相位噪声对Cn频段导航信号载波相位测量精度的影响分析  

The influence of phase noise on carrier phase measurement in Cn-band navigation signal

作　　者：张志敏 克兢 王雪[3] 贾晓辉 ZHANG Zhi-min;KE Jing;WANG Xue;JIA Xiao-hui(National Time Service Center,Chinese Academy of Sciences,Xi’an 710600,China;University of Chinese Academy of Sciences,Beijing 100049,China;Xidian University,Xi’an 710600,China)

机构地区：[1]中国科学院国家授时中心,西安710600 [2]中国科学院大学,北京100049 [3]西安电子科技大学,西安710600

出　　处：《时间频率学报》2023年第2期116-129,共14页Journal of Time and Frequency

基　　金：中国科学院“西部之光”人才培养计划“西部青年学者”资助项目(XAB2021YN20)。

摘　　要：Cn频段(5010~5030 MHz)是除L频段外唯一受国际电联(ITU)保护的导航频段,也是当前转发式系统的试验频段,在Cn频段开展导航业务可解决目前L频段所面临的频谱拥挤和易受干扰等问题。转发式卫星导航试验系统要实现“分米级定位,纳秒级授时”的目标,需要利用载波环进行高精度测距。相比L频段,Cn频段落地电平较低,更易受干扰,因而针对Cn频段导航信号进行载波相位测量精度的影响分析至关重要。本文首先研究了相位噪声的生成方法,接着利用锁相环的线性模型研究了输入端、内部振荡器相位噪声对锁相环跟踪精度的影响,分析了噪声带宽、相干积分时间对PLL相位抖动的影响,对于后续接收机的设计具有较强的借鉴意义。最后通过实测信号验证了噪声带宽对锁相环跟踪精度的影响。研究结果表明:相位噪声会引起环路明显的相位抖动,频率白噪声和频率随机游走噪声所引起环路的相位抖动随噪声带宽Bn先递减后递增,随相干积分时间T而递增。本文结论为后续C频段接收机的设计实现提供了有价值的借鉴。Cn-band(5 010~5 030 MHz) is the only navigation frequency band protected by the International Telecommunication Union(ITU) except L-band, and it is also the experimental band of the current ZFS system.Carrying out navigation service in Cn-band can solve the problems of spectrum congestion and easy interference faced by L-band at present. In order to achieve the goal of “decimeter positioning and nanosecond timing”, the ZFS system needs to use the carrier loop for high-precision ranging. Compared with L-band, Cn-band has a lower landing power and is more susceptible to interference, so it is very important to analyze the influence of Cn-band navigation signals on ranging. Based on the basis of the generation method of phase noise, the influence of input and internal oscillator phase noise on the tracking accuracy of PLL was studied with the linear PLL model, and the influence of noise bandwidth and coherent integration time on PLL phase jitter was analyzed, the influence of noise bandwidth on the tracking accuracy of PLL was verified by RF signals. The results shown that the phase noise can cause obvious phase jitter of the loop, and the phase jitter of the loop caused by frequency white noise and random walk noise decreases first and then increases with the noise bandwidth Bn, and increases with the coherent integration time. The study results provide a foundation for the design and implementation of the C-band receiver.

关 键 词：Cn频段 相位噪声 噪声带宽 相干积分时间 相位抖动 

分 类 号：TN967.1[电子电信—信号与信息处理]