基于双通道接收的干扰对消性能分析

为了探究在工程实现中卫星通信地球站使用干扰对消抵抗来自空中平台或周边干扰的可行性，对不同接收环境下的干扰对消性能进行了分析。首先，在假定2个通道中干扰差异被准确估计并补偿的情况下，推导出理论性能的近似计算公式；然后，采用最小均方(least mean square, LMS)自适应滤波器对2个通道干扰的差异进行补偿，完成干扰对消；最后，通过仿真实验对使用LMS自适应滤波器的干扰对消进行验证。结果表明：干扰对消的理论性能在卫星信号与干扰入射夹角大于15°时信噪比恶化可以接近0 dB,而夹角小于15°时信噪比恶化程度明显提高；除了入射夹角的影响外，采用LMS自适应滤波器的干扰对消性能还受算法参数、干扰大小等其他因素的影响，对于固定频点的干扰，在入射夹角大于4°且主通道干信比小于30 dB时，干扰对消后信噪比恶化小于0.6 dB,而且这一结果基本不受采样率的影响。所提出的理论性能近似计算公式可以为干扰对消算法的性能评价提供参考，采用LMS自适应滤波器的干扰对消在算法参数设置合理的情况下可以接近理论性能。

Performance analysis of interference cancellation based on dual-channel receiver

In order to study the feasibility of interference cancellation in satellite communication ground stations to resist interference from air platforms or surrounding areas in engineering applications, an analysis of interference cancellation performance was conducted under various reception environments. Firstly, assuming that the interference difference in two channels was accurately estimated and compensated, an approximate calculation formula of theoretical performance under this method was derived. Then the Least Mean Square (LMS) adaptive filter was used to compensate the interference difference to complete the interference cancellation. Finally, the interference cancellation using LMS adaptive filter was verified by simulation experiments. The results show that the decrease of signal to noise ratio can be close to 0 dB in the theoretical performance when the included angle between satellite signal and interference is greater than 15°, while the decrease of signal to noise ratio will be significantly improved when the angle is less than 15°. In addition to the influence of the included angle, the performance of interference cancellation using LMS adaptive filter is also affected by algorithm parameters, interference power and other factors. For fixed-frequency interference, when the included angle is greater than 4° and the signal to interference ratio of main channel is less than 30 dB, the signal to noise ratio decreases less than 06 dB after interference cancellation, and this result is essentially unaffected by the sampling rate. The proposed approximate calculation formula of theoretical performance can provide reference for the performance evaluation of interference cancellation algorithm. The interference cancellation using LMS adaptive filter can approach the theoretical performance when the algorithm parameters are appropriately configured.