基于Helmert方差分量估计的精密单点定位

Precise Point Positioning Based on Helmert Variance Component Estimation

精密单点定位一般将载波相位与伪距两类观测值作为观测量。一般情况下两类观测值的权比通常为固定常数，因此，常因伪距观测的低精度，降低精密单点定位精度。本文提出采用简化Helmert方差分量方法重新估计精密单点定位的载波相位与伪距观测值的观测精度，根据伪距与载波相位观测的实际不确定度，自适应地调整两类观测之间的权比，提高精密单点定位的精度。以IGS武汉站的观测数据为例，验证自适应调整两类观测权比的合理性。

Carrier- phase and pseudo -range are often used as the observation for precise point positioning （PPP） . The weight ratio of accuracy of carrier - phase and pseudo - range always is a constant. As a result, the ac- curacy of PPP is often degraded since the pseudo - range has a poor accuracy. In this paper, a simplified Helmert va- fiance component method is put forward to re - estimate the observation accuracy of cartier - phase and pseudo - range. The weight ratio is adaptively adjusted in accordance with the actual uncertainty of the two kinds of observa- tions to improve the accuracy of PPP. Data from Wuhan IGS set is used to verify it is rational to adaptively adjust the weight ratio of the two kinds of observation.