基于不同ISB估计模型的多GNSS组合实时精密单点定位性能分析

Performance Analysis of Multi-GNSS Combined Real-Time Precise Point Positioning with Different ISB Estimation Models

多GNSS(global navigation satellite system)组合精密单点定位(precise point positioning,PPP)中需要考虑系统间偏差(inter-system bias,ISB)的影响,定位时通常可采用时间常数、随机游走和白噪声模型对ISB参数进行估计。利用8个MGEX站观测数据和实时精密轨道钟差产品,基于3种ISB模型进行GPS+Galileo、GPS+BDS、GPS+Galileo+BDS组合的静态和仿动态实时PPP实验,研究不同ISB模型下的多GNSS组合实时PPP性能。结果表明,多系统组合静态定位模式下,ISB随机游走和白噪声估计模型的实时PPP收敛时间和定位精度相近,优于时间常数模型;动态模式下,ISB白噪声模型的实时PPP性能表现最优,随机游走次之,而ISB常数模型的PPP结果较差。因此,在多GNSS组合实时PPP时应采用白噪声模型进行ISB参数估计。

In multi-GNSS combined precise point positioning(PPP),the influence of inter-system bias(ISB)needs to be considered.Three stochastic models usually used to estimate ISB are time constant,random walk and white noise during positioning.This article uses the observation data of 8 MGEX stations and real-time precision orbital clock products to conduct the static and imitation dynamic PPP experiments of GPS+Galileo,GPS+BDS,GPS+Galileo+BDS multi-system combined based on three ISB models and studies the positioning performance of multi-GNSS real-time PPP under different ISB models.The results show that in the multisystem static positioning,the real-time PPP convergence time and positioning accuracy of the ISB random walk and white noise estimation models are similar,better than the time constant model;in the dynamic mode,the ISB white noise model has the best real-time PPP performance,followed by random walk,and the PPP result of the ISB constant model is the worst.Therefore,this article suggests that the white noise model should be used for ISB parameter estimation in multi-GNSS real-time PPP.