A new method of the virtual TDOA estimation for the passive radar source localization based on PSAAA

The passive synthetic aperture antenna array (PSAAA) technology is inspired by the idea of synthetic aperture sonar and synthetic aperture radar, which is a new method used to the passive radar source localization using only one small aircraft. Virtual time difference of arrival (VTDOA) estimation is critical for the PSAAA technology, it is defined as the time difference of the radar pulse transmission from the radar source position to different virtual receivers, where the virtual receivers are the flight track position of the small aircraft at different flight time. In this paper, we present three different algorithms of curve fitting to approximate the main-beam pattern of the radar antenna, then the VTDOA can be estimated using the corresponding time of the peak of the curve. The simulation results show that the second-order polynomial of the least squares (LS) curve fitting algorithm is the optimal method to approximate the main beam pattern of the radar antenna at the receiver, which also is the optimal method to be used in the VTDOA estimation.

I. Introduction

With the rapid development of wireless communications and information technologies, passive emitter localization has been of considerable interest in several fields such as sensor networks [1]–[3], wireless communications [4]–[6], microphone arrays [7] [8], sonar [9] and electronic warfare (EW) [10] [11], etc. It is usually accomplished using a two-step approach for the passive localization task, i.e., the “association” and the “information-fusion”. In the “association” step, certain signal parameters, such as received signal strength index (RSSI), time difference of arrival (TDOA), angle of arrival (AOA) and frequency difference of arrival (FDOA) are extracted from the target source emissions. Then, in the “information-fusion” step, the target position is estimated by solving a set of nonlinear equations [12].