基于钟驾驭模式的定时接收机绝对校准  

Absolute calibration of timing receiver based on clock-steering model

作　　者：朱峰[1,2,3] 李孝辉[1,2] 张慧君[1,2] 

机构地区：[1]中国科学院国家授时中心,西安710600 [2]中国科学院精密导航定位与定时技术重点研究室,西安710600 [3]中国科学院研究生院,北京100039

出　　处：《仪器仪表学报》2014年第9期1946-1954,共9页Chinese Journal of Scientific Instrument

基　　金：国家自然科学基金委国家重大科研仪器设备研专项(61127901);西部之光人才培养项目资助

摘　　要：卫星导航中定时接收机的延迟校准一直是个难点,不同类型接收机的校准方法有所不同,需要研究有针对性的解决方法。在对无1PPS信号输入接收机分析的基础上,研究了基于钟驾驭模式接收机延迟的绝对校准方法。相比NRL实验室选用的有1PPS信号输入接收机而言,钟驾驭模式的接收机延迟除了受伪距测量、硬件链路时延影响以外,还与系统时钟分辨率有关,时钟分辨率越高的接收机其本地钟向卫星钟的驾驭性能越好,对应的通道延迟也越小。试验选用模拟器Spirent GSS8000分别对Novatel和Septentrio两款不同型号的接收机进行校准,受跟踪环路和射频滤波器群时延的影响,不同型号接收机在不同频段和不同伪码下的延迟存在差异。Novatel接收机对C/A码1.2 ns的不确定度优于P码的1.5 ns,Septentrio接收机L1频段1.5 ns的不确定度大于L2频段的1.3 ns,但由于系统时钟的不稳定,双频电离层改正后Septentrio接收机的不确定度4.3 ns要高于Novatel的3.8 ns。Delay calibration of timing receiver is always a difficult point in satellite navigation, and the calibration methods for different types of receivers are also different, which should be studied with pertinence solutions. On the basis of analyzing the timing receivers without external 1PPS input, the paper studies an absolute calibration method of receiver delay based on clock-steering model. Compared with the receiver with external 1PPS input used by NRL, the receiver delay based on clock-steering model is not only affected by pseud- orange measurement and hardware link delay, but also related to the resolution of system clock ; thus higher clock resolution leads to bet- ter steering performance of the receiver, which corresponds to lower channel delay. Spirent GSSS000 was chosen as the GNSS hardware simulator to absolutely calibrate the receivers of Novatel and Septentrio in the experiment. Affected by tracking loop and RF filter group delay, the delays of various receivers for different frequency bands and PRN codes are different. The uncertainty of Novatel receiver for C/A code is 1.2 ns, which is better than the 1.5 ns for P code; and the uncertainty of Septentrio receiver in Ll-band is l. 5 ns, which is higher than the 1.3 ns in L2-band. However, due to the instability of the system clock, the ionosphere-free combined uncertainty of Septentrio is 4.3 ns, which is higher than the 3.8 ns of Novatel receiver.

关 键 词：钟驾驭 绝对校准 接收机延迟 TTC 伪距 

分 类 号：TH714.1[机械工程—测试计量技术及仪器]