中文摘要：

由于卫星导航系统中导航卫星发射信道的记忆非线性效应，使带宽受限的二进制偏移载波（BOC）调制信号失真加剧，导航系统性能将受到严重影响。针对这个问题，建立并分析了导航发射信道模型，提出将等效简化信道模型的主体部分（HPA及其前后置滤波器）等效为Wiener—Hammerstein模型的思想，同时设计了一种针对此模型的基于直接学习结构的自适应LMS预失真方案。仿真结果表明，该方案能有效抑制BOC信号的带外频谱扩展，优化星座图，可以很好地消除导航信道对BOC信号的失真影响，在卫星导航系统中有着重要的意义和良好的应用前景。

英文摘要：

As the memory nonlinear effect of the navigation transmit channel in satellite navigation system, the distortion of the binary offset carrier （BOC） modulation signals, whose bandwidths are limited, will intensify, which will severely affect the performance of satellite navigation system. In order to solve the problem, the navigation transmit channel model is established and analysed in this paper. A novel idea which makes the main part of the equivalently-simplified channel model equivalent to Wiener-Hammerstein model is proposed. A scheme of adaptive LMS predistortion based on direct learning structure is designed. The simulation results show that this scheme can effectively inhibit the OOB spectrum spreading of BOC signal, optimize the constellation diagram and greatly eliminate the distortion effects of the navigation channel on BOC signal. It will have an impor- tant significance and a good prospect in satellite communication system.