基于非差观测量的BDS+GPS近实时钟差估计

Quasi real-time clock estimation of BDS+GPS with no-difference observation

卫星钟差的难预测性是影响实时高精度定位的重要因素之一。为快速获得高精度位置或对流层等信息,在非差观测模型的基础上,本文提出了一种延迟量约1 h的近实时钟差估计策略,该策略主要包含超快速轨道解算和钟差估计两部分。经验证,预报部分第2~5 h的GPS轨道三维平均精度为3.85 cm,BDS GEO和IGSO+MEO轨道三维平均精度分别为81.4和21.74 cm。基于超快速轨道可获得近实时钟差精度GPS为0.054 ns,BDS为0.12 ns。最后通过BDS+GPS静态PPP试验验证了轨道和钟差的可用性。

The inscrutability of satellite clocks is one of the most important factors affecting real-time precise positioning. To obtain high accuracy position and zenith troposphere delay( ZTD) quickly,a strategy focusing on quasi real-time clock estimation delaying on hour is put forward. No-difference observation model is chosen during our procession. The proposed strategy consists of calculation of ultrarapid orbits and estimation of clocks. Experiments show that average 3 D RMS of 3 h prediction starting from 2 of GPS,BDS GEO and BDS IGSO+MEO are 3.85,81.4 and 21.74 cm respectively. Precision of quasi real-time estimation of GPS clock based on ultra-rapid orbits is 0.054 ns and that of BDS clock is 0.12 ns. Finally,static PPP experiment ensures the availability of orbits and clocks.