LAUSR

Ship target detection using radar is an important application in military and civilian fields. For the polarization estimation of scattering waves in the underdetermined case, that is, the number of scattering waves from ships is larger than the number of sensors, this article proposes two estimation methods with different measurement models: 1) for the single-vector sensor model, this article proposes the polarization-invariant estimation signal parameters of via rotational invariance technique (ESPRIT)-based method. This method can estimate the polarization of signals containing target echo, interference, and noise, which can cure the problem that the accuracy of the existing method is poor under low interference signal ratio (ISR) and 2) for the multivector sensor model, this article proposes an improved ESPRIT method based on the spatial-invariant and time-invariant simultaneously, which can increase the degree of freedom (DOF) without increasing hardware cost. As for another problem of multivector sensor, that is, almost all existing methods assume that the number of scattering waves is known, this article introduces the polarization spectrum for the first time, which can estimate the polarization parameters when the number of scattering waves is unknown. Finally, we analyze the two proposed ESPRIT-based methods compared with some existing methods through Monte Carlo simulation, and the results demonstrate the efficiency of the proposed methods.