抗干扰卫星导航接收机关键技术研究

发布时间：2018-08-24 17:18

【摘要】：卫星导航接收机作为卫星导航系统的重要组成部分,是推动导航系统市场化和产业化的关键。随着北斗二代全球化战略的实施和国际卫星导航领域竞争的日益激烈,我国卫星导航事业正面临着巨大挑战。在当前形势下,着眼北斗卫星导航系统的发展趋势和实际需求,研究适应现行扩频导航体制的接收机关键技术,设计具有低复杂度、高灵敏度、高动态和强抗干扰能力的卫星导航接收机,将会对北斗卫星导航系统升级和产品研发奠定良好基础,为加快北斗卫星导航系统产业化进程,促进其健康可持续发展发挥重要作用。本文针对导航卫星接收机关键技术进行深入研究,研究内容主要涉及干扰检测、伪码捕获和载波跟踪三个方面。本文的主要工作和创新性成果包括:1.针对强噪声背景下的扫频干扰参数估计问题,提出一种基于混合相干累加和部分匹配滤波快速傅里叶变换的扫频干扰参数二次估计算法。利用混合相干累加结构和流水线设计实现搜索区间压缩和资源复用,在估计性能接近克拉美罗界的前提下使算法的计算复杂度和资源消耗均大幅降低。2.针对高动态低信噪比环境下的相干直扩信号捕获问题,提出一种基于传统时域匹配平均周期图算法的参数优化方法,使算法在满足系统捕获要求的前提下达到最低的计算复杂度,并在此基础上利用频率近似和分段补偿的方法对算法进行改进,提出一种分段移位平均周期图算法。该算法利用数据段间的频率关系和FFT运算的旋转移位特性将各时间窗的起始频偏调整至零点附近,在不损失捕获性能的基础上实现估计精度的有效提高和计算复杂度的大幅降低。3.针对低信噪比环境下的非相干直扩信号捕获问题,提出一种区域并行块捕获算法。该算法通过估计调制数据偏移量的存在区间并舍弃可能含有数据跳变的非有效数据段,以较少的估计支路消除非相干数据位对捕获性能带来的影响,并将计算复杂度设定为目标函数,利用割平面法在系统约束条件下对算法的全部关键参数进行联合优化,使其能够在低信噪比环境下保持较低的计算复杂度和较高的估计精度。4.针对高动态环境下的数据调制载波跟踪问题,提出一种嵌套自适应卡尔曼滤波载波跟踪算法,该算法根据导航卫星和接收终端的相对运动规律将“当前”统计模型与卡尔曼滤波相结合,首先根据机动目标加速度的相关性将收发双方上一时刻相对加速度的一步预测作为修正瑞利分布的均值来确定当前时刻加速度的概率分布,再根据概率分布选择相应的嵌套自适应卡尔曼滤波参数对目标进行自适应跟踪。与扩展卡尔曼滤波算法相比,该算法在几乎不增加资源消耗的前提下大幅提高了高动态数据调制载波相位跟踪的鲁棒性和精度。
[Abstract]:As an important part of satellite navigation system, satellite navigation receiver is the key to promote the marketization and industrialization of navigation system. With the implementation of Beidou's second generation of globalization strategy and the increasingly fierce competition in the field of international satellite navigation, China's satellite navigation industry is facing enormous challenges. Under the current situation, focusing on the development trend and actual demand of Beidou satellite navigation system, the key technology of receiver adapted to the current spread spectrum navigation system is studied. The design has low complexity and high sensitivity. The satellite navigation receiver with high dynamic and strong anti-jamming capability will lay a good foundation for the upgrading of the Beidou satellite navigation system and the research and development of the products, thus speeding up the industrialization process of the Beidou satellite navigation system. Promoting its healthy and sustainable development plays an important role. In this paper, the key technologies of navigation satellite receiver are studied in depth, including interference detection, pseudo code acquisition and carrier tracking. The main work and innovative results of this paper include: 1. 1. Aiming at the parameter estimation of frequency sweep interference in strong noise background, a quadratic estimation algorithm for sweep interference parameters based on mixed coherent cumulation and partial matched filter fast Fourier transform is proposed. Search interval compression and resource reuse are realized by using hybrid coherent accumulation structure and pipeline design. The computational complexity and resource consumption of the algorithm are greatly reduced by 0.2 when the estimation performance is close to the Clemero bound. A parameter optimization method based on the traditional time-domain matching average period diagram algorithm is proposed for acquisition of coherent DSSS signals in high dynamic and low SNR environments. On the premise of satisfying the requirement of system acquisition, the algorithm achieves the lowest computational complexity. On this basis, the method of frequency approximation and piecewise compensation is used to improve the algorithm, and a piecewise shift average period graph algorithm is proposed. The algorithm adjusts the initial frequency offset of each time window to near zero by using the frequency relation between the data segments and the rotational shift characteristic of the FFT operation. On the basis of no loss of capture performance, the estimation accuracy is improved effectively and the computational complexity is greatly reduced. A region parallel block acquisition algorithm is proposed for acquisition of incoherent DSSS signals in low SNR environment. By estimating the existing range of modulation data offset and abandoning the non-effective data segment which may contain data jump, the algorithm eliminates the influence of incoherent data bit on the acquisition performance with less estimation branch. The computational complexity is set as the objective function, and all the key parameters of the algorithm are jointly optimized under system constraints by using the cut plane method, so that the algorithm can maintain lower computational complexity and higher estimation accuracy under low signal-to-noise ratio (SNR). Aiming at the problem of data modulation carrier tracking in high dynamic environment, a nested adaptive Kalman filter carrier tracking algorithm is proposed. According to the relative motion of navigation satellite and receiving terminal, the current statistical model is combined with Kalman filter. Based on the correlation of acceleration of maneuvering target, the probability distribution of acceleration at current moment is determined by using the prediction of relative acceleration at the last moment as the mean value of the modified Rayleigh distribution. Then the corresponding nested adaptive Kalman filter parameters are selected according to the probability distribution to track the target adaptively. Compared with the extended Kalman filtering algorithm, the proposed algorithm greatly improves the robustness and accuracy of high dynamic data modulation carrier phase tracking without increasing the resource consumption.
【学位授予单位】：北京理工大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：P228.4

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