BDS real-time 100 picosecond level single difference time and frequency synchronization method

doi:10.11947/j.AGCS.2024.20230353

Abstract

Abstract:

High precise time-frequency transfer and time synchronization services have become a research focus in GNSS applications. Scholars have conducted numerous studies on time-frequency synchronization models, algorithms and related applications. We propose adifferential precise time transfer model based on carrier phase observations, and establish a BeiDou navigation satellite system real-time 100 picosecond level differential time and frequency synchronization system. With the time transfer results of the fiber optic links as reference, differential precise time and frequency synchronization performance is validated. the standard deviation of the BDS real-time pulse per second results is better than 100 ps. What's more, the time deviation of the time link within 7 days is better than 70 ps. In terms of frequency stability, modified Allan deviation of 10⁴ seconds can reach the level of 10^－15, and the long-term frequency stability reaches the level of 10^－16. Additionally, the frequency stability of BDS is comparable to that of GPS, which is of valuable significance for further expanding the application of BDS in the time and frequency community.

Key words: BDS, carrier phase single difference, precise time and frequency transfer, real-time time synchronization

CLC Number:

P228

Chuang SHI, Wei SONG, Fu ZHENG, Haoyuan WANG, Yuzhuo WANG, Aimin ZHANG, Weiming TANG. BDS real-time 100 picosecond level single difference time and frequency synchronization method[J]. Acta Geodaetica et Cartographica Sinica, 2024, 53(5): 869-878.

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基线	基站接收机类型	用户站接收机类型	距离/km
USN8-USN7	SEPT POLARX5TR	SEPT POLARX5TR	0
SPT0-ONSA	SEPT POLARX5TR	SEPT POLARX5TR	67.90
BJCC-BJ01	PD51A	PD318-T	0.01
BJCC-BJ02	PD51A	PD318-T	35.20

解算策略	DPT时频传递	终端时频同步
卫星系统	BDS-3、GPS
采样率/s	30	1
观测量	SPT0-ONSA：无电离层组合USN8-USN7：非组合	BJCC-BJ02：无电离层组合BJCC-BJ01：非组合
高度角/（°）	15
解算模式	事后解算	实时解算
卫星轨道&钟差	广播星历
电离层延迟改正	USN8-USN7、BJCC-BJ01：OFF；SPT0-ONSA、BJCC-BJ02：无电离层组合
对流层延迟改正	USN8-USN7、BJCC-BJ01：OFF；SPT0-ONSA、BJCC-BJ02：Saastamoninen

测站	TOT（L1）	TOT（L2）	校准不确定度uCal0
USN7	155.6	149.3	1.2
USN8	202.6	197.4	1.2