Joint estimation of Doppler and time-difference-of-arrival exploiting cyclostationary property

For the problem of estimating the time-difference-of-arrival (TDOA) of radio waves impinging on one or a pair of antennas for the purpose of actively or passively locating the source of a communications or telemetry signal in the presence of interfering signals and noise, W A. Gardner has developed some effective methods, such as CCCC and SPECCOA etc. However, it is shown that CCCC, SPECCOA and related methods do not apply to moving targets because the Doppler shift changes the cycle frequencies of the signal of interest. Two new methods based on the cyclic cross-ambiguity (CCA) function and the spectrally cyclic cross-ambiguity (SCCA) function are introduced in the paper for the joint TDOA and Doppler estimation, and their consistency in estimating the TDOA and Doppler is also discussed. Practical experiments, utilising FM radio signals emitting from a remote FM transmitter to detect the planes and estimate the values of TDOA and Doppler, have been carried out. Experimental results demonstrate the efficiency of the CCA and SCCA methods in the estimation of TDOA and Doppler