Space-time antijamming problems cause widespread concern recently in global navigation satellite system. Space-time adaptive procession (STAP) is an effective method to suppress interference signals, which contains two adaptive filters, i.e., spatial filter and temporal filter, and the array pattern can be automatically optimized by adjusting the weights obtained from a prescribed objective function. However, mismatch may occur between adaptive weights and data, due to the change of the interference location when receiver is shaking. In this case, the performance of STAP will degrade dramatically. To solve this problem, an effective nulling widen method based on uniform circular array (named as UCA-NW algorithm) is proposed for space-time antijamming. Through this method, an extension matrix is given to modify the covariance matrix and the formed null can be broadened from azimuth angle and pitch angle, respectively. Thus, this algorithm can suppress interference signals effectively when the receiver is shaking, and the width of nulls can be controlled easily. Simulation results are presented to verify the feasibility and effectiveness of the proposed algorithm.
2. Lu, D., R. B. Wu, and Z. G. Sue, "A space-frequency anti-jamming algorithm for GPS," Antennas and Propagation Society International Symposium, 2007.
3. Liu, F. L., G. Z. Sun, J. K. Wang, and R. Y. Du, "Null broadening and sidelobe control algorithm via multi-parametric quadratic programming for robust adaptive beamforming," ACES Journal, Vol. 29, No. 4, 307-315, 2014.
4. Ge, L., D. Lu, W. Wang, and L. Wang, "A high-dynamic null-widen GNSS anti-jamming algorithm based on reduced-dimension space-time adaptive processing," China Satellite Navigation Conference, 2015.
5. Mailloux, R. J., "Covariance matrix augmentation to produce adaptive array pattern troughs," Electronics Letters, Vol. 31, No. 10, 771-772, 1995.
6. Zatman, M., "Production of adaptive array troughs by dispersion synthesis," Electronics Letters, Vol. 31, No. 25, 2141-2142, 1995.
7. Guerci, J. R., "Theory and application of covariance matrix tapers for robust adaptive beamforming," IEEE Transactions on Signal Processing, Vol. 47, No. 4, 977-985, 1999.
8. Li, W. X., Z. Yu, Y. B. Ye, and B. Yang, "Adaptive antenna null broadening beamforming against array calibration error based on adaptive variable diagonal loading," International Journal of Antennas Propagation, Vol. 2017, No. 12, 1-9, 2017.
9. Jafargholi, A., M. Mousavi, and M. Emadi, "Wide-band VHF nulling by five elements spiral array antenna," ITS Telecommunications Proceedings, 2006.
10. Yang, H. W. and J. G. Huang, "A broadband constant beam width adaptive beamforming method," Computer Simulation, Vol. 10, No. 27, 339-342, 2010.
11. Liu, F. L., R. Y. Du, J. K. Wang, and B. Wang, "A robust adaptive control method for widening interference nulls," IET International Radar Conference, 2009.
12. Li, W. X. and B. Yang, "An improved null broadening beamforming method based on covariance matrix reconstruction," Applied Computational Electromagnetics Society Symposium, 2017.
13. Qian, J. H., Z. S. He, and Y. L. Zhang, "Null broadening adaptive beamforming based on semidefinite programming," Signal Processing, 2017.
14. Zhang, B. H., H. G. Ma, and X. L. Sun, "Robust anti-jamming method for high dynamic global positioning system receiver," IET Signal Processing, Vol. 10, No. 4, 342-350, 2016.
15. Zetterberg, P. and B. Ottersten, "The spectrum efficiency of a basestation antenna array system for spatially selective transmission," IEEE Transactions on Vehicular Technology, Vol. 44, No. 3, 651-660, 1995.
16. Riba, J., J. Goldberg, and G. Vazquez, "Robust beamforming for interference rejection in mobile communications," IEEE Transactions on Signal Processing, Vol. 45, No. 1, 271-275, 1997.
17. Ma, Y. X., L. Dan, W. Y. Wang, L. Wang, and R. B. Wu, "A high-dynamic null-widen GPS anti-jamming algorithm based on statistical model of changing interference DOA," China Stellite Navigation Conference, 2014.