Optical clock technologies for global navigation satellite systems
GPS Solut., vol. 25, art. 83, doi:10.1007/s10291-021-01113-2 (2021).
© The Author(s) 2021.
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Future generations of global navigation satellite systems (GNSSs) can benefit from optical technologies. Especially optical clocks could back-up or replace the currently used microwave clocks, having the potential to improve GNSS position determination enabled by their lower frequency instabilities. Furthermore, optical clock technologies - in combination with optical inter-satellite links - enable new GNSS architectures, e.g., by synchronization of distant optical frequency references within the constellation using time and frequency transfer techniques. Optical frequency references based on Doppler-free spectroscopy of molecular iodine are seen as a promising candidate for a future GNSS optical clock. Compact and ruggedized setups have been developed, showing frequency instabilities at the 10-15 level for averaging times between 1 s and 10,000 s. We introduce optical clock technologies for applications in future GNSS and present the current status of our developments of iodine-based optical frequency references.
1 German Aerospace Center (DLR), Institute of Space Systems, Bremen, Germany
2 Center of Applied Space Technology and Microgravity, University of Bremen, Bremen, Germany
3 Ferdinand-Braun-Institut gGmbH, Leibniz-Institut für Höchstfrequenztechnik, Berlin, Germany
4 Institute of Physics, Humboldt-Universität zu Berlin, Berlin, Germany
5 Menlo Systems GmbH, Martinsried, Germany
6 SpaceTech GmbH, Immenstaad, Germany
Optical clock, Iodine reference, Space instrumentation, Future GNSS