High-precision optical fiber time-frequency signal synchronization network

Abstract

A high-precision fiber time frequency signal synchronization network comprises fibers, N switches and M time frequency signal sources, where N is a positive integer larger than 2 and M is a positive integer larger than 1. Each switch and time-frequency signal source is a network node, forming a total of N + M network nodes, in which each of the M time-frequency signal sources is connected with the adjacent two switches through the fiber, and each of N switches is connected to other different switches or time-frequency sources via at least three different fibers. The fibers are used as the transmission medium of the time-frequency signal synchronization network, and the accuracy of the time frequency signal homologous synchronization in the whole network is very high, and the fiber link stabilization and the time-frequency signal transmission are separated, so that the transparent transmission of the time frequency signal and the network protection switching are achieved.

Description

technical field [0001] The invention relates to a time-frequency signal synchronization network, in particular to a high-precision optical fiber time-frequency signal synchronization network. Background technique [0002] Contemporary society is already an information-driven networked society, and navigation and positioning, wireless communication, the Internet, and distributed power grids have become indispensable and basic components of social life. An undeniable fact is that these technologies all rely on the clock synchronization network, which serves as the technical basis and provides high-precision time-frequency reference signals for these applications. [0003] The most important clock synchronization solution today is the satellite-borne atomic clock broadcast to the world by means of space-based navigation and positioning systems (GNSS) such as GPS / Beidou, followed by various methods such as e-Loran, IEEE1588v2, DCF77, and NTP. The accuracy is shown in Table 1. ...

AI Technical Summary

Problems solved by technology

[0006] These methods are difficult to meet the needs of next-generation applications

First of all, the GNSS system with slightly higher precision has shortcomings such as weak signals, multipath errors, and area rejection caused by it. Secondly, in terms of accuracy, it is increasingly necessary to have cm or even mm-level positioning accuracy and ps-level time synchronization accuracy. Even in many fields, frequency homology stability of the order of 1E-15 in the short term and 1E-18 in the long term is required

For example, the coherent fusion of multistatic radars can be realized only after the time synchronization accuracy reaches the ps level and the frequency is homogeneous and phase-coherent, so as to truly improve the detection and interference capabilities of existing radars; in addition, the second stability of optical clocks has entered 1E -15 level, in order to use optical clocks to rewrite the secondary definition of seconds at a higher level of precision, it is necessary to compare optical clocks around the world at this level; today's emerging driverless field also requires higher Accurate positioning can promote the success of its promotion and application, because the current GPS-based positioning accuracy of Google's driverless cars and auxiliary equipment such as radars and cameras can achieve a safe driving mileage of about 150,000 kilometers, although for a single car, this value is already It’s amazing, but if you consider the effective safe mileage, it’s far from enough. For example, in a morning rush hour in Shanghai, the effective safe mileage is about 30 million kilometers (1 million cars travel an average of 30 kilometers at the same time). If you are driving a car, you can easily see that the safe mileage of 150,000 kilometers is far from enough

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