GPS Anomaly Analysis and Pseudorange Accuracy Improvement by Anomalous Satellite Elimination



Yoo, Yun-Ja;Cho, Deuk-Jae;Park, Sang-Hyun

  • 투고 : 2010.07.01
  • 심사 : 2010.09.09
  • 발행 : 2010.09.30


GPS anomaly has increased according to the degradation of satellite performance, and many GPS users could be exposed to any kinds of error-included signals without any previous notice when unscheduled error occurred. RSIM (Reference Station Integrity Monitors) is a typical monitoring method to broadcast PRC (Pseudo Range Correction) for users. However, there were some cases that the receiver detected the anomalous satellite's signal even though it was unhealthy set, consequently it occurred a large range error. Then it is important to monitor the integrity of GPS signal and it is needed to devise the correction method of pseudorange by eliminating error-occurred PRN for notification to GPS users when it is monitored that the anomaly occurred. This paper proposes the basic concept of how to correct the pseudorange. The paper also shows the analysis results of PRN10 GPS anomaly occurred on day 39 in 2007 with corrected results by eliminating anomaly satellite (PRN10). The proposed correction method shows decreased pseudorange error range compared to the case when the anomaly satellite were used.


GPS anomaly;unscheduled error;pseudorange error;integrity monitoring


  1. AISM-IALA (Association Internationale de Signalisation Maritime - International Association of Marine Aids to Navigation and Lighthouse Authorities) (2004), "IALA Recommendation R-121 On the Performance and Monitoring of DGNSS Services in the Frequency Band 283.5-325 kHz Edition 1.1", Appendix 1.
  2. B. Hofmann-Wellenhof, H. Lichtenegger and J. Collins (2001), "Global Positioning System: Theory and Practice", Springer published.
  3. Cho, D., Park, S., Choi J. and Suh, S. (2007), "A Study on Integrity Monitoring Improvement of the DGPS Reference Stastion", Journal of Korean Navigation and Port Research, vol.31, no.6, pp.509-514.
  4. Enge, P., Phelts, E. and Mitelman, A. (1999), "Detecting Anomalous Signals from GPS Satellites", Draft Stanford University Report.
  5. GPS Advisories/NANUs, United States Coast Guard Avail at:, [Accessed 22 June 2010].
  6. Gao, G. X., Tang, H., Blanch, J. and Lee, J. (2009), "Methodology and Case Studies of Signal-in-Space Error Calculation: Top-down Meets Bottom-up", Proceedings of the Institute of Navigation, September 22-25, pp.2824-2831.
  7. Korea Hydrographic and Oceangraphic Administration (2005), "A Study on the Method of GPS Signal Monitoring, Fault Detection and Identification, and Broadcasting", Research and Development of Korea WADGPS, SIS analysis, and Time synchronization of NDGPS station (III), September.
  8. Phelts, R.E., Akos, D.M. and Enge, P. (2000), "Robust Signal Quality Monitoring and Detection of Evil Waveforms", Proceedings of the Institute of Navigation 2000, pp.1180-1190.