2014 Volume 11 Issue 22 Pages 20140897
This paper proposes a method to estimate the time delay and delay rate when forecast data is inaccurate, in the Very Long Baseline Interferometry (VLBI) signal processing for the radio science receiver (RSR). Firstly, we find out rough time delay and rough Doppler shift through cross-correlation chart by using multiple-correlation method to enhance the SNR, which is suitable for the low SNR situation. Secondly, the data is compensated to get linear phase-frequency curve of the cross-power spectrum and calculate the precise time delay and delay rate by iteration. The method is tested with both simulation data and real received data. Result shows the signal detection limitation is at SNR = −23 dB. The standard deviation fit error for the curve can be under 0.05 rad. The method effectively increases the data processing probability.
