A complex pseudo-spectrum based velocity filtering method for track-before-detect

摘要

Velocity filtering based track-before-detect (VF-TBD) has advantages in energy integration and multi-target processing. However, in existing VF-TBD methods, real-valued measurements are used to be accumulated rather than complex-valued measurements. This results in significant waste of information and may degrade algorithm performance, since the phase of measurement is discarded. In this paper, a complex pseudo-spectrum (CPS) method is proposed for VF-TBD to improve the performance of weak target detection, based on the utilization of phase information during energy integration. Firstly, a CPS is constructed around the predicted position of each quantized cell with its complex-valued measurement. Samples of the CPSs from the same frame are added onto corresponding cells to obtain intraframe integrated spectrum, where the target echo values sampled on different cells in a frame have the same phase while noise measurement carries random phase, and the phase diversity is used to improve the performance of energy integration. This procedure can be regarded as coherent integration performed intraframe, contributing to improved integration efficiency. Then, amplitude values of the intraframe integrated results from all frames are added to the integration frame to achieve interframe energy integration. The theoretical detection threshold and receiver operating characteristic curve of the proposed CPS based method in complex Gaussian noise are derived in detail. Theoretical analyses and simulation results are provided to demonstrate the superiority of the proposed method.