Abstract: A method for estimating the frequency of signals based on the phase difference between long and short delay matches is proposed. This method uses the interferometer direction finder principle for reference, that is, small frequency offset estimation by measuring the interframe phase difference of the short delay is used to resolve the indistinct phase problem, and at the same time, estimation by long delay is used to improve precision. A great deal of simulation for various algorithms shows that the new algorithm not only has a good estimation accuracy, but also has a good frequency stability, which can be utilized for hardware implementation of the receiver system.

Key words: fast Fourier transform, differenced phase between multi-frames, interferometer direction finder, long and short delay matched