【作者】 俞晨晟；

【导师】 李式巨； 赵民建；

【作者基本信息】 浙江大学 ， 信息与通信工程， 2008， 硕士

【摘要】 GNSS卫星导航定位技术在测绘、通信、军事、航天、电力、遥感等领域得到了广泛的应用。随着GNSS卫星导航技术应用范围的不断扩大,应用水平的不断提高,对卫星导航技术也提出了更高的要求。在军事和航天相关应用领域,载体运动的高动态特性使接收到的卫星信号具有很大的多普勒频移,信号的捕获跟踪变得十分困难;另外除美国的GPS系统外,俄罗斯的GLONASS系统和中国的BD-2系统也发展很快,如何利用多模式可见星多的优点也成为当前研究热点。本文旨在研究高动态环境下GNSS接收机和多模解算技术。论文的主要工作包括以下几个方面:(1)针对高动态环境下,研究基于匹配滤波时域并行、基于FFT频域并行和基于FFT/IFFT时域并行相关算法,分析了各自存在的优缺点,给出了仿真和解决问题的方法,对比分析了它们各自的运算速度、运算量和运算效率。(2)针对高动态环境下,对PLL、FLL、DLL环路进行深入研究,重点讨论了环路滤波器的噪声性能和动态应力,提出了一种锁频锁相环路级联的环路设计方法,保证在一定噪声性能条件下,大大提高环路的动态性能。(3)针对不同模式卫星间测距码误差的不同,及初始权阵给的不准确,提出了一种基于验后估计的权阵修正的方法,能在一定程度上提高定位精度。(4)针对多模式条件下,推导了加权GDOP的计算,分析了卫星数目对加权GDOP的影响,并给出基于六阶行列式的GDOP选星算法和仿真。(5)针对多模式条件下,建立多模式RAIM监测模型,详细推导了故障检测中多模加权条件下最小二乘残差法和奇偶空间法,并验证了两者的等价性,分析了RAIM技术的可用性判断依据,同时给出了故障隔离的两种方法:子集比较法和奇偶法,最后仿真验证了应用加权最小二乘残差法和传统方法在故障检测率和故障隔离率上的性能,同时也给出子集检测法和奇偶法的性能仿真。(6)基于前文对高动态GNSS接收机的研究和分析结果,结合实验室前期在软件和硬件上的积累,提出并实现了一个基于FPGA+DSP的全数字GNSS接收机方案。更多还原

【Abstract】 The navigation and position technology based on Global Navigation Satellite System (GNSS) are widely used in mapping, telecommunication, military products, astronavigation, electric power, remote sensing and so on. With the expanded application range and developed application quality, we require more higher develops on the navigation and position technology. Such as in the military and astronautic application, the high dynamic vehicle makes the satellite signal have higher Doppler frequency shift, and the Dopller change rapidly, so the acquisition and precise tracking of satellite signal becomes difficult. Otherwise, with the development of GLONASS and BD-2 system, including GPS, how to take advantage of the more visible satellites becomes research focus now. The goal of this thesis is to do research on technology of high dynamic GNSS receiver and mult-mode calculation.The thesis includes:(1). We do a lot of work on the algorithm of parallel correlation in time domain based on match filter, parallel correlation in frequency domain based on FFT and parallel correlation in time domain based on FFT/IFFT in high dynamic environment, of which we analyze the advantage and disadvantage. We propose solution of the problem with computer simulation, and compare the efficiencies of the parallel correlation algorithms by implement complexity.(2). We do research on the frequency locked loop (FLL), phase locked loop (PLL), and delay locked loop (DLL). We analyze the noise and high order response of the tracking loops. We propose a scheme of tracking loop with FLL and PLL in serials and rotating. This scheme has high performances of high order response and its noise performance is good. (3). With the problems that PN code error of different mode satellites is different, and the initial weighed matrix is wrong, we propose a method which can modify the weighed matrix based on posterior estimation. The method can improve the positioning accuracy.(4). We deduce the computation of WGDOP (Weighted Geometry Dilution of Precision), and we analyze the relationship between WGDOP and number of satellites. We propose a new method of selecting satellites based on six order determinant with simulation.(5). We build mult-mode RAIM (Receiver Autonomous Integrity Monitor) model, and we deduce the calculation of the least squares residual method and the parity space method in fault detection with mult-mode satellites and weighted matrix. It is proved that the two methods are equal. We analyze the RAIM availability algorithm and propose two methods of fault isolation which is the subset comparison method and the parity space method. We analyze the performance of the least squares residual method with weighted matrix in fault detection rate and fault isolation rate, comparing the traditional method. We also have performance simulation of the subset comparison method and the parity space method.(6). Due to analysis and simulation above, we design and implement a high dynamic GNSS receiver based on FPGA and DSP.更多还原