Optical two-way timing system for space geodesy applications

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A21340%2F16%3A00243210" target="_blank" >RIV/68407700:21340/16:00243210 - isvavai.cz</a>

Result on the web

<a href="http://dx.doi.org/10.1109/EFTF.2016.7477788" target="_blank" >http://dx.doi.org/10.1109/EFTF.2016.7477788</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1109/EFTF.2016.7477788" target="_blank" >10.1109/EFTF.2016.7477788</a>

Result language

angličtina

Original language name

Optical two-way timing system for space geodesy applications

Original language description

Until now, time itself is not an observable in space geodesy. The major reason for this fact is the considerable difficulty to keep track of the phase of the clock oscillation between the point of origin and the point of the measurement. However, if geodesy will attempt to provide a reference frame fully based on general relativity, a proper treatment of time is mandatory. The Geodetic Observatory Wettzell is currently in the process to modernize the timing system such that the phase of the master clock can be established at all times. The ultra-short pulses of an optical frequency comb are transporting both time and frequency from the master clock of the observatory to the individual space geodetic techniques, namely Very Long Baseline Interferometry (VLBI), Satellite Laser Ranging (SLR) and Global Navigation Satellite System (GNSS), using a two-way approach. In order to verify the functionality of this system not only in sense of delay stability but also accuracy, we have developed a new TWTT system based on the exchange of timing signal via standard optical telecommunications Small Form-factor Pluggable (SFP) transceivers to transfer timing information between two or more terminals with the accuracy below 1 ps via optical fibers of a length of up to several tens of kilometers. The heart of the measurement device is an event timing module using surface acoustic wave filters as a time interpolator, which allows the registration of the times-of-arrival of electrical pulses with sub-picosecond timing resolution, linearity and stability. These pulses are derived from the optical signal, which is used for the communication between the terminals. Great care was taken in order to minimize terminal internal delays instability, which can be the result of temperature changes inside terminals. The design, applications and the first experiments at GO Wettzell will be discussed.

Czech name

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Czech description

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Type

D - Article in proceedings

CEP classification

—

OECD FORD branch

20201 - Electrical and electronic engineering

Project

—

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2016

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Article name in the collection

2016 European Frequency and Time Forum (EFTF 2016)

ISBN

978-1-5090-0720-2

ISSN

—

e-ISSN

—

Number of pages

6

Pages from-to

121-126

Publisher name

Institute of Electrical and Electronics Engineers

Place of publication

Brighton

Event location

York

Event date

Apr 4, 2016

Type of event by nationality

WRD - Celosvětová akce

UT code for WoS article

000386307700033