Minimize POD system baselines & reprocessing campaigns

The following table shows the baselines of Copernicus POD systems with the deployment date and a summary of the change description included in the new system which affect the Sentinel-3 mission. Additionally, the baselines used for the S3PODIPF in charge of the generation of NRT Restituted Orbits (SR___ROE_AX) is included below. A full description of the changes is included in the Product Handbook. Only changes that might affect the quality of POD products for final users are outlined here below.

Table 1: Copernicus POD System baselines affecting Sentinel-3
Version Date Change description
Sentinel-3A launch (17/02/2016)
SPOD_SYSTEM_v1.0.0 18/02/2016 Updated GPS DBs and GPS ANTEX (igs08.atx)
Included PassSegmentList module to compute Pass Segments for ILRS tracking
SPOD_SYSTEM_v1.0.1 08/03/2016 Updated Sentinel DBs for Sentinel-3A to align to launch values
SPOD_SYSTEM_v1.0.2 11/03/2016 Corrected frame of reference transformation to Satellite Frame of Reference for S-3
SPOD_SYSTEM_v1.0.3 05/04/2016 Corrected decoding of NAVATT files for generating quaternions using Packet Generation Timestamp
SPOD_SYSTEM_v1.0.4 06/04/2016 Corrected Platform Data File frame of reference
SPOD_SYSTEM_v1.0.5 13/04/2016 Updated ANTEX including S-3A GPSA receiver
Updated Sentinel transponder DB with corrected information on SLR antenna
Add ILRS stations 1824, 1888, 1889, 1990 and 7827 to the station DB
SPOD_SYSTEM_v1.0.6 20/04/2016 Updated Sentinel transponder DB with corrected location of GNSS antennae for Sentinel-3A
Updated ANTEX including S-3A GPSA receiver using new antenna location, computed from 8 days of NTC executions
Change timeliness of S3 NTC to 25 days
SPOD_SYSTEM_v1.0.7 21/04/2016 Change Quality flags thresholds of Sentinel-3A to align to S-1A and S-2A values
Update Sentinel transponder DB to update reference point of SRAL antenna
SPOD_SYSTEM_v1.0.8 30/05/2016 Solve issue causing occasional incorrect Orbit Number in EOF NRT products
SPOD_SYSTEM_v1.0.10 06/09/2016 Update SLR stations selection policy to exclude tracking from biased stations
Update rsgaConv.bin to make it more robust against missing info in Solar Activity File
Change Orbit Determination configuration for S-3 STC and NTC to use multi-tracks in case of manoeuvre
Change timeliness of hourly RINEX for CNES to 4.5 hours after sensing time
SPOD_SYSTEM_v1.1.0 20/10/2016 Add CMC handling in sp3 orbit generation
Correct expression of the solar radiation pressure partial derivative in the Box Wing Model
SPOD_SYSTEM_v1.1.1 10/11/2016 Deploy new ANTEX with S-3A information computed by 90 days of residuals
The timeliness and coverage of the Medium Orbit Ephemerides Orbit Files (AUX_MOEORB) and Preliminary Platform Data Files (AUX_PRLPTF) has been adapted to the expectations of the S3 PDGS, such that the product with coverage d-2 at 22 hours to d-1 at 24 hours (GPS time) will be delivered before noon on day d.
The coverage of the Precise Orbit Ephemerides Orbit Files (AUX_POEORB) and Precise Platform Data Files (AUX_PRCPTF) has been changed to d-1 22:00 until d+1 00:00 (GPS time)
SPOD_SYSTEM_v1.2.0 13/12/2016 Include tool to reduce SAR Annotation Files, SAD PDI files, overlaps and duplicates from archive (affecting reprocessing)
The determination period of NTC products has been reduced from 48 hours to 32 hours (26 hour coverage + 3 hours in each border)
The minimum number of observations per epoch threshold has been modified from 4 to 1 for quality flagging (more appropriate for dynamic orbit determination).
New gravity field model EIGEN.GRGS.RL03.v2.coef
Deploy first version of SLR ANTEX for S-3A based on LRR geometry
SPOD_SYSTEM_v1.2.1 16/01/2017 The filename of CPF gets the epoch directly from the CPF itself
SPOD_SYSTEM_v1.3.0 16/02/2017 Deploy a new GPS ANTEX (igs14_1935.atx)
SPOD_SYSTEM_v1.3.1 27/03/2017 Update header for ITRF14 realization in sp3 orbits generation
SPOD_SYSTEM_v1.3.2 18/05/2017 Change in CNES RINEX generation process to guarantee continuity between different executions
SPOD_SYSTEM_v1.3.3 29/05/2017 New antex file deployed: sen08_1950.atx
New GPS antex file deployed: igs14_1949.atx
Change POD NTC/STC processing chain to avoid using broadcast navigation message information (BRDC) info if IGS/STC orbits available
SPOD_SYSTEM_v1.3.4 19/06/2017 Generation and distribution of daily operational RINEX
SPOD_SYSTEM_v1.3.5 27/07/2017 Include option to apply Differential Code Biases when using observations different than P1 and P2
Use 24H orbit file prediction for S3PODIPF near end of interval
Use Earth Orientation Parameters (EOPs) provided by EGP for S3PODIPF
Align all EGP clocks to broadcast navigation message for S3PODIPF
SPOD_SYSTEM_v1.3.6 22/08/2017 Implement changes related to Post-Seismic Deformation (PSD)
New antex file deployed with Sentinel-2B 90-residual computation: sen08_1963.atx
New station database deployed pointing to ILRS2014 coordinate file (ILRS2014-ESOC.crd)
SPOD_SYSTEM_v1.3.7 11/10/2017 Upgrade IPF to update RINEX files version to 3.03
Start processing GNSS RINEX for Copernicus Data Hub, including dissemination mechanisms
SPOD_SYSTEM_v1.3.8 30/10/2017 The S-3B box-wing model has been aligned to S-3A
SPOD_SYSTEM_v1.3.9 08/11/2017 Preliminary version of DORIS processing chain (DORIS-only and DORIS+GPS orbits)
Implement half cycle bias correction reading info from GPS Auxiliary Data (s-1,-3 and s-2b) or GPS Channel Status data (s-2a)
SPOD_SYSTEM_v1.4.0 28/11/2017 Removal of temperature effects and configure HW bias to 23.5 m in the decoding tool (IPF)
Correction of half-cycle ambiguities in the decoding tool (IPF)
Update location of S-3B antenna in DB
SPOD_SYSTEM_v1.4.1 29/01/2018 Create processing chain to process DORIS operationally and DORIS+GPS
Prepare a new version of S3PODIPF with changes to do not use L2C with S-3B during commissioning
Create new S-3 interface from CPOD/EGP and LAND centre for S-3B

SPOD_SYSTEM_v1.4.0

28/11/2017

Removal of temperature effects and configure HW bias to 23.5 m in the decoding tool (IPF)

Correction of half-cycle ambiguities in the decoding tool (IPF)

Update location of S-3B antenna in DB

SPOD_SYSTEM_v1.4.1

29/01/2018

Create processing chain to process DORIS operationally and DORIS+GPS

Prepare a new version of S3PODIPF with changes to do not use L2C with S-3B during commissioning

Create new S-3 interface from CPOD/EGP and LAND centre for S-3B

SPOD_SYSTEM_v1.4.2

26/02/2018

Create chains to generate and distribute data for Sentinel OnLine

New antex file with small corrections deployed: sen08_1989.atx

New satellite & transponder DBs with small corrections deployed: s3satellite1990100.dat & s3transp1990100.dat

New s3b icdb was deployed: s3bicdb_1969.xml

Corrections on S3PODIPF for redundant receiver:

  • The generation of imt2gps file
  • Half cycle ambiguity
  • Decoding S2 L0 data

Sentinel-3B Launch (25/04/2018)

SPOD_SYSTEM_v1.4.3

08/05/2018

Update the SVL server IP address to trinity server

New satellite & transponder DBs with updated NORAD, COSPAR and SIC IDs for Sentinel-3B: s3satellite2000100.dat & s3transp2000100.dat

SPOD_SYSTEM_v1.5.0

05/06/2018

Generate quaternions file merging real and simulated attitudes during data gaps.

Implement new mechanisms to fill EGP/magic gaps in case of FTP/internet failure

SPOD_SYSTEM_v1.5.1

04/10/2018

Preparation of the system for the processing of Sentinel-3B.

Implemented a satellite re-radiation model

Updated sentinels ANTEX to include information for S3B and updated sentransp.dat to include SLR antex for S3B (the same that is used by S3A)

Updated reference orbit of S3B

Updated IPF to correctly decode L0 data from both redundant and nominal receivers simultaneously.

SPOD_SYSTEM_v1.5.3

07/11/2018

Update the GPS databases to align them with the latest changes in the GPS constellation.

 

Table 2: S3PODIPF baselines
Version Date Change description
S3PODIPF_v02_03 13/06/2014 S3PODIPF AR close-out
S3PODIPF_v02_04 18/12/2014 Process NAVATT v3.0 data
S3PODIPF_v02_05 30/01/2015 Updates in JobOrder's Tags, TaskTables and Product List to align to documentation
S3PODIPF_v02_06 03/07/2015 Several NAPEOS updates to include up-to date models (IERS2010 standards together with new gravity field mode (EIGEN6S) and ocean tide model (EOT11a))
S3PODIPF_v02_07 25/09/2015 NAVATT inputs are set to optional instead of mandatory
S3PODIPF_v02_08 04/12/2015 Fix bug on scaling IMT and decoding performance
S3PODIPF_v02_09 11/01/2016 Task tables modified (Retrieval Mode set to LatestValCover)
Sentinel-3A launch (17/02/2016)
S3PODIPF_v02_10 07/03/2016 Change reading process of EOP file
S3 NAPEOS attitude corrected, in line with real data attitude
S3PODIPF_v02_11 17/03/2016 Changes in retrieval modes in task tables
Change configuration of RINEX writer to set correct interval as specified in the Job Order
S3PODIPF_v02_12 06/04/2016 Corrected selection of RGSA
NAVATT time decoding issue solving 1-second time tagging shift with respect to simulated attitude
S3PODIPF_v02_13 03/05/2016 File permissions issue fixed
XML format issue fixed
NAPEOS input/output folders made configurable
S3PODIPF_v02_14 10/05/2016 File permission issue fixed
Fix bug affecting products finishing in 59.5 second
S3PODIPF_v02_15 30/05/2016 NAPEOS input/output folders read from S3PODIPF L1B processing folder
S3PODIPF_v02_16 27/06/2016 Correction of issue with platform data file (occasional wrong number of elements in the file)
S3PODIPF_v02_17 06/09/2016 Increase its robustness against unexpected values in the Solar Activity File retrieved from NOAA
Change Orbit Determination configuration for S3PODIPF to use multi-tracks in case of manoeuvre
S3PODIPF_v02_18 16/01/2017 The minimum number of observations per epoch threshold has been modified from 4 to 1 for quality flagging (more appropriate for dynamic orbit determination)
New gravity field model EIGEN.GRGS.RL03.v2.coef
A quality check of GNSS input files which was time consuming has been made optional upon user request, reducing slightly processing time.
S3PODIPF_v02_19 05/09/2017 Use 24H GPS orbit file prediction near end of interval instead of GPS broadcast navigation message, thus improving their accuracy.
Use Earth Orientation Parameters (EOPs) provided by EGP for S3PODIPF instead of the ones provided by USNO (kept as back-up).
Align all EGP clocks to GPS broadcast navigation message
S3PODIPF_v02_20 30/10/2017
Ready to process S-3B and can be considered part of the frozen pre-launch configuration
The S-3B box-wing model has been aligned to S-3A

 

The following table summarizes the different POD models and settings used by the Copernicus POD Service (at GMV) and CNES.
 

Copernicus POD System baselines affecting Sentinel-3

Analysis Centre

Name

CPOD SERVICE

CNES

Software

Name and version

NAPEOS

ZOOM 5.10

Arc cut

Arc lengths

32 h

36 h

Handle of Manoeuvers

Manoeuvres are calibrated in the POD process

Manoeuvres are calibrated in the POD process

Handle of Data gaps

Yes

Yes

Reference System

Polar motion and UT1

IERS finals2000A.data

IERS14-C04

Pole model

IERS 2010 Conventions

IERS 2010 Conventions (Updates: linear pole model)

Precession/Nutation

IERS 2010 Conventions

IAU 2006/2000A

Satellite Reference

Mass and centre of gravity

Variable with input from FOS

Variable with input from FOS

Attitude Model

Quaternions

Nominal attitude law

GPS antenna reference point (X,Y,Z)

Sentinel-3 properties for GPS POD

Adjusted

GPS antenna orientation (Euler angles, Z,Y,X)

Sentinel-3 properties for GPS POD

Nadir Pointing

Gravity

Gravity field (static)

EIGEN.GRGS.RL03.v2 (120x120)

GRACE+SLR CNES/GRGS RL04 [EIGEN.GRGS.RL04.v1 (90x90)]

Gravity field (time varying)

drift/annual/semi-annual piece wise linear terms up to degree/order 50

drift/annual/semi-annual/bias piece wise linear terms up to degree/order 90

Solid Earth tides

applied (IERS 2010)

applied (IERS 2003)

Ocean tides

EOT11a (50x50, 106 tidal constituents)

FES2014

Atmospheric gravity

ATM_GEOSFPIT (64x64)

AOD1B RL06 (100x100)

Atmospheric tides

Ray-Ponte 2003

AOD1B RL06 (100x100)

Earth pole tide

IERS 2010

IERS 2003

Ocean pole tide

IERS 2010

IERS 2010

Third bodies

Sun, Moon, Planets DE405

Sun, Moon, Planets INPOP08

Surface forces and empiricals

Radiation Pressure model

Box-wing model (with re-radiation)

Box-wing model

Earth radiation

Albedo and Infra-red applied

Albedo and Infra-red applied (Knocke et al. 1988)

Atmospheric density model

msise90

NRLMSISE-00

Radiation pressure coefficient

1 per arc (loosely constrained to 1.0).

Fixed (1.0)

Drag coefficients

10 coefficients per day (loosely constrained to 1.0). 15 coefficients for 32 h.

fixed (1.0)

1/rev empirical

2 sets per day: in along-track and cross-track direction (with sin/cos signals)

1/rev along track and cross track per orbit, constrained (5E-10, 2E-9)

Other empiricals

n/a

Constant empirical accelerations along track at 30 min intervals constrained (1E-9)

GPS measurements

Relativity

applied (IERS 2010)

applied (IGS conventions, Shapiro)

Sampling

10 s

120 s

Observations

iono-free linear combinations of phase and pseudo-range measurements

iono-free linear combinations of phase and pseudo-range (normal points) measurements

Weight

0.8 m (pseudo-range) / 10 mm (carrier-phase)

2 m (pseudo-range) / 20 mm (carrier-phase)

Elevation angle cut-off

7 degrees

10 degrees

Down-weighting law

none

applied for DORIS data

Antenna phase-centre wind-up correction

applied

applied

Antenna phase-centre variation

applied (sen08.atx)

applied (CNES map)

GPS parameters

Receiver clocks

per epoch, every 10 s

per epoch, every 120 s

Receiver ambiguities

estimated (float)

estimated (integer)

GPS orbits

fixed (IGS finals)

fixed (GRG finals)

GPS clocks

fixed (IGS finals)

fixed (GRG finals)

DORIS troposphere

n/a

GPT2/VMF1

DORIS coordinates

n/a

DPOD2014

P.C. Knocke, J.C. Ries, and B.D. Tapley. Earth Radiation Pressure Effects on Satellites. Center for Space Research. The University of Texas at Austin, Austin, Texas. August 15th, 1988.