Implementation Aspects of Wigner-Hough Transform Based Detectors for LFMCW Signals

Abstract

Linear Frequency Modulated Continuous Waveform (LFMCW) waveforms are widely used in Low Probability of Intercept (LPI) radars. In this work, Wigner-Hough based transforms are used to detect such waveforms. They are investigated for three aims: Minimizing the effects of Wigner-Ville Distribution (WVD) cross-terms in the transforms, reducing the complexity of hardware implementation and producing the transform results faster. Modified Wigner- Hough Transform (MWHT) is analyzed for the first aim. Sample and hold type intermediate sampling and column-based thresholding techniques are examined for the second and third aims. A signal database (3000 signals with different SNR levels) is created and used to evaluate the performances of 8 alternative methods on probability of detection and probability of chirp rate estimation. The results are compared for -3dB down to -14dB SNR levels. Proposed method is found to be the best candidate to be implemented on Field Programmable Gate Arrays (FPGA) since it produces better performance with less computational density.