BeiDou satellite-induced code pseudorange variations: diagnosis and therapy

Lambert Wanninger,Susanne Beer

doi:10.1007/s10291-014-0423-3

Abstract

Code pseudorange measurements of the Chinese GNSS BeiDou reveal variations which result in code---phase divergences of more than 1 m. We have analyzed these delay variations based on observation data of the International GNSS Service and its Multi-GNSS Experiment campaign. Our results confirm that these code variations are elevation-dependent when observed by receiving antennas on the earth's surface. In addition, we found significant differences between two groups of satellites and among carrier frequencies. These delay variations have only little effects on absolute BeiDou positioning using broadcast ephemerides due to the limited accuracy of the obtainable positions. But, all precise applications which use code measurements are severely affected. These applications include, e.g., certain algorithms used in Precise Point Positioning (PPP), especially PPP ambiguity fixing and single-frequency PPP based on the ionosphere-free code---carrier combination. We developed a correction model and determined correction parameters in order to accommodate these symptoms. Application examples demonstrate the successful mitigation of these code pseudorange variations.

Highlights

The constellation of the Chinese GNSS BeiDou, abbreviated as BDS and formerly referred to as COMPASS, presently consists of 14 active satellites (CSNO 2013), four satellites in medium earth orbits (MEO), five satellites in inclined geostationary orbits (IGSO), and five satellites in geostationary orbits (GEO)
All precise applications which use code measurements are severely affected. These applications include, e.g., certain algorithms used in Precise Point Positioning (PPP), especially PPP ambiguity fixing and single-frequency PPP based on the ionospherefree code–carrier combination
BeiDou observation data sets from globally distributed stations equipped with multi-GNSS and multi-frequency geodetic-grade receivers and antennas are collected and made publicly available by the International GNSS Service (IGS, Dow et al 2009) through its MultiGNSS Experiment (MGEX, Montenbruck et al 2014)

Summary

Introduction

The constellation of the Chinese GNSS BeiDou, abbreviated as BDS and formerly referred to as COMPASS, presently consists of 14 active satellites (CSNO 2013), four satellites in medium earth orbits (MEO), five satellites in inclined geostationary orbits (IGSO), and five satellites in geostationary orbits (GEO). Our results confirm that these code variations are elevation-dependent when observed by receiving antennas on the earth’s surface. The elevation-dependent biases in BeiDou code measurements are detectable in MEO satellite passes since these passes usually extend over large elevation ranges.

Objectives

Results

Conclusion