Detection of Bias in GPS satellites- Measurements for Enhanced Measurement Integrity

In this paper, the detection of a fault in the Global Positioning System (GPS) measurement is addressed. The class of faults considered is a bias in the GPS pseudorange measurements. This bias is modeled as an unknown constant. The fault could be the result of a receiver fault or signal fault such as multipath error. A bias bank is constructed based on set of possible fault hypotheses. Initially, there is equal probability of occurrence for any of the biases in the bank. Subsequently, as the measurements are processed, the probability of occurrence for each of the biases is sequentially updated. The fault with a probability approaching unity will be declared as the current fault in the GPS measurement. The residual formed from the GPS and Inertial Measurement Unit (IMU) measurements is used to update the probability of each fault. Results will be presented to show the performance of the presented algorithm.

• Mamoun F. Abdel-Hafez

• Estimation and filtering
• Statistical data analysis
• Faultdetection and identification.

[1] P. S. Maybeck, Stochastic Models, Estimation and Control, Volume 1,
Navtech Book and Software Store, Arlington, VA, 1994.
[2] B. Hofmann-Wellenhof, H. Lichtenegger, and J. Collins, GPS Theory and
Practice, 4th Ed., Springer-Verlag/Wien, New York, 1997.
[3] B. W. Parkinson and J. J. Spiker, Global Positioning System: Theory
and Applications, Vol. 1 and 2, American Institute of Aeronautics and
Astronautics, Inc., Washington D.C., 1996.
[4] J. A. Farrel and M. Barth, The Global Positioning System and Inertial
Navigation, McGraw Hill, San Francisco, 1999.
[5] B. J. Odelson, M. R. Rajamani, and J. B. Rawlings, A new Autocovariance
Least-Squares Method for Estimating Noise Covariances, Automatica, no.
42, no. 3, pp. 303-308, 2005.
[6] B. J. Odelson, A. Lutz, and J. B. Rawlings, The Autocovariance Least-
Squares Method for Estimating Covariances: Applications to Model-
Based Control of Chemical Reactors, IEEE Transactions on Control
Systems Technology, Vol. 14, No. 3, pp. 532-540, 2006.
[7] N. A. White, P. S. Maybeck, and S. L. DeVilbiss, Detection of Interference/
Jamming and Spoofing in a DGPS-Aided Inertial System, IEEE
Transactions on Aerospace and Electronic Systems, Vol. 34, No. 4, pp.
1208-1217, 1998.
[8] M. Wei and K. P. Schwarz, A strapdown inertial algorithm using an
Earth-fixed Cartesian frame, Navigation, Journal of the Institute of
Navigation, Vol. 37, No. 2, pp. 153-167, 1990.
[9] S. Hong, M. Lee, J. Rios, and J. L. Speyer, Observability Analysis of
GPS Aided INS, Proceedings of the 2000 Institute of Navigation, Salt
Lake City, UT, Sept. 2000.
[10] W.R. Williamson, M.F. Abdel-Hafez, I. Ree, E. Song, J. Wolfe, D.
Cooper, and J. L. Speyer, An Instrumentation System Applied to Formation
Flight, IEEE Transactions on Control Systems Technology, vol. 15, No.
1, pp. 75-85, 2007.
[11] I. Rhee, M.F. Abdel-Hafez, and J.L. Speyer, On the Observability
of Strapdown INS System During Maneuvers, IEEE Transactions on
Aerospace and Electronic Systems, Vol. 40, No. 2, pp. 526-536, 2004.