The invention provides a method and a device for double-star
time difference /
frequency difference combined positioning. By using the method, the calculation efficiency and the measurement accuracy of the
time difference and the
frequency difference can be improved. According to the scheme, the method comprises the following steps of: (1) carrying out
time difference-
frequency difference combined coarse estimate, calculating A(tau, f)=FFT[r(n; tau)], directly measuring the carrier frequency of a
composite signal FORMULA for the search of the time difference each time, labeling a
frequency spectrum amplitude value and a time difference value and finding out a maximum position, wherein tau is equal to tau1, tau2, FORMULA and tauM; (2) extracting and filtering the
composite signal FORMULA, then measuring the carrier frequency, and coarsely estimating the frequency difference; (3) accurately calculating the frequency difference in the adjacent domain FORMULA of an estimated value in the coarsely measured frequency difference and accurately estimating the frequency difference; (4) accurately calculating the time difference in the adjacent domain FORMULA of an estimated value in the coarsely measured time difference and accurately estimating the time difference; and (5) accurately estimating the time difference, estimating the
time resolution 1 / Ts of the time difference by using a relevant method and improving the time difference estimate accuracy by using interpolation, wherein Ts is the sampling interval of signals. In the invention, the time difference is calculated by using the signals with a high sampling rate, the frequency difference is calculated by using the signals with a low sampling rate, and the problems of the calculation efficiency and the measurement accuracy of the time difference and the frequency difference are solved by combining the
time domain processing with the
frequency domain processing.