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Autonomous and Rechargeable Microneurostimulator Endoscopically Implantable into the Submucosa

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ACES microwave link requirements.

P M Uhrich¹, P Guillernot, P Aubry

¹Lab. Primaire du Temps et des Frequences, Bur. Nat. de Metrol.

IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control

|February 2, 2008

Summary

This summary is machine-generated.

The Atomic Clock Ensemble in Space (ACES) payload on the International Space Station (ISS) requires a microwave link (MWL) with sub-picosecond stability for precise time transfer. This ensures accurate positioning and speed measurements of the ACES clocks.

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Area of Science:

Space Science
Atomic Physics
Metrology

Background:

The Atomic Clock Ensemble in Space (ACES) is a European Space Agency payload for the International Space Station (ISS).
It features two advanced atomic frequency standards: a space hydrogen maser (SHM) and a cold atom caesium clock (PHARAO).

Purpose of the Study:

To define the stringent requirements for the microwave link (MWL) connecting the ACES payload to Earth-based clocks.
To ensure the high-precision performance of atomic clocks in space.

Main Methods:

Analysis of ISS orbital characteristics and their impact on microwave link stability.
Calculation of required clock stability based on acceptable noise levels for the MWL.

Main Results:

The MWL must achieve sub-picosecond stability during each ISS pass over an Earth station.
Long-term stability requirements are at the level of 1x10^-16 or better over one day.
Precise knowledge of the ACES clock's position (meter level) and speed (mm/s level) is necessary.

Conclusions:

Meeting these MWL requirements pushes the boundaries of current microwave and optical technologies.
Successful implementation is crucial for the scientific objectives of the ACES mission, including advanced time and frequency transfer.