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New GNSS L1B RINEX data release for Sentinel-1, -2, and -3

07 February 2018

In response to scientific user recommendations and in agreement with the European Commission, a new Sentinel GNSS L1B RINEX user product has been officially released for the Sentinel-1, -2 and -3A satellites from the Copernicus Data Hub service.

Users will be able to access the GNSS RINEX data from a dedicated Pre-operational Hub starting from 13 February 2018 through the Open Hub web portal. The data will be moved to the Open Access Hub in the following months.

The full mission data set is available for each of the Sentinel missions and is regularly completed on a daily basis.

Sentinel-3B data will be available after the successful commissioning of the satellite (expected not before second quarter of 2018).

The Sentinel GNSS L1B RINEX product format is described in the Product Format Specification (PFS) document.

While it is probably not as well-known as the main scientific instrument payloads on-board the satellites, the Sentinel-1, -2 & -3 missions incorporate a couple of dual frequency GPS receivers to support the precise determination of the satellite orbit, needed for the processing of the scientific data acquired by the main instruments. Up to now, the GNSS L1B data generated by these dual frequency GPS receivers were only circulated inside the Ground Segment of the Copernicus project, and in particular to the Copernicus Precise Orbit Determination Service, in charge of generating the precise orbits of these satellites.

The GNSS L1B RINEX data has several scientific uses, the most obvious being the study of orbit determination methods and, in particular, the effect of the non-conservatives forces (solar radiation, albedo, atmospheric drag, radiation pressure, etc.).

Other uses include:

  1. Ionosphere characterization, as the dual-frequency GPS measurements contain information about the TEC (Total Electron Content) in the ionosphere
  2. Gravity Field modelling, as it is possible to determine the time-variable part of the gravity field
  3. Geodesy, as the inclusion of LEO measurements into global GNSS processing is supposed to be advantageous for the determination of global parameters

Most of these applications require several ancillary data to allow performing POD. This includes:

  1. Geometrical description of the satellite (sizes and properties of panels)
  2. Attitude law of the satellite
  3. Location and orientation of the GPS antennas
  4. Calibration of the GPS antennas (phase centre offset and phase centre variations)
  5. Time and size of the manoeuvres
  6. Evolution of the mass (which changes after each manoeuvre) and the location of the centre of mass

The above ancillary data will soon be made available on Sentinel Online.

By releasing the Sentinel GNSS RINEX files and the other ancillary files, the Copernicus Programme aims at supporting the scientific community involved in many geodetic applications worldwide and encourage new uses for the Sentinels GNSS data, maximising the missions' return and becoming a reference for GNSS processing.