Estimation algorithm of Doppler shift and time delay in HF channel sounding

Abstract

Doppler shift and propagation time delay are important parameters that require measuring in HF channel sounding. For the purpose of exact measurement of Doppler shift and time delay of HF channel, a parameter estimation algorithm is proposed on the basis of digital pulse compression technique, which achieves precise estimation of Doppler shift and channel time delay by means of performing time domain pulse compression of the received signal. The simulation results show that the algorithm proposed can estimate the Doppler shift and the time delay of BPSK signal precisely when the signal to noise ratio (SNR) is relatively high, no matter the Doppler spread is zero or 0.1Hz. Further more, the maximal estimation error of Doppler shift is 0.01Hz and the maximal estimation error of time delay is below two times of the sampling interval when the Doppler spread is zero, even though the SNR is down to −30dB. When the Doppler spread is 0.1Hz and the SNR is −20dB or above, the maximal estimation error of Doppler shift is 0.13Hz and the maximal estimation error of time delay is below two times of the sampling interval. And these show that the Doppler shift and time delay estimation algorithm based on digital pulse compression technique possesses a quite good performance even when the SNR is very low.