GNSS-R delay mapping processing method based on block averaging pre-processing

To improve signal-to-noise ratio of global navigation satellite system reflected signals, a method of processing navigation satellites reflected signal based on block averaging pre-processing (BAP) was presented, which divided the received signals into blocks with period of pseudocode and achieved the mean values of blocks by superposition and averaging, and then performed the correlation process for the mean values. On the basis, the model of reflected signal which processed by BAP was theoretically analyzed; the mathematical expression of processing gain of signal reflected by specular point and correlation power model were derived; computational complexity of this method was compared with one of traditional method. The conclusion is that this method conducts the spatial filtering for reflected signals, improves signal-to-noise ratio and effectively reduces computational complexity. At last, a software receiver was developed to process coastal raw GPS data collected. The results show that when the BAP time are 2, 5, 10, 15 and 20 ms, the method improves about 3.5, 6.7, 10.2, 10.6 and 10.4 dB on signal-noise ratio of peak and reduces the processing time by about 2.2 times, with BAP being 10 ms, compared with the traditional method.