Null-steering LMS Dual-Polarised Adaptive Antenna Arrays for GPS

W C Cheuk, M Trinkle, D A Gray

CRC for Sensor Signal and Information Processing, Dept of Electrical and Electronic Engineering, University of Adelaide, Adelaide SA.

DOI:                 

Abstract

The implementation of a null-steering antenna array using dual polarised patch antennas is considered. Several optimality criterion for adjusting the array weights are discussed. The most effective criteria minimises the output power of the array subject to maintaining a right hand circular polarisation (RHCP) response on the reference antenna. An unconstrained form of this criteria is derived, in which the reference channel is the RHCP output of the reference antenna and the LHCP output of the reference antenna is included as one of the auxiliary channels. An FPGA implementation of the LMS algorithm is then described. To prevent weight vector drift a variant of the circular leakage LMS algorithm was used. The implementation details of a simplified circular leakage algorithm more suited to an FPGA implementation are presented. This simplified leakage algorithm was shown to have a similar steady state weight vector as the full algorithm.

Keywords

GPS, Polarisation, Interference Mitigation, Adaptive filters.

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	Manz A.; Shallerg K.; Shloss P.; (2000): Improving WAAS Receiver Radio Frequency Interference Rejection. ION GPS 200, September 2000, pp471-479
[2]	Kunysz W. (2000): A Novel GPS Survey Antenna. ION NTM 2000, January 2000
[3]	Kunysz W. (2000): High Performance GPS Pinwheel Antenna. ION NTM 2000, September 2000
[4]	Dimos G.; Upadhyay T.; Jenkins T. (1995): Low-Cost Solution to Narrowband GPS Interference Problem Proc IEEE 1995 Naecon Meeting, vol I pp145-153 May 1995.
[5]	Trinkle M.; Gray D. (2001): GPS Interference Mitigation; Overview and Experimental Results. SatNav 2001, July, 2001.
[6]	Braasch M. S.; Rosen M. W. (1998): Low-Cost GPS Interference Mitigation Using Single Aperture Cancellation Techniques. Navigation 2000, 1998 ION National Technical Meeting.
[7]	Zoltowski M. D.; Gecan A. S. (1995): Advanced Adaptive Null Steering Concepts for GPS. MILCOM 95 Vol. 3, pp. 1214-1218.
[8]	Jian K.; Guosheng R.; Xizhang K. (1998): Power Inversion Adaptive Algorithm for GPS Receiver Antijamming. International Radar Symposium, September 1998. pp.1395-1401.
[9]	Fante R. L.; Vaccaro J. J. (2000): Wideband Cancellation of Interference in a GPS Receive Array. IEEE Transaction on Aerospace and Electronic Systems Vol. 36, No. 2 April 2000.
[10]	Trinkle M.; Cheuk W. (2003): Null-Steering GPS Dual-Polarized Antenna Arrays. SatNav July 2003.
[11]	Nagai E. C.; Blejer D. J.; Phuong T.; Herd J. (2002): Antijam Performance of Small GPS Polarimetric Array. IEEE Antennas and Propagation Society Int. Symp. 2002 Digest, Vol. 2, 16-21 June 2002, pp. 128-131.
[12]	Fante R. L.; Vaccaro J. J. (2002): Evaluation of Adaptive Space-Time-Polarization Cancellation of Broadband Interference. Proceedings of the 2002 IEEE Precision Location & Navigation Symposium pp.1-3.
[13]	Compton R. T. JR. (1981): On the Performance of a Polarization Sensitive Adaptive Array. IEEE Transaction on Antennas and Propagation, Vol. AP-29, No. 5, pp. 718-725, September 1981.
[14]	Legrand F.; Macaiau C.; Issler J. L.; Lestarquit L.; Mehlen C. (2000): Improvement of Pseudo Range Measurements Accuracy By Using Fast Adaptive Bandwidth Lock Loops. ION GPS 200, September 2000, pp. 2346-2356
[15]	Soloviev A.; van Grass F. (2004): Combining Low-Cost Inertial System with GPS Applications for General Aviation. GPS World, March 2004 pp. 38-45.
[16]	Horowitz L.; Senne D. (1981): Performance Advantage of Complex LMS for Controlling Narrow-Band Adaptive Arrays. IEEE Transactions on acoustics, and signal processing, Vol. ASSP-29, NO.3 June 1981.
[17]	Sethares W. A.; Dale A.; Lawrence C.; Johnson R. JR.; Bitmead R. R. (1986): Parameter Drift in LMS Adaptive Filters. IEEE Transactions on Acoustic, Speech and Signal Processing Vol. ASSP-34, No 4, August 1986.
[18]	Nascimento V. H.; Sayed A. H. (1999): Unbiased and Stable Leakage-Based Adaptive Filter. IEEE Transactions on Signal Processing, Vol. 47, No. 12 December 1999.
[19]	Ioannou P.; Tsakalis K. Robust discrete-time adaptive control in Narendra K. S, Ed.,(1986): Adaptive and Learning Systems: Theory and Applications. New York: Plenum, 1986, pp. 73-87.
[20]	Haykin S. (2002): Adaptive Filter Theory 4th Edition. Prentice Hall 2002.