Frequency estimation of satellite-based automatic identification system signals

摘要

In this paper, a method of frequency estimation is presented for solving the problem of larger Doppler frequency offset in satellite-based Automatic Identification System (AIS). It takes the advantage of the autocorrelation function of signals to calculate the initial value of frequency offset estimation. By deriving the initial value estimation range, a set of possible frequency offset can be got. It uses the maximum likelihood theory to determine the exact estimator from the set. Computer simulations shows that the proposed method has better estimation performance, and frequency offset estimation error will be restricted in 100 Hz when signal-to-noise ratio is 0 dB, which is demanded in the satellite-based AIS. Additionally, its estimation range can be expanded to ± 4 KHz on Additive White Gaussian Noise channels.