A New GNSS Single-Epoch Ambiguity Resolution Method Based on Triple-Frequency Signals

Shengli Wang,Ying Xu,Jian Deng,Xiushan Lu,Ziyuan Song

doi:10.3390/ijgi6020046

Abstract

Fast and reliable ambiguity resolution (AR) has been a continuing challenge for real-time precise positioning based on dual-frequency Global Navigation Satellite Systems (GNSS) carrier phase observation. New GNSS systems (i.e., GPS modernization, BDS (BeiDou Navigation Satellite System), GLONASS (Global Navigation Satellite System), and Galileo) will provide multiple-frequency signals. The GNSS multiple-constellation and multiple-frequency signals are expected to bring great benefits to AR. A new GNSS single-epoch AR method for a short-range baseline based on triple-frequency signals is developed in this study. Different from most GNSS multiple-constellation AR methods, this technique takes advantage of the triple-frequency signals and robust estimation as much as possible. In this technique, the double difference (DD) AR of the triple-frequency observations is achieved in the first step. Second, the triple-frequency carrier phase observations with fixed ambiguities are used with the dual-frequency carrier phase observations to estimate their ambiguity. Finally, to realize reliable GNSS single-epoch AR, robust estimation is involved. The performance of the new technique is examined using 24 hours of GPS/GLONASS/BDS observation collected from a short-range baseline. The results show that single-epoch AR of the GNSS signals can be realized using this new technique. Moreover, the AR of BDS Geostationary Earth Orbit (GEO) satellites’ observations is easier than are those of the Medium Earth Orbit (MEO) and Inclined Geosynchronous Satellite Orbit (IGSO) satellites’ observations.

Highlights

Centimetre-level accuracy positioning can be achieved using the Global Navigation Satellite Systems (GNSS) carrier phase observation, which has been used in military and civilian fields [1,2,3]
Research shows that the GLONASS and BDS have the potential capability for real-time atmospheric parameter retrieval for time-critical meteorological applications as GPS does, and that the combination of multi-GNSS observations can improve the performance of a single-system solution in meteorological applications, with higher accuracy and robustness [18]
This paper focuses on fixing the ambiguity of GNSS carrier phase observation based on the triple-frequency signals in real time

Summary

Introduction

Centimetre-level accuracy positioning can be achieved using the Global Navigation Satellite Systems (GNSS) carrier phase observation, which has been used in military and civilian fields [1,2,3]. Research shows that the GLONASS and BDS have the potential capability for real-time atmospheric parameter retrieval for time-critical meteorological applications as GPS does, and that the combination of multi-GNSS observations can improve the performance of a single-system solution in meteorological applications, with higher accuracy and robustness [18]. Three/Multiple-Carrier AR (TCAR/MCAR) [16] and Cascading Integer Resolution (CIR) [19] are the typical three/multiple-carrier AR methods Both TCAR and CIR use the same geometry-free model to fix the ambiguities with a three- or four-step rounding procedure that is biased by the residual ionospheric delay. Geng and Bock [23] proposed a method where the incoming triple-frequency GPS signals are exploited to enable rapid convergences to ambiguity-fixed solutions in real-time precise point positioning (PPP). This paper focuses on fixing the ambiguity of GNSS carrier phase observation based on the triple-frequency signals in real time.

Mathematical Model

GNSS Single-Epoch Ambiguity Resolution

Ambiguity Resolution of BDS Trriippllee--FFrreeqquueennccyy SSiiggnnaallss

Findings

GNSS Single-Epoch Ambiguity Resolution Based on Robust Estimation

Conclusions