Global Transmission Services 2 (GTS-2) - 01.09.14

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ISS Science for Everyone

Science Objectives for Everyone Global Transmission Services 2 (GTS-2) is a technology experiment for the test, validation and demonstration of radio transmission techniques for the synchronization of earth-based clocks and watches from the ISS. In addition the GTS data services, based on a unique coding scheme, could ultimately lead to commercial services, such as blocking of stolen cars or lost credit cards, directly from space.

Science Results for Everyone Information Pending

This content was provided by Felix Huber, Ph.D., and is maintained in a database by the ISS Program Science Office.
Information provided courtesy of the Erasmus Experiment Archive.

Experiment Details


Principal Investigator(s)

  • Felix Huber, Ph.D., Steinbeis Transferzentrum Raumfahrt, Gaufelden, Germany
  • Co-Investigator(s)/Collaborator(s)
    Information Pending


    German Aerospace Center (DLR), Cologne, , Germany

    Sponsoring Space Agency
    European Space Agency (ESA)

    Sponsoring Organization
    Information Pending

    Research Benefits
    Information Pending

    ISS Expedition Duration:
    April 2007 - October 2009

    Expeditions Assigned

    Previous ISS Missions
    Information Pending

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    Experiment Description

    Research Overview

    • The Global Transmission Services 2 (GTS-2) is designed to investigate the possibilities of transmitting a time signal from the International Space Station (ISS) to synchronize clocks on the ground.

    • Time signal stations on Earth usually broadcast their information at long wavelengths. Watches and clocks synchronize themselves with these signals by activating their receivers typically once per day or after turn-on.

    GTS is transmitting a UTC time signal from the Station via an external antenna with a broad antenna pattern. The Station?s orbit means that this signal covers almost the whole globe every day. It can be received at any location several times daily, for 5-12 min at a time, strong enough for even small wrist watches. GTS also broadcasts the Station?s current orbital position, so clocks know their local time zone.

    GTS-2 will verify the performance and accuracy of a time signal broadcast to Earth from low orbit under real space operational conditions. GTS-2 will also measure the signal quality and data rates on the ground and measure disturbing effects such as Doppler shifts, multi-path reflections, shadowing and elevation effects.

    GTS-2 is a continuation of the Global Transmission Services (GTS) experiment, which will be possible when a new electronic unit is launched on Progress flight 22P to the ISS. On 5 December 2005, the current GTS was re-activated, after a long time of theoretical investigations and practical tests to find out the reasons and successfully introduce corrective measures for the weaker than expected transmitted signal strength experienced by GTS receivers on the ground.

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    Space Applications
    Information Pending

    Earth Applications
    Information Pending

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    Operational Requirements
    Information Pending

    Operational Protocols
    Information Pending

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    Results/More Information
    Information Pending

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    Related Websites

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    image NASA Image: ISS003E5477 - Cosmonaut Vladimir Dezhurov of Rosaviakosmos, Expedition Three flight engineer, holds a Global Time System (GTS) electronics unit in the Zvezda Service Module.
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