基于块平均预处理的GNSS-R延迟映射处理方法

为了提高导航卫星反射信号信噪比,提出了一种基于块平均预处理(BAP)的反射信号处理方法,该方法首先以伪码周期为块尺寸对接收信号进行分块,并对各分块进行叠加、平均,然后对平均后的信号进行相关处理.在此基础上,理论分析了块平均预处理对导航反射信号的影响,推导了镜面反射点反射信号处理增益的数学表达式,以及相关处理后得到的一维相关功率,对比分析了该方法与传统处理方法的计算复杂度,分析表明该方法对反射信号具有空域滤波效果,提高了镜面反射点反射信号的信噪比且有效降低了计算复杂度.最后,基于块平均预处理的软件接收机被开发,并对课题组实采的岸基GPS数据进行了处理,结果表明:与未块平均预处理的传统方法相比,在块平均预处理时间为2、5、10、15以及20ms时,该方法所得相关功率的峰值信噪比分别提高了约3.5、6.7、10.2、10.6和10.4dB,且在块平均预处理时间为10ms时,处理等长数据的时间缩短了近2.2倍. 

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 20ms, the method improves about 3.5, 6.7, 10.2, 10.6 and 10.4dB on signal-noise ratio of peak and reduces the processing time by about 2.2 times, with BAP being 10ms, compared with the traditional method.