Parameter Estimation for Multipath Error in GPS Dual Frequency Carrier Phase Measurements Using Unscented Kalman Filters

  • Lee, Eun-Sung (Satellite Navigation System Department the Korea Aerospace Research Institute) ;
  • Chun, Se-Bum (Department of Aerospace Engineering, Konkuk University) ;
  • Lee, Young-Jae (Department of Aerospace Engineering, Konkuk University) ;
  • Kang, Tea-Sam (Department of Aerospace Engineering, Konkuk University) ;
  • Jee, Gyu-In (Department of Electronic Engineering, Konkuk University) ;
  • Kim, Jeong-Rae (School of Aerospace and Mechanical Engineering, Hankuk Aviation University)
  • Published : 2007.08.31

Abstract

This paper describes a multipath estimation method for Global Positioning System (GPS) dual frequency carrier phase measurements. Multipath is a major error source in high precision GPS applications, i.e., carrier phase measurements for precise positioning and attitude determinations. In order to estimate and remove multipath at carrier phase measurements, an array GPS antenna system has been used. The known geometry between the antennas is used to estimate multipath parameters. Dual frequency carrier phase measurements increase the redundancy of measurements, so it can reduce the number of antennas. The unscented Kalman filter (UKF) is recently applied to many areas to overcome some of the limitations of the extended Kalman filter (EKF) such as weakness to severe nonlinearity. This paper uses the UKF for estimating multipath parameters. A series of simulations were performed with GPS antenna arrays located on a straight line with one reflector. The geometry information of the antenna array reduces the number of estimated multipath parameters from four to three. Both the EKF and the UKF are used as estimation algorithms and the results of the EKF and the UKF are compared. When the initial parameters are far from true parameters, the UKF shows better performance than the EKF.

Keywords

References

  1. P. Fenton, W. H. Falkenberg, T. Ford, K. Ng, and A. J. Van Dierendonck, 'Novatel's GPS receiver; The high performance OEM sensor of the future,' Proc. of ION GPS-91, pp. 49-58, September 1991
  2. B. Townsend and P. Fenton, 'A practical approach to the reduction of pseudorange multipath error in L1 GPS receiver,' Proc. of ION GPS-94, pp. 143-148, September 1994
  3. V. Nee, Multiple and Multi-Transmitter Interference in Spread-Spectrum Communication and Navigation Systems, Ph.D. dissertation, Delft University, 1995
  4. B. Hofmann-Wellenhof, H. Lichtenegger, and J. Collins, Global Positioning System: Theory and Practice, Springer-Verlag, 1997
  5. P. Axelrad, C. J. Comp, and P. F. Macdoran, 'SNR based multipath error correction for GPS differential phase,' IEEE Trans. on Aerospace and Electronic Systems, vol. 32, no. 2, pp. 650-660, April 1996 https://doi.org/10.1109/7.489508
  6. G. Lu, Development of a GPS Multi-Antenna System for Attitude Determination, Ph.D dissertation, University of Calgary, December 1994
  7. C. E. Cohen, Attitude Determination using GPS, Ph.D. dissertation, Stanford University, 1996
  8. G. Lachapelle, H. Sun, M. E. Canmon, and G. Lu, 'Precise aircraft-to-aircraft positioning using a multiple receiver configuration,' Canadian Aeronautics and Space Journal, vol. 40, no. 2, pp. 74-78, 1994
  9. J. K. Ray, M. E. Cannon, and P. Fenton, 'GPS code and carrier multipath mitigation using a multi-antenna system,' IEEE Trans. on Aerospace and Electronic Systems, vol. 37, no. 1, pp 183-195, January 2001 https://doi.org/10.1109/7.913677
  10. E. Lee, S. Chun, Y. J. Lee, T. S. Kang, G. I. Jee, and M. F. Abdel-Hafez, 'Performance improvement of Wald test for resolving GPS integer ambiguity using a baseline-length constraint,' International Journal of Control, Automation, and Systems, vol. 4, no. 3, pp. 333-343, June 2006
  11. E. Lee, S. Chun, Y. J. Lee, T. S. Kang, and G. I. Jee, 'Multipath mitigation of GPS carrier phase measurements using unscented Kalman filter,' Proc. of ION NTM 2005, pp. 455-461, January 2005
  12. S. J. Julier and J. K. Uhlmann, 'A new extension of the Kalman filter to nonlinear systems,' Proc. of the 11th Int. Symp. on Aerospace/Defence Sensing, Simulation and Controls, pp. 182-193, April 1997