Hybrid Integration and Detection of Moving Target With Moderately Fluctuating Rayleigh RCS for Low Earth Orbit Navigation Augmentation Signal‐Based Passive Radar

ABSTRACT

Passive radar (PR) based on existing spaceborne illuminators has significant advantages including emission‐free operation, low cost and high security. It can detect the target independently or serve as a complementary sensor to active radars. This paper investigates the moving target detection under the low earth orbit navigation augmentation (LEO‐NA) signal‐based PR (LNAS‐PR) system, which utilises the LEO satellite with navigation augmentation capability as the illuminator. However, the motion of the LEO satellite illuminator, receiver and target makes the geometric structure of the LNAS‐PR detection scenario constantly change. During the long‐time observation, the radar's observation angle varies with time, then, the target's radar cross‐section (RCS) will exhibit a moderate fluctuation. Therefore, this paper studies the detection for moderately fluctuating Rayleigh targets under the LNAS‐PR system. By jointly considering the target's motion and electromagnetic scattering characteristics, this paper proposes a novel detection algorithm based on quadratic phase compensation (QPC), Keystone transform (KT) and hybrid integration (HI), which is named as QPC‐KT‐HI algorithm. First, the range cell migration (RCM) and Doppler frequency migration (DFM) caused by target motion are corrected through QPC and KT. Moreover, utilising the target's scattering characteristics, the HI is performed to accumulate the target energy, thereby achieving target detection. Finally, the effectiveness and advantage of the QPC‐KT‐HI algorithm are verified by three simulation experiments.