导航信号预失真算法设计及评估-通信与信息系统专业论文.docxVIP

华中科技 大学硕士 学 华 中 科 技 大 学 硕 士 学 位 论 文 II万方数据 II 万方数据 Abstract GNSS provides passive positioning service by transmitting radio signal with the on-orbit satellites which makes signal quality play a crucial role for the system performance. Practical transmitted navigation signal is the product of ideal signal which experienced a series of linear and non-linear distortions due to the non-idealities of core devices in the on-board payload, modernized navigation signal is affected by such non-idealities more significantly because of its wider bandwidth compared with traditional GPS signal. The distorted navigation signal may lead to the degradation of positioning precision and accuracy or even disable the system from positioning, therefore compensation for the distortion properties of signal transmitting channel is of great significance. For the purpose of improving the deterioration effect on signal quality introduced by the non-idealities of on-board transmitting channel, this thesis studies the channel compensation algorithm by means of signal predistortion and evaluates its improvement for signal quality. In this paper: generalized navigation signal model is studied as well as the receiving theory, influence of signal distortion over receiving performance is analyzed; quality evaluation indices used for navigation signal are introduced, relation between above evaluation indices and receiving performance is analyzed; core devices of the on-board payload are modeled respectively including memoryless high power amplifier, high power amplifier with memory, filter, their influence on navigation signal quality is analyzed; predistortion algorithm based on lookup table is proposed for memoryless high power amplifier, where on-line learning and off-line learning schemes are included and their linearization performance is verified; predistortion algorithm for high power amplifier with memory is proposed including an indirect-learning-based memory polynomial method and a filter l