C波段增强型接收机关键技术研究

发布时间：2018-04-21 08:29

本文选题：C波段 + 弱信号捕获　；参考：《西安电子科技大学》2014年硕士论文

【摘要】：目前,以GPS为代表的卫星导航产品越来越多,并且从军用领域渗透到民用领域,甚至是高楼林立的城市、室内和隧道等复杂环境,因此导航信号会受到遮挡、多径、噪声和干扰等诸多因素的影响,幅度和相位发生剧烈变化,进而信噪比衰减严重。本文根据项目需求,需要对C波段上的数据进行准确的接收,而C波段上导航信号的空间链路损耗特别大,这也就使得接收到的导航信号非常微弱,因此,文章主要针对弱信号的高灵敏度增强接收进行分析和研究。作为接收机的重要组成部分,基带信号处理模块的好坏决定了接收机在导航数据接收过程中的性能好坏,因此对基带信号处理算法的改进是提高接收机灵敏度的关键。基于此,展开了以下研究：对导航信号的组成结构、接收机前端处理和基带信号处理的工作流程以及工作原理做了详细介绍,作为对导航信号的产生和接收过程背景知识的补充。针对弱信号的捕获展开介绍,以并行码相位捕获算法为基础来提高捕获的速度和精度；另外,相干积分、非相干积分和差分相干积分都是通过累加来提高信噪比的基础算法。捕获以并行码相位捕获算法为基础,通过对积分方式进行结合实现算法的优化：首先介绍了结合相干积分和非相干积分的捕获算法—组合相干捕获,该捕获方法提高信噪比的同时消除了相干积分对比特数据跳变的影响,但是非相干积分引入了平方损耗；相干积分和差分相干积分组合成差分相干捕获算法,保留优势的同时对平方损耗进行削弱,但是差分相干积分计算量太大；从精简计算量的角度进行优化,得到简易差分相干捕获算法。从捕获门限、检测概率和时间复杂度三个方面进行捕获性能分析,并通过实际仿真证实了改进算法的优越性。对于弱信号的跟踪过程,本文先具体介绍了跟踪环路中载波环和码环的工作原理和结构。接着对实际接收的导航数据进行接收,验证了跟踪算法的有效性。最后提出了一种相位补偿的算法,即采用左、右旋圆极化天线对线极化天线发射的导航信号同时进行接收,对CAPS系统中因为收发天线极化方式不同而造成极化损耗的现象进行补偿和修正,实现增强接收的效果。最后介绍了算法实现的硬件平台及软件平台,列出了算法实现的具体步骤,对本文提出的算法进行了实际验证。
[Abstract]:At present, there are more and more satellite navigation products represented by GPS, and they infiltrate into the civilian field from the military field, even in complex environments such as cities with high buildings, rooms and tunnels, so the navigation signals will be blocked and multipath. Many factors, such as noise and interference, cause dramatic changes in amplitude and phase, which leads to the serious attenuation of SNR. According to the requirements of the project, we need to receive the data on C-band accurately, and the spatial link loss of the navigation signal in C-band is very large, which makes the received navigation signal very weak. In this paper, the high sensitivity enhanced receiver of weak signal is analyzed and studied. As an important part of the receiver, the baseband signal processing module determines the performance of the receiver in the process of receiving navigation data, so the improvement of the baseband signal processing algorithm is the key to improve the sensitivity of the receiver. Based on this, the following research is carried out: the structure of navigation signal, the workflow and working principle of receiver front-end processing and baseband signal processing are introduced in detail. As a supplement to the background knowledge of the process of generating and receiving navigation signals. Based on the parallel code phase acquisition algorithm, the acquisition speed and accuracy are improved. In addition, coherent integral, incoherent integral and differential coherent integral are all basic algorithms to improve SNR by cumulation. Based on the parallel code phase acquisition algorithm, the algorithm is optimized by combining the integration method. Firstly, the combined coherent acquisition algorithm, which combines coherent integral and incoherent integral, is introduced. The acquisition method not only improves SNR but also eliminates the effect of coherent integral on bit data jump, but incoherent integral introduces square loss, and coherent integral and differential coherent integral are combined to form differential coherent acquisition algorithm. At the same time, the square loss is weakened while the advantage is preserved, but the difference coherence integral is too much to calculate, and the simple differential coherent acquisition algorithm is obtained by optimizing from the point of view of the simplified computation. The performance of the improved algorithm is analyzed from three aspects: the acquisition threshold, the detection probability and the time complexity, and the advantages of the improved algorithm are proved by practical simulation. For the tracking process of weak signals, the principle and structure of carrier loop and code loop in tracking loop are introduced in detail in this paper. Then the actual received navigation data are received to verify the effectiveness of the tracking algorithm. Finally, a phase compensation algorithm is proposed, in which the navigation signals transmitted by the line polarization antenna are received simultaneously by the left and right circular polarization antennas. This paper compensates and corrects the polarization loss caused by different polarization modes of receiving and transmitting antennas in CAPS system, and realizes the effect of enhancing the reception. Finally, the hardware platform and software platform of the algorithm implementation are introduced, the concrete steps of the algorithm implementation are listed, and the algorithm proposed in this paper is verified in practice.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN967.1

【相似文献】