Title :
Wavelet based approach for joint time delay and Doppler stretch measurements
Author :
Niu, X.X. ; Ching, P.C. ; Chan, Y.T.
Author_Institution :
Dept. of Electron. Eng., Chinese Univ. of Hong Kong, Shatin, Hong Kong
fDate :
7/1/1999 12:00:00 AM
Abstract :
A new wavelet-based algorithm for joint time delay and Doppler stretch estimation in passive radar, sonar, and GPS applications is described. By taking the cross wavelet transform of the noisy outputs from two spatially separated sensors, the wideband cross ambiguity function (WBCAF) can be computed. This in turn provides a direct measurement of the time difference and Doppler stretch between the two signals. The Cramer-Rao lower bound (CRLB) is derived and the performance of the proposed algorithm is analyzed. It is found that the theoretical variances of the estimates are unbiased and approach the CRLB at high signal-to-noise ratio (SNR). In order to improve the accuracy of the estimation under noisy environment, a simple denoising method is introduced. Simulation results are given to corroborate the analysis
Keywords :
Doppler measurement; Global Positioning System; delay estimation; radar tracking; radio direction-finding; radio tracking; sonar tracking; target tracking; wavelet transforms; Cramer-Rao lower bound; Doppler stretch estimation; GPS; cross wavelet transform; denoising method; direct measurement; high signal-to-noise ratio; joint time delay estimation; linear FM signal; noisy outputs; passive radar; signal model; sonar; spatially separated sensors; target localisation; target tracking; time difference; wavelet based approach; wideband cross ambiguity function; Delay effects; Delay estimation; Global Positioning System; Passive radar; Performance analysis; Sonar applications; Sonar measurements; Time measurement; Wavelet transforms; Wideband;
Journal_Title :
Aerospace and Electronic Systems, IEEE Transactions on
