Complex migration correction and coherent integration algorithm for radar target with arbitrary moving direction

Long-time coherent integration is conducive to improving the radar detection performance for weak moving targets, whereas range migration (RM) and Doppler frequency migration (DFM) might occur when the target has high speed and high maneuverability. Although a variety of methods have been proposed to correct RM and DFM, they are widely based on the target's radial motion model, which is expressed as a finite order polynomial with respect to slow time. However, when an offset exists between the target's moving direction and radar sight line, model mismatch will occur and deteriorate the integration performance. In this paper, the accurate echo model for the moving target with arbitrary moving direction is established, then the modified Radon Fourier transform (MRFT) algorithm is proposed to realize coherent integration via removing the complex RM and DFM. Moreover, the generalized form of MRFT, i.e., modified generalized RFT (MGRFT), is introduced to focus the target with high maneuverability. Both simulation and real data processed results have been provided to validate the effectiveness of the proposed method. According to the coherent integration results for the target with oblique maneuvering motion, the signal-to-noise ratio (SNR) gain of the proposed method is about 4.5 dB higher than that of the existing GRFT method with the same computational complexity.