应用于卫星导航功率倒置阵的改进LMS算法*

采用功率倒置准则的自适应天线阵特别适合于弱信号、强干扰的场合,因而在卫星导航系统中得到了广泛的应用。针对基于最小均方误差(LMS)算法实现的卫星导航功率倒置阵在干扰数目或干扰功率突然减少时,算法收敛慢、影响信号接收性能的问题,分析了这一现象的产生机理,并提出了相应的改进算法。改进算法通过功率监测来检测干扰数目或干扰功率的突变,然后对LMS算法进行复位处理重置权值来达到迅速收敛的目的。仿真结果表明,与原算法相比,改进算法可显著提高功率倒置阵的收敛速度。

An improved LMS algorithm for power-inversion GNSS antenna array

The power-inversion (PI) adaptive array is very suitable for situations where the desired signals are very weak while the interfering signals are much stronger, thus, it is widely used in Global Navigation Satellite System (GNSS). For LMS-based PI adaptive array used in GNSS receivers, the convergence rate is very slow when sudden change in interference number or interference power occurs. This will degrade the performance of receiving the satellite signals. The cause of this phenomenon is analyzed. Then, we proposed an improved LMS algorithm to solve this problem. The key novelty of the proposed method is that it monitors the power of the reference antenna output to detect any sudden change in interference number or interference power. Once the interference number or interference power decreases suddenly, the weight vector will be initialized again to improve the rate of convergence. Simulation results show that the improved method outperforms the original algorithm in rate of convergence.