Minimize POD System Baselines and 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-1 mission. System SPOD_SYSTEM_v0.8.4 is taken as a reference for the change log. 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. The table is ordered from the most recent system to the oldest.

Copernicus POD System baselines affecting Sentinel-1
Version Date Change description

SPOD_SYSTEM_v1.8.0

23/09/2020

The system makes use of the GNSS products delivered by the new and backup external GNSS providers (EGPs)

The header of the clocks RINEX files has been updated to show the number of analysis clock references even if this number is equal to zero

SPOD_SYSTEM_v1.7.0

29/07/2020

Change of the S-1 ARP configuration and update of the ANTEX file for S-1 (sen08.atx)

Update GPS ANTEX file (igs14_2114.atx)

SPOD_SYSTEM_v1.6.0

06/05/2020

The system has been updated to include the new models

The NTC products are now ambiguity fixed

Creation of the corresponding chains for being able to upload S-1 NRT/NTC products to the Copernicus Open Access Hub on a daily basis

Corrected an under performance when merging GNSS 15M and 24H input files on the generation of the NRT products

Update GPS ANTEX file (igs14_2101.atx), GPS transponder DB (transp2104300.dat), and GPS satellite DB (satellite2104300.dat)

SPOD_SYSTEM_v1.5.5

14/10/2019

Quaternions products (AUX_PROQUA) can be generated by the system

Alignment of EGP 15M GPS and broadcast clocks products to EGP 24H GPS clocks products during the generation of NRT orbits

Enable the generation of S1 AUX_PREORB products

Update decoder to properly handle the GPS week rollover occurred on 07/04/2019

Update GPS ANTEX (igs14_2062.atx), GPS transponder DB (transp2062400.dat) and GPS satellite DB (satellite2062400.dat)

SPOD_SYSTEM_v1.5.4

06/03/2019

Update GPS satellite and transponder DBs and include new GPS ANTEX according to the launch of the satellite GPS-74

SPOD_SYSTEM_v1.5.3

07/11/2018

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

SPOD_SYSTEM_v1.5.1

04/10/2018

Implemented a satellite re-radiation model

Implemented a fixed solar array model for S1

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

Modifications to correct application of North and East PCO values

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

Corrections on S3PODIPF for redundant receiver:

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

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)

Align RINEX epochs to GPS time instead of IMT for all the orbital products, but the S-3 NRT ones

Enable the uploading of S-1B RESATT products in NRT time

SPOD_SYSTEM_v1.3.9 08/11/2017 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_v1.3.7 11/10/2017 Start processing GNSS RINEX for Copernicus Data Hub, including dissemination mechanisms
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_v1.3.5 27/07/2017 Include option to apply Differential Code Biases when using observations different than P1 and P2
SPOD_SYSTEM_v1.3.4 19/06/2017 Generation and distribution of daily operational RINEX
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_v1.3.1 27/03/2017 Update header for ITRF14 realization in sp3 orbits generation
SPOD_SYSTEM_v1.3.0 16/02/2017 Fix a bug in the computation of the Mean Local Solar Time, responsible for occasional peaks of ~100 min.
Deploy a new GPS ANTEX (igs14_1935.atx)
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 new ANTEX with S-1B information computed using 84 days of residuals
SPOD_SYSTEM_v1.1.0 20/10/2016 Deploy new IPF to decode Sentinel-1 quaternions from SAR Annotation files
Add CMC handling in sp3 orbit generation
Correct expression of the solar radiation pressure partial derivative in the Box Wing Model
SPOD_SYSTEM_v1.0.10 06/09/2016 Update rsgaConv.bin to make it more robust against missing info in Solar Activity File
SPOD_SYSTEM_v1.0.9 27/06/2016 Deploy new ANTEX with S-1B information
SPOD_SYSTEM_v1.0.8 30/05/2016 Solve issue causing occasional incorrect Orbit Number in EOF NRT products
Sentinel-1B launch (22/04/2016)
SPOD_SYSTEM_v1.0.0 18/02/2016 Updated GPS DBs and GPS ANTEX (igs08.atx)
SPOD_SYSTEM_v0.10.0 25/01/2016 Update Box Wing Model for S-1A
SPOD_SYSTEM_v0.9.6 14/12/2015 Update S3PODIPF (GPS L0 decoder) to improve accuracy of pseudo-ranges and avoid usage of GPS Ephemeris
SPOD_SYSTEM_v0.9.5 06/10/2015 Deploy updated ANTEX for S1A GPS redundant receiver
SPOD_SYSTEM_v0.9.4 25/09/2015 Deploy new ANTEX file with information about S-1A nominal and redundant receiver
SPOD_SYSTEM_v0.9.2 14/07/2015 Change NTC determination arc from 72h to 48h
SPOD_SYSTEM_v0.9.1 24/06/2015 Change RMS pseudo-range threshold to 1.0 m and adapt QC Reports threshold
Add option to interpolate attitude file for attitude products generation
SPOD_SYSTEM_v0.8.9 27/02/2015 Correct issues in the generation of S-1A attitude product
SPOD_SYSTEM_v0.8.8 27/01/2015 New WRMS and editing sigma set to 5.0 instead of 3.0
Write RESATT in EO CFI frame
SPOD_SYSTEM_v0.8.7 08/01/2015 Change the IERS standards from IERS2003 to IERS2010
Usage of the gravity field model EIGEN6S instead of the GRACE05
Usage of the ocean tide model EOT11a instead of FES2004
SPOD_SYSTEM_v0.8.6 18/11/2014 Stop upload of S1 RESATT products to FTP
Use MPL_PREORB to obtain orbit number for S-1 NTC and NRT products
SPOD_SYSTEM_v0.8.5 29/09/2014 Remove an interval around manoeuvres in QC Reports to avoid spikes in comparisons
Use last 5 available EGP 24H products instead of only one to improve RESORB products accuracy

 

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

 

Copernicus POD System models and settings affecting Sentinel-1
Analysis Centre
 

Name

CPOD SERVICE

Software

Name and version

NAPEOS

Arc cut

Arc lengths

32 h

Handle of Manoeuvers

Manoeuvres are calibrated in the POD process

Handle of Data gaps

Yes

Reference System

Polar motion and UT1

IERS finals2000A.data

Pole model

IERS 2010 Conventions

Precession/Nutation

IERS 2010 Conventions

Satellite Reference

Mass and centre of gravity

Variable with input from FOS

Attitude Model

Quaternions

GPS antenna reference point (X,Y,Z)

Sentinel-1 properties for GPS POD

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

Sentinel-1 properties for GPS POD

Gravity

Gravity field (static)

EIGEN.GRGS.RL04 TVG (120x120)

Gravity field (time varying)

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

Solid Earth tides

Applied (IERS 2010)

Ocean tides

FES2014 (100x100, 142 tidal constituents)

Atmospheric gravity

GFZ AOD L1B RL06 (100x100)

Atmospheric tides

GFZ AOD L1B RL06 (100x100)

Earth pole tide

IERS 2010

Ocean pole tide

IERS 2010

Third bodies

Sun, Moon, Planets DE405

Surface forces and empiricals

Radiation Pressure model

Box-wing model (with re-radiation)

Earth radiation

Albedo and Infra-red applied

Atmospheric density model

msise00

Radiation pressure coefficient

1 per arc (loosely constrained to 1.0)

Drag coefficients

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

1/rev empirical

2 sets per day: in along-track and cross-track direction (with sin/cos signals)
3 sets per 32 h: in along-track and cross-track direction (with sin/cos signals)

Other empiricals

n/a

GPS measurements

Relativity

Applied (IERS 2010)

Sampling

10 s

Observations

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

Weight

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

Elevation angle cut-off

7 degrees

Down-weighting law

None

Antenna phase-centre wind-up correction

Applied

Antenna phase-centre variation

Applied (sen08.atx)

GPS parameters

Receiver clocks

Per epoch, every 10 s

Receiver ambiguities

Estimated (fixed)

GPS orbits

Fixed (CODE finals)

GPS clocks

Fixed (CODE finals)

GPS satellite biases

CODE finals

DORIS troposphere

n/a

DORIS coordinates

n/a