Improved Blind Source Extraction for Time Delay Estimate in Passive Coherent Location System

Abstract

Abstract-Target localization is one challenge in passive coherent location (PCL) radar system, and the time delay is the most important parameter in the location. The difficulty of time delay estimate (TDE) in PCL system is that the target signal is completely buried in direct path signal, multipath and clutter (DMC). The conventional clutter cancellation algorithms in matched filter (MF) are time consuming. In this paper, we propose a time delay estimate method based on blind source extraction (BSE) which directly extract the target signal from the mixed signals, thus a new passive coherent location system is built. In this model, the reference antenna is not needed any more. For low signal to interference plus noise ratio (SINR) and frequency overlapped signals in passive coherent location, we introduce the cyclostationarity to enhance the target signal. The experiments on FM broadcast signals show that the computational burden of the proposed algorithm is extremely small and the improved SNR satisfies the location requirements of PCL system.

Statistical Characteristics of the Multi-Path Time Delay and Doppler Shift of a Radar Wave Propagating Through the Ionosphere

“…For an adaptive system, the methods of multi-path cancelation and multi-path equalization were used by Ching and So to estimate time delay [8]. A new method for estimating the Doppler shift and time delay of the overlapping echoes was presented by Qi et al [9] and Zhang et al [10]. Other methods, such as the statistical moment method, have been used by some scholars to estimate the multi-path time delay and Doppler shift spread [11,12].…”