【作者】 张大卫；

【导师】 胡修林；

【作者基本信息】 华中科技大学 ， 通信与信息系统， 2010， 博士

【摘要】 卫星导航定位系统涉及一个国家的政治、经济、军事等领域,对维护国家利益具有重大意义。卫星导航定位系统中直接面对用户的就是定位接收机,而同步技术关系到定位接收机的性能和全部功能的实现,因此对卫星定位接收机同步技术的研究具有重要意义。论文主要研究了卫星定位接收机的伪码同步、载波同步和信息同步。取得的主要研究成果如下:对于伪码同步。特别侧重于研究如何提高伪码同步与相位测量的精度。分析了影响伪码跟踪环同步精度的主要因素以及主动定位方式和被动定位方式对伪码同步算法的不同要求。在不提高采样率的前提下,从两个不同思路设计了伪码同步与相位测量算法。在等量采样条件下,通过对延迟锁相环的鉴相结果做最小二乘线性拟合,实现了伪码相位的精确估计,在此基础上设计的双路时差测量算法成功应用于BD-1定位接收机中,在信号功率为-152.6dBW的条件下,时差测量精度达到5ns;成功运用非等量采样理论,设计了非等量采样伪码同步与相位测量算法,实现了伪码相位的精确同步与测量,特别对该算法的核心——高精度码NCO的理论与设计进行了详细讨论,算法成功应用于BD-2定位接收机中,在码速率为10.23MHz,信号功率为-133dBm的条件下,伪码相位测量精度小于1ns(小于0.01chip)。对于载波同步。分析了主动定位方式与被动定位方式在接收机动态性能方面的不同要求,设计了两种载波跟踪算法。AFC自适应载波跟踪算法通过对同相正交环跟踪的结果进行处理获得残留频偏的大小和极性信息,再通过AFC电路调整本地VCO以减小残留频偏,环路参数与本地VCO调整步进值可随残留频偏大小自适应调整,还设计了有效减少倒π的方法,算法成功应用于BD-1定位接收机中,在系统要求的各种信号功率、频偏、码偏的组合条件下,误码率均低于10-5;FLL/PLL双环自动切换载波跟踪算法通过对跟踪后的频差与预置门限的比较判断,在设计的双环切换算法控制下,实现在2阶FLL与3阶PLL之间自动切换,满足不同动态条件下载波跟踪的要求,算法已成功应用于BD-2定位接收机,可以满足300m/s速度和4g加速度的动态性能要求,在信号功率为-133dBm条件下,多普勒频率测量精度达到0.7Hz。对于信息同步。在归纳总结各卫星导航定位系统信息格式相同点的基础上,设计通用的位同步与帧同步算法,给出了具体的实现方法和仿真结果。论文对卫星定位接收机同步技术的理论、算法、仿真、测试等方面做了系统深入地研究。所有算法都已成功应用于BD-1、BD-2定位接收机中。论文的工作为下一步研制具有自主知识产权的定位接收机芯片打下了坚实的基础。更多还原

【Abstract】 Satellite navigation and positioning system relates to a country’s political, economic, military fields, and it is very meaningful to protect national interests. In the Satellite navigation and positioning system, receiver is the part directly facing to the user, and the synchronization determines positioning receiver’s performance and implementation of all functions, so the research on the synchronization of satellite positioning receiver is very important. Paper mainly discussed the satellite positioning receiver’s synchronization theory with using the example of BD-1 and BD-2. The major contributions of the dissertation include:For the Pseudo-code synchronization, focus on how to improve PN code synchronization and phase measurement precision. Main factors that affect synchronization precision and Different requirements from active localization way and passive localization way were analyzed.Designed two different PN synchronization and phase measurement algorithm in conditions of low sampling rate. In condition of Commensurate sampling, realized the accurate estimate of PN code phase with the method of least-square linear fitting .Designed two channels signal time subtraction measuring algorithm was successfully applied in BD-1 receiver. In conditions of the signal power P =- 152.6dbW, the time subtraction measurement accuracy is 5ns; Successful used Non-commensurate sampling (NCS) theory to design the NCS PN code synchronization and phase measurement algorithm. Especially, the theory and design for high-precision code NCO were discussed in detail. The algorithm was successfully applied in BD-2 receiver. When code rate was10.23 MHz and signal power was- 133dBm, PN code phase measurement precision was less than 1ns (0.01 chip), that well meet the system’s requirements. Algorithm can also be used in space distance measurement.For the Carrier synchronization. Analyzed the different demands of active localization way and passive localization way. Designed two carrier tracking algorithm. The AFC carrier tracking method obtained offset size and polarity from the PLL’s output, then adjusted the local VCO through the AFC to reduce the residual Frequency offset. This algorithm was successfully applied in BD-1 receiver. FLL/PLL automatically switched carrier tracking algorithm realized switching through the threshold judgment. and it could adapt to different dynamic conditions. The algorithm was successfully applied in BD-2 receiver. Can satisfied BD-2 system dynamic performance requirements(300m/s,4g). When signal power was -133dBm, the precision of Doppler frequency measurement was 0.7 Hz.For the information synchronization, paper introduced information format of the major satellite positioning system and summarized all their similarities, designed universal bit synchronization algorithm and frame synchronization algorithm. The simulation result of bit synchronization and frame synchronization was presented .In this paper, theoretical analysis, simulation, hardware implementation, performance testing were also discussed in detail. These synchronization algorithms has been successfully applied in BD-1, BD-2 positioning receiver, well meet the system performance requirements.更多还原