Characterization of Inter-System Biases in GPS + BDS Precise Point Positioning

Cheng Ke,Shengli Wang,Yanning Zheng

doi:10.3390/app10144968

Cheng Ke, Shengli Wang + Show 1 more

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https://doi.org/10.3390/app10144968

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Abstract

With the combination of multi-GNSS data, the precise-point positioning (PPP) technique can improve its accuracy, availability and reliability: Inter-system bias (ISB) is the non-negligible parameter in multi-GNSS PPP. To further enhance the performance of multi-GNSS PPP, it is crucial to analyze the characterization of inter system biases (ISBs) and model them properly. In this contribution, we comprehensively investigate the characterization of ISBs between global positioning system (GPS) and BeiDou navigation satellite system (BDS) in different situations. (1) We estimate ISB by using different precise products from the Center for Orbit Determination (CODE), Deutsches GeoForschungsZentrum (GFZ) and Wuhan University (WHU). The results indicate that the one-day estimates of ISB are stable when using CODE and WHU products, whereas the estimates based on GFZ products vary remarkably. As for the three-day time series of ISB, a sudden jump exists between two adjacent days, which is due to the change of satellite clock datum; (2) We investigate the ISB characterization affected by the ambient environments of the receivers. The result shows that the ISBs estimated from receivers (and antennas) with same type are still inconsistent, which indicates that the ambient environment, probably the temperature, influences the ISB characterization as well, since the receivers are in different areas; (3) We analyze the ISB characterization affected by receiver and antenna type with the same ambient environment. To ensure the same ambient environment, the ultra-short baselines were applied to investigate the ISB characterization affected by the receiver and antenna type. With the insights into ISB characterizations, we carry out combined GPS and BDS PPP with modeling the ISB as time constant, random walk process and white noise. The results suggest that the random walk process outperforms in most cases, since it strengthens the model to some extend and, at the same time, considers the variation of ISBs.

Highlights

With the rapid developments and modernizations of the global navigation satellite systems (GNSSs) including the American global positioning system (GPS), Chinese BeiDou navigation satellite system (BDS), European Galileo and Russian GLONASS, the integration of multi-GNSS brings a better and wider range of positioning, navigation, timing (PNT)and atmospheric retrieval applications [1,2,3,4,5,6]
As for the three-day time series of Inter-system bias (ISB), a sudden jump exists between two adjacent days, which is due to the change of satellite clock datum; (2) We investigate the ISB
ISBs estimated from receivers with same type are still inconsistent, which indicates that the ambient environment, probably the temperature, influences the ISB characterization as well, since the receivers are in different areas; (3) We analyze the ISB characterization affected by receiver and antenna type with the same ambient environment

Summary

Introduction

With the rapid developments and modernizations of the global navigation satellite systems (GNSSs) including the American GPS, Chinese BDS, European Galileo and Russian GLONASS, the integration of multi-GNSS brings a better and wider range of positioning, navigation, timing (PNT). Atmospheric retrieval applications [1,2,3,4,5,6]. As compared to GPS-only case, the multiple constellation increases the satellites in common view, enabling a higher accuracy and more reliability in precise-point positioning (PPP). The higher redundancy of the multi-GNSS model shortens the initialization time of PPP. The combination of multi-GNSS opens up a new stage of its applications, whereas processing multi-GNSS data are more challenging [7,8].

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