GLONASS pseudorange inter-channel biases and their effects on combined GPS/GLONASS precise point positioning
- 1.7k Downloads
Combined GPS/GLONASS precise point positioning (PPP) can obtain a more precise and reliable position than GPS PPP. However, because of frequency division multiple access, GLONASS carrier phase and pseudorange observations suffer from inter-channel biases (ICBs) which will influence the accuracy and convergence speed of combined GPS/GLONASS PPP. With clear understanding of the characteristics of carrier phase ICBs, we estimated undifferenced GLONASS pseudorange ICBs for 133 receivers from five manufacturers and analyzed their characteristics. In general, pseudorange ICBs corresponding to the same firmware have strong correlations. The ICB values of two receivers with the same firmware may be different because of different antenna types, and their differences are closely related to frequency. Pseudorange ICBs should be provided for each satellite to obtain more precise ICBs as the pseudorange ICBs may vary even on the same frequency. For the solutions of standard point positioning (SPP), after pseudorange ICB calibration, the mean root mean square (RMS) improvements of GLONASS SPP reach up to 57, 48, and 53 % for the East, North, and Up components, while combined GPS/GLONASS SPP reach up to 27, 17, and 23 %, respectively. The combined GPS/GLONASS PPP after pseudorange ICB calibration evidently improved the convergence speed, and the mean RMS of PPP improved by almost 50 % during the convergence period.
KeywordsGLONASS GPS Inter-channel bias Pseudorange PPP
We thank Dr. Jianghui Geng, at University of California San Diego, for his valuable suggestions on this study. This study was supported by the National High Technology Research and Development Program of China (863 Program) (Grant No.2012AA12A202), China Postdoctoral Science Foundation (Grant No.2012M511671) and also by the Fundamental Research Funds for the Central Universities (Grant No.2012618020202).
- Al-Shaery A, Zhang S, Rizos C (2012) An enhanced calibration method of GLONASS inter-channel bias for GNSS RTK. GPS Solut 2012(1):1–9Google Scholar
- Kozlov D, Tkachenko M (1998) Centimeter-level, real-time kinematic positioning with GPS + GLONASS C/A receivers. Navigation 45(2):137–147Google Scholar
- Kozlov D, Tkachenko M, Tochilin A (2000) Statistical characterization of hardware biases in GPS + GLONASS receivers. In: proceedings of ION GPS-2000. US Institution of Navigation, Salt Lake City, Utah, pp 817–826Google Scholar
- Leos Mervart, Georg Weber (2011) Real-time combination of GNSS orbit and clock correction streams using a Kalman filter approach. In: proceedings of ION GNSS-2011. Institute of Navigation, Portland OR, pp 707–711Google Scholar
- Rossbach U, Hein G (1996) Treatment of integer ambiguities in DGPS/DGLONASS double difference carrier phase solution. In: proceedings ION GPS-1996. Institute of Navigation, Kansas City, MO, pp 909–916Google Scholar
- Tsujii T, Harigae M, Inagaki T (2000) Flight tests of GPS/GLONASS precise positioning versus dual frequency KGPS profile. Earth Planet Space 52:825–829Google Scholar
- Wanninger L, Wallstab-Freitag S (2007) Combined processing of GPS,GLONASS, and SBAS code phase and carrier phase measurements. In: proceedings of ION GNSS-2007. Institution of Navigation, Fort Worth, Texas, pp 866–875Google Scholar
- Yamanda H, Takasu T, Kubo N, Yasuda A (2010) Evaluation and calibration of receiver inter-channel biases for RTK-GPS/GLONASS. In: proceedings of ION GNSS-2010. Institute of Navigation, Portland, Oregon, pp 1580–1587Google Scholar
- Zinoviev AE (2005) Using GLONASS in combined GNSS receivers: current status. In: proceedings of ION GNSS-2005. Institution of Navigation, Long Beach, California, pp 1046–1057Google Scholar