Space Maneuvering Target Integration Detection and Parameter Estimation for a Spaceborne Radar System With Target Doppler Aliasing

Space maneuvering target detection and parameter estimation are the challenging problems in a spaceborne radar system. The complex motion of an observed target usually leads to the range migration (RM) and Doppler frequency migration, causing the difficulty in target detection. Furthermore, the relative high speed of space maneuvering target and limited pulse repetition frequency will result in Doppler ambiguity, further degrading the target detection performance. In this article, a novel and efficient coherent accumulation algorithm is proposed, which considers the velocity ambiguity and Doppler aliasing caused by the target radial velocity and acceleration, respectively. In the proposed method, the target radial velocity and acceleration are first separated by applying the time reversal transform technique. Then, the target radial velocity is estimated by using the Keystone transform. After compensating the velocity effects, the frequency reversal transform is proposed to remove the residual RM, and the acceleration estimation can be efficiently accomplished by the nonuniform fast Fourier transform. Compared with the conventional coherent integration methods, the proposed method can be suitable for the motion parameter estimation and coherent integration detection for a maneuvering target with velocity ambiguity and spectrum aliasing. Additionally, the proposed method is computationally efficient since only the complex multiplication and fast Fourier transform calculations are involved. Both simulation experiments and measured data results are provided to verify the effectiveness of the proposed algorithm.