth frequency modulation rate to solve the space variance of Doppler phase problem,complete azimuthal compression focusing,and get good imaging results.Compared with the improved Range Doppler(RD)algorithm,the proposed algorithm reduces 1.013×108 floating point operations per second(FLOPS),the azimuthal focusing effect of edge points has been greatly improved,and the peak sidelobe ratio(PSLR),integrated sidelobe ratio(ISLR),and resolution are improved by 2.41 dB,1.29 dB,and 1.16 m,respectively,which proves the effectiveness and feasibility of the proposed method.