Simplified equivalent representation of GPS observation equations

The single and double-differencing operation of GPS observations is effectively used to eliminate nuisance parameters of receiver- and satellite-specific biases. According to the theorem of equivalent representation, we develop the simplified equations that equivalently represent the single and double-differenced observation equations using corresponding pseudo-observations in single or multi-baseline solutions. The transformation of the covariance matrix of original observables is no longer necessary. Therefore, the algorithms are very convenient for programming and efficient in computation. The unbiased estimate of the variance of unit weight is also derived from equivalent observation equations. The simplified equations are verified by numerical examples.     

利用EGM2008模型进行区域高程异常改正的实现

利用哈尔滨市区及周边17个水准点GNSS/水准数据,与EGM2008模型所计算的高程异常进行对比,对模型计算的高程异常进行改正,得到精度达到0.05 m的高程异常值。     

基于精选基准消秩亏的GNSS参考网数据处理方法

全球导航卫星系统（GNSS）参考网多用于估计卫星轨道/钟差、监测地表形变和速度场、确定精密地球自转参数等方面。相关数据处理模式包括：双差基线解（DD）和非差精密单点定位（PPP）等。本文首先从GNSS基本观测方程出发,通过选取两组基准参数,导出了上述两模式下的列满秩观测方程,然后分析了它们的不足,例如：相位偏差在DD模式中吸收了钟差,丧失了时不变特性;模糊度在PPP模式中吸收了相位偏差,失去了整数性。基于上述分析,本文提出了一种新的参考网数据处理方案,以充分融合DD和PPP模式的优势。它的关键策略是精选基准参数,以达到消秩亏的目的,具体优点体现在：相位偏差独立可估,若合理约束为时不变参数,可充分减少参数个数,提高网解精度;待估模糊度具备整周特性,经由模糊度固定,可改善网解可靠性。