Abstract's details

SWOT platform stability challenges to maximize KaRIn performances

Carole Dufour (Thales Alenia Space, France)


Fabien d'ESTE (Thales Alenia Space, France); Laia RAMIO-TOMAS (Thales Alenia Space, France); Magali TELLO (Centre National d'Etudes Spatiales, France); Nathalie STEUNOU (Centre National d'Etudes Spatiales, France)

Event: 2023 Ocean Surface Topography Science Team Meeting

Session: Instrument Processing: Measurement and Retracking

Presentation type: Type Poster

Contribution: PDF file


SWOT satellite (Surface Water and Ocean Topography) is born from a cooperation between CNES and NASA, with a platform developed by Thales Alenia Space and a payload under Jet Propulsion Laboratory responsibility. It was launched on December 2022, and after successful commissioning and Calibration / Validation Phase, it began the first global survey of Earth’s surface water and measurements of the circulation patterns of oceans. Thanks to its wide-swath Ka-band radar interferometer, KaRIn (Ka band Radar Interferometer), combined with a nadir altimeter as well as support instruments, it offers a new opportunity for measuring the height of lakes, river and flood zones, and for seeing mesoscale and sub-mesoscale circulation patterns of oceans. Preliminary science data show excellent results, opening new perspectives in hydrology and oceanography fields.

KaRIn interferograms are very sensitive to flight hardware geometry, and especially the relative positions of the reflectors and the sources. Biases or long term variations can be calibrated, but components whose frequency is higher than the orbital pulsation have a negative impact in the performances. As a consequence, platform design has taken special care of the mechanical disturbances injected by the attitude control and transmitted to the payload structure. This has driven the layout of actuators within the satellite, as well as the command laws to be used during mission.
Impact on science data accuracy has been monitored through a dedicated stability criterion which includes the 3 major components of the instrument geometry: the mast elastic roll, the phase impact of the geometrical displacement of the sources and antennas, and the variation of the baseline length. Given the scales of the instrument, the associated flexible modes have low frequency and low damping, resulting into sharp resonances and long transients: a dedicated approach was necessary to tackle the vibratory challenges on SWOT.

This paper presents the SWOT stability context, the platform optimizations chosen to reduce the disturbances and the methodology applied at satellite level to assess the performances.

Poster show times:

Room Start Date End Date
Esperanza Beach Room (Lobby) Wed, Nov 08 2023,16:15 Wed, Nov 08 2023,18:00
Esperanza Beach Room (Lobby) Thu, Nov 09 2023,14:00 Thu, Nov 09 2023,15:45
Carole Dufour
Thales Alenia Space