通道失配和天线互耦对GPS抗干扰天线的影响

Effect of channel mismatch and mutual coupling on GPS adaptive array

通道失配和天线互耦对GPS(Global Positioning System)自适应抗干扰天线性能的影响,是细化GPS系统指标的基础,常被用来确定其技术实现方案.根据GPS的信号特点,利用加权矢量和干扰空间之间的正交性,分析了高频通道幅相偏差和幅相扰动I、/Q(In-phase/Quadrature)通道的幅位偏差以及天线互耦对ICR(Inter-ference Cancellation Ratio)和SINR(Signal Interference Noise Ratio)的影响.从理论上证明了ICR主要取决于高频通道的幅相扰动和I/Q通道的幅相偏差,而与高频通道的幅相偏差和天线互耦无关,修正偏差不一定能够提高SINR,修正互耦得到的SINR的改善仅正比于天线阵S矩阵(scattering matxix)的最大奇异值.仿真实验结果验证了上述结论.

In order to ascertain the specification of the main modules of an anti-jamming GPS receivers, it is necessary to analyze the effect of channel mismatch and antenna mutual coupling on SINR（signal interference noise ratio） and ICR（interference cancellation ratio）. In term of the signal environment of GPS, the expressions of SINR and ICR are conducted in existence of the deviation and the perturbation of the HF channel amplitude/phase （A/P）, I/Q imbalance and the antenna mutual coupling by using the orthogonality of weight vector and the jammer space. It is proved that ICR is mainly determined by the HF channel A/P perturbation and the I/Q imbalance, but almost independent of the HF channel A/P deviation and the mutual coupling, and the calibrations for the deviation aren＇ t always increase the SINR and the correction for mutual coupling can get the benefit of SINR just proportional to the maximal singular value of Scattering matrix. The simulation results on the aspect of the above are given.