地基GNSS接收伪距信号中的日重复项

Daily repetition variations in pesudorange signals from ground-based GNSS receivers

多路径误差每天重复出现,是存在于伪距信号中的日重复项。伪距中的多路径误差可通过滤波的方法提取,但在多路径误差信号和噪声信号频率未知或者重叠的情况下,不能将二者完全分开。本研究尝试提出一种新技术解决这个问题,将伪距中卫星与台站的距离、钟差、硬件延迟、电离层延迟、对流层干延迟项消除后,得到包含多路径误差、对流层湿延迟和观测噪声的残差数据,再通过主成分分析的方法提取多路径误差。通过主成分分析法得到重构的第一主成分每天都重复出现,其亦为伪距信号中的日重复项,理论上是多路径误差。然而,日重复项的数值大小是前人研究的4到5倍。这表明伪距信号中还包含了除多路径误差以外的其他日重复项。通过分析17个台站的结果,本研究发现上述的其他日重复项,在使用相同类型接收机主机的台站之间的相关性更高。这反映了该日重复项与接收机主机型号有关,可能是与接收机主机相关的系统误差。

Multipath error are daily repetition variations,which appear in pesudorange every day.A filtering algorithm is a typical and efficient strategy to extract the multipath errors from the pesudorange signal.However,the straightforward method gets struggling if the frequency of multipath errors and noises are unknown or mixed up.This study attempts to propose a new technology to figure out this problem.We extract the multipath error from residual data by applying the principal component analysis.It should be noted that residual data containing multipath errors,tropospheric wet delay and noises,are obtained by pesudorange eliminating the distance between a satellite and a station,clock errors,hardware delay,ionospheric delay and tropospheric hydrostatic delay.Reconstructed first principal components obtained by principal component analysis have periodic characteristics called daily repetition variations,and they are multipath error theoretically.However,its value is 4 to 5 times bigger than previous studies.It indicates that there are other daily repetition variations besides multipath errors in pesudorange signals.We analyzed the data from 17 stations,and results show that the correlations of this daily repetition variations are higher among stations using the same type of receiver host.It suggests that the daily repetition variations in the pseudorange signals are associated with the type of receiver host,and it probably is a system error related to the receiver host.