- Volume 7 Issue 3
In this study, a real-time architecture for the detection of clock jumps in the GPS clock behavior is proposed. GPS satellite atomic clocks have characteristics of a second order polynomial in the long term showing sudden jumps occasionally. As satellite clock anomalies influence on GPS measurements which could deliver wrong position information to users as a result, it is required to develop a real time technique for the detection of the clock anomalies especially on the real-time GPS applications such as aviation. The proposed strategy is based on Teager Energy operator, which can be immediately detect any changes in the satellite clock bias estimated from GPS carrier phase measurements. The verification results under numerous cases in the presence of clock jumps are demonstrated.
GPS;Satellite clock anomaly;Clock jump detection;Teager energy
- A. Hansen, T. Walter, P. Enge and D. Lawrence, "GPS satellite clock event SVN 27 and its impact on augmented navigation systems," in Proceedings of ION GPS-98, Nashville, Tennessee, September 1998.
- ICAO, ICAO Annex 10, International Standards and Recommended Practices, Aeronautical Telecommunications, vol. I, Radio Navigation Aids, 2001.
- P. Misra and Per Enge, Global Positing System: Signal, Measurement, and Performance, Ganga-Jamuna Press, 2001.
- RTCA, Minimum Aviation System Performance Standards for LAAS, RTCA DO-245, Washington DC, USA, 2004.
- RTCA, Minimum Operational Performance Standard for GPS/WAAS Airborne Equipment, RTCA DO-229c, Washington DC, USA, 2001.
- J. Phelan, T. Dass, G. Freed, J. Rajan, J. D'Agostino and M. Epstein, "GPS block IIR clocks in space: current performance and plans for the future," in Proceeding of 37th PTTI Meeting, Vancouver, Canada, August 2005.
- S. Czopek, "Frequency and phase break detection," in Proceeding of 41st PTTI Meeting, New Mexico, USA, November 2009.
- Q. Wang and P. Rochat, "An anomaly clock detection algorithm for a robust clock ensemble," in Proceeding of 41st PTTI Meeting, New Mexico, USA, November 2009.
- E. Nunzi, L. Galleani, P. Tavella and P. Carbone, "Detection of Anomalies in the Behavior of Atomic Clocks," IEEE Transactions on Instrumentation and Measurement, vol. 56, no. 2, pp.523-528, 2007. https://doi.org/10.1109/TIM.2007.891118
- W. Riley, "Algorithms for Frequency Jump Detection," Metrologia, vol. 45, pp.154-161, 2008. https://doi.org/10.1088/0026-1394/45/6/S21
- L. Galleani and P. Tavella, "Detection and identification of atomic clock anomalies," Metrologia, vol. 45, pp.127-133, 2008. https://doi.org/10.1088/0026-1394/45/1/C01
- J. Kaiser, "On a Simple Algorithm to Calculate the Energy of a Signal," in Proceeding of ICASSP, New Mexico, USA, April 1990.
- P. Maragos, "On Amplitude and Frequency Demodulation Using Energy Operators," IEEE Transactions on Signal Processing, vol. 41, no. 4, pp.1532-1550, 1993. https://doi.org/10.1109/78.212729
- R. Dunn, T. Quatieri and J. Kaiser, "Detection of Transient Signals Using the Energy Operator," in Proceeding of ICASSP, Minnesota, USA, April 1993.
- R. Hamila, M. Renfors, M. Gabbouj and J. Astola, "Time-frequency signal analysis using Teager energy," in Proceeding of 4th ICECS, Cairo, Egypt, December 1997.
- K. Senior, P. Koppang, D. Matsakis and J. Ray, "Developing an IGS Time Scale," IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, vol. 40, pp.585-593, 2003.
- IGS website, http://igscb.jpl.nasa.gov/
- B. Parkinson and J. Spilker, The Global Positioning System: Theory and Applications, AIAA, Washington, DC, 1996.
- J. Farrell and M. Marth, The Global Positioning System and Inertial Navigation, Mcgraw-Hill, 1999.