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ERS PRARE Precise Orbit Product (ERS.ORB.POD/ERS.ORB/PRC)

Data

12 Jul 2019

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blue arrow DESCRIPTION

The precise orbit results from a data reduction process in which all available tracking data (Single-Lens Reflex, radar altimeter crossovers, PRARE range and Doppler data) and most accurate correction, transformation and dynamical models are taken into account and in which high level numerical procedures are applied.

These orbits are "optimal" achievable representations of the real orbital motion under the circumstances of tracking situation and the "state of the art" model situation. The precise orbit product for the ERS satellites are the satellite ephemeris (position and velocity vector) including time tag, given in a well-defined reference frame, together with the nominal satellite attitude information and a radial orbit correction.

Several orbit solutions are currently distributed:

  • A new set of ORB POD (Precise Orbit Determination - REAPER v2) computed with the most updated model standards for the complete ERS-1 and ERS-2 mission.
  • A previous set of ORB POD (REAPER v1) data already available on the ESA dissemination site since 2014, covering the ERS-1 full mission and the ERS-2 mission up to July 2003.
  • ORB PRC which is the original Precise Orbit dataset computed during the ERS mission operations for ERS-1 and ERS-2.

In the new POD dataset (REAPER v2) for the ERS-1 and ERS-2 missions, two different orbit solutions are provided together with the combined solution to be used for processing of the radar altimeter measurements and the determination of geodetic/geophysical products: those computed by DEOS (Delft Institute of Earth Observation and Space Systems), and those generated by ESOC (European Space Operations Centre) using different software (GEODYN and NAPEOS respectively).

Careful evaluation of the various solutions of REAPER v2 has shown that the DEOS solution for both ERS-1 and ERS-2 has the best performance and is recommended to be used as reference. See the ERS Orbit Validation Report.

For the previous version of the POD data set (REAPER v1), with ERS-2 mission data only up to 2003, three different orbit solutions together with the combined solution are available. These precise orbits for ERS-1 and ERS-2 have been computed at DEOS, ESOC, and GFZ (Deutschen GeoForschungsZentrums) using different software and different altimeter databases. Combined solutions have been created using three individual solutions for each satellite.

All orbits were derived using consistent models in the same LPOD2005 terrestrial reference frame. These new orbit solutions show notable improvement with respect to DGME04 orbits (Scharroo and Visser, 1998). Thus, RMS crossover differences of new orbits improved by 4-9 mm. Careful evaluation of the various solutions has shown that the combined solution for both ERS-1 and ERS-2 has the best performance.

All POD orbit files (REAPER v1/v2) are available in SP3c format.

blue arrow DETAILS

blue arrow DATA SET SPECIFICATIONS

Spatial coverage: 

82 N, -82 S, -180 W, 180 E

Temporal coverage:

1991-08-03 - 2011-07-18

(See Products Availability Table below for coverage of each dataset)

Date of launch:
ERS-1: 1991-07-17 , ERS-2: 1995-04-21
Operators:
ESA
Mission status:
completed
Orbit height:
782 to 785 km
Orbit type:
Sun-synchronous
Swath width:
5 km

blue arrow PROCESSING LEVEL

level 1,

blue arrow APPLICABLE TERMS & CONDITIONS

Utilisation of this data is subject to ESA's Earth Observation Terms and Conditions

READ T&C

blue arrow RESOURCES

ERS Orbit Validation Report (REAPER v 2)
Technical Note
ERS POD Product Specifications document (REAPER v1)
Product Specification
ERS-1 and ERS-2 Orbit Validation Report (REAPER v1)
Product Specification
ERS D-PAF Altimeter and Orbit Global Products Manual (ORB.PRC)
User Manual
REAPER Product Handbook
User Manual
More PRARE Documents
Other
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