A real-time estimating algorithm of GLONASS inter-frequency code bias and its application in RTK

doi:10.11947/j.AGCS.2022.20200416

Abstract

Abstract: It is difficult to eliminate GLONASS inter frequency code bias (IFCB) by empirical model.In RTK positioning, especially for medium and long-distance heterogeneous baselines that need to take into account atmospheric delay, IFCB will reduce the convergence rate of ambiguity, and even cause incorrect ambiguity solutions.In this paper, a real-time estimation algorithm of inter-station IFCB is proposed. The new algorithm origins from the classical double differenced Hatch-Melbourne-Wübbena (HMW) combination and ionospheric free combination, can obtain precise IFCB after a short period of filtering. The experiment results show that IFCB between stations may up to several nanoseconds and are stable for a long time. As a ratio 3:5 of the prior error of GPS/GLONASS observations, the uncorrected IFCB may cause the performance of GPS/GLONASS RTK positioning worse than that of single GPS. The proposed algorithm can effectively mitigate the negative influence of IFCB, including the accuracy of ambiguity floating solutions, the convergence speed and fixed rates of RTK positioning results. For some baselines, the time to first fixed of RTK positioning accelerate from 9.2 s to 2.1 s, and the fixed solution ratios enhance from 84.5% to 97.9%.

Key words: GLONASS, IFCB real time correction, GPS/GLONASS combined RTK

CLC Number:

P228

XU Longwei, WU Zhongwang, DONG Xurong. A real-time estimating algorithm of GLONASS inter-frequency code bias and its application in RTK[J]. Acta Geodaetica et Cartographica Sinica, 2022, 51(2): 169-181.

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