卫星接收机干扰抑制关键技术研究与实现

【作者】 刘田；

【导师】 唐友喜；

【作者基本信息】 电子科技大学 ， 通信与信息系统， 2007， 硕士

【摘要】 空间无线电通信(Space Telecommunications)作为我国当代无线通信的支柱产业之一,成为了现代社会中不可缺少的通信手段。其中,卫星导航系统(例如GPS、Galileo、GLONASS等)和卫星移动通信系统是业界研究的两项热点。现代卫星导航系统不仅为武器平台、部队乃至单兵提供高精度的时间信息和导航定位服务,同时其民用市场也急剧增大,在海洋救援、车辆导航等领域发挥着重要作用。而卫星移动通信系统是作为地面陆地通信的补充,是实现通信全球化、个人化、宽带化的重要组成部分。上述卫星系统虽然工作于不同的目的,却都面临着各种类型的干扰问题。对卫星导航来说,在干扰环境下,接收机会出现严重的定位误差,影响定位精度,影响制导武器的命中率;对卫星移动通信来说,干扰环境会提高系统的中断概率,恶化误码率性能。因此,研究干扰环境下的卫星接收机设计具有重要意义。本文以两类典型的卫星通信系统作为研究对象,拟在其接收机抗干扰设计方面做一些工作。这两种系统分别是GPS导航系统和采用OFDM调制技术的低轨移动卫星通信系统。在GPS导航系统中,针对抗干扰问题的解决,目前虽然存在大量的理论研究,但涉及具体工程实现的资料和文献还比较少。本文研究了若干适合GPS系统的接收机抗干扰技术,从工程实现的角度,提出了合适的干扰抑制方法,介绍了GPS抗干扰接收机原理样机的研制工作,详细描述了FPGA部分的实现。在低轨移动通信卫星系统中,通常意义下的抗干扰可以采用大量现有技术。因此,本文考虑基于正交频分复用(OFDM)的低轨移动卫星通信系统,研究了一种叠加部分功率训练序列的传输方式。该传输方式提高了空中接口的灵活性与数据传输效率,但人为引入了训练序列对数据的干扰。针对这种“人为干扰”的抑制,本文提出了一种用户数据和部分功率训练序列优化分离方法。该技术在采用OFDM的无线通信中,尤其是在分组传输中,有着广泛的应用前景。本文在卫星接收机抗干扰设计方面的研究成果,可应用于卫星导航接收机设计以及基于OFDM的卫星移动通信系统等无线通信系统的信号处理技术中,具有重要的理论及经济价值。更多还原

【Abstract】 Serving as a supporting industry for our country’s Wireless Communication project, Space Telecommunications have become an indispensably part of our modern society, within which satellite navigation system and satellite mobile communication system have become two hotspots of research works. Mordern satellite navigation system not only provides high precise time information and navigation service for military use, but also have a growing market for civil stuffs, such as ocean succor and car navigation. On the other hand, satellite mobile communication system acts as a supplement for Future Public Land Mobile Telecommunication System, and also an important part for realizing globalization, personalization and wideband communication systems.Although working for different purpose, all satellite systems face kinds of jammings. Jamming and interference may result in serious positioning error in satellite navigation system, and also increase outrage probability, deteriorate bit error rate performance in satellite mobile communication system. So it is important to study how to receive satellite signals under jamming environments.Although there are plenty of researches on anti jamming for GPS, Few are dealing with practical realization. In this paper, a number of anti-jamming technologies are studied for GPS navigation receivers. From a prototype designer’s point of view, a system suitable for both broadband and narrowband interference suppression is proposed through systematic analysis, in which the FPGA design’s results are given in detail.In LEO communication systems based on Orthogonal Frequency-Division Multiplexing (OFDM), when using the partial power training sequence to synchronize, the received data signals will be seriously interfered by the training sequence. This paper proposes an optimum method to suppress the interference from the training sequence to the data bearing OFDM symbols in frequency selective fading channels. A closed form formula for the optimized training sequence canceling factor is given by the theoretical analysis and its reasonability is verified by the simulation results.The research results of the satellite signal receiver’s anti-jamming techniques in this paper can be applied in the signal processing techniques of the modern satellite navigation and communication systems, which are of great theoretical importance and economic value.更多还原