Fast algorithm for joint TDOA/FDOA estimation of Chirp signals

A novel algorithm based on the fractional Fourier transform for estimating time difference of arrival(TDOA) and frequency difference of arrival(FDOA) between chirp signals is proposed in this paper. The proposed approach first estimates the location of the ridge of the cross-ambiguity function, and makes the ridge pass through the origin by frequency compensating, and then accomplishes one-dimensional search for the peak along the ridge by just searching for the peak of the fractional correlation of the two signals, thus obtaining the estimation of TDOA and FDOA. Due to the use of one-dimensional search and FFT-based processing, the proposed process decreases the computation cost greatly. For multi-component Chirp signal, the proposed approach can also estimate the TDOA/FDOAs of different components according to different ridge positions. Simulation results show that the proposed algorithm can estimate the TDOA/FDOA of Chirp signals accurately and the root mean square error gets close to Cramer-Rao bound with the increase of signal noise ratio.