Approach for space-based radar manoeuvring target detection and high-order motion parameter estimation

The detection of manoeuvring target for space-based radar is a challenging task because of its weak energy and manoeuvring motion. Prolonging the integration time is an effective method to increase signal energy, which can improve the target detection performance. However, with the increase of integration time, the radial velocity, radial acceleration and radial acceleration rate of manoeuvring target will induce linear range walk, quadratic-range curvature, cubic-range curvature and Doppler frequency migration of echo signal, which may degrade the performance of target detection. To solve this problem, a novel method is proposed that implements a parameter separation transform to isolate the acceleration. Then, the velocity and the acceleration rate can be obtained via one-dimensional search after the compensation of linear and cubic-range migration based on Hough transform and third-order Keystone transform. The kernel steps are as follows: (i) the acceleration is isolated by multiplying the range-compressed data in range frequency domain by its time-reversed data according to the symmetrical property of azimuth slow time; (ii) the cubic-range curvature is corrected by a third-order Keystone transform. The simulation results demonstrate the effectiveness of the proposed method in estimating radial velocity, radial acceleration and radial acceleration rate of a manoeuvring target, thereby the signal energy can be finely accumulated.