Journal of Radars (雷达学报) 2013/2:4 PP.430-438
For passive radar, a long integration time is used to achieve high processing gain in order to detect a weak target. As a result, range migration and Doppler expansion may occur for high-speed targets. A keystone transform can be used to rectify range migration introduced by radial velocity. Tangential velocity, however, may lead to Doppler expansion, which entails a loss of integration gain. In this paper, a signal model is presented to analyze the reason for Doppler expansion. A Doppler expansion compensation method is then introduced based on a RSPWVD–Hough transform for a multiple-target scenario. Simulation results show that the proposed method can compensate, with good performance, for the energy loss caused by Doppler expansion in a multiple-target scene. Additionally, results show that the proposed method is also effective for weak targets, and may therefore improve the ability to detect weak targets in passive radar systems.