Such kind of signal-selectivity algorithms in solving the problem of estimating time difference of arrival(TDOA) of radio waves

such as CCC method

has been developed to some extent by W.A.Gardner.But unfortunately

the methods mentioned above are not suitable for the cases when the echo signal from moving targets has nonzero Doppler shift

since the cycle frequency of echo signal varies with time.To solve the problem of estimating the TDOA of the FM signal with nonzero Doppler shift

a more generalized approach

which is referred to as the extended CCC(ECCC) method

is introduced in this paper.By utilizing the detection method of cell averaging constant false alarm rate(CA-CFAR)

the estimates of TDOA and Doppler shift can thus be determined by the peak position over the two-dimensional space of TDOA and Doppler shift.In addition

it can be seen in this paper that the class of algorithms developed by W.A.Gardner is just a special case

corresponding to zero Doppler shifts.Computer simulations are also performed on the given method and simulation results have shown that the novel method works more efficiently in highly corruptive environment than the conventional correlation methods do.