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WELCOME TO THE IfG FTP PRODUCT SERVER
ftp.tugraz.at/outgoing/ITSG/tvgogo/
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IfG - Kinematic orbit products
18. July 2017
Graz University of Technology
Institute of Geodesy (IfG)
former ITSG
Norbert Zehentner
zehentner@tugraz.at
+43 316 873 6344
or:
Torsten Mayer-Guerr
mayer-guerr@tugraz.at
+43 316 873 6359
Adress: Steyrergasse 30/III
8010 Graz, Austria
Introduction:
-------------
On this ftp server you can find different orbit products produced at the Institute of Geodesy. Access is
granted without any registration and free of charge. All provided products can be used for scientific
research or any other application. Nevertheless, if you publish any results based on our products please
add an acknowledgement and one of the following reference:
Zehentner, N. and Mayer-Gürr, T. (2015). “Precise orbit determination based on raw GPS measurements.”
In: Journal of Geodesy. issn: 0949-7714. doi: 10.1007/s00190-015-0872-7
or
Zehentner, N. (2017). "Kinematic orbit positioning applying the raw observation approach to observe time variable gravity"
PhD Thesis, Graz University of Technology, DOI:10.13140/RG.2.2.33916.33927
Currently products are stored in 17 directories:
folder | time span | description
---------------------|-----------|----------------------------------------------
/orbits/CHAMP | 2002-2010 | kinematic orbit for the Champ satellite
/orbits/CNOFS | 2010-2011 | kinematic orbit for the C/NOFS satellites
/orbits/Cosmic | 2006-2013 | kinematic orbit for the Cosmic satellites
/orbits/GOCE | 2009-2013 | kinematic orbit for the GOCE satellite (contained in TIM release 5 gravity field model)
/orbits/GOCE_ROTI | 2009-2013 | kinematic orbit for the GOCE satellite with ROTI weighting scheme applied (new version containing ROTI info)
/orbits/GRACE | 2002-2016 | kinematic orbit for the Grace satellites
/orbits/Jason1 | 2002-2009 | kinematic orbit for the Jason 1 satellite
/orbits/Jason2 | 2008-2016 | kinematic orbit for the Jason 2 satellite
/orbits/Jason3 | 2016-2016 | kinematic orbit for the Jason 3 satellite
/orbits/Kompsat5 | 2015-2016 | kinematic orbit for the Kompsat 5 satellite
/orbits/MetOpA | 2007-2016 | kinematic orbit for the MetOp-A satellite
/orbits/MetOpB | 2013-2016 | kinematic orbit for the MetOp-B satellite
/orbits/SAC-C | 2002-2013 | kinematic orbit for the SAC-C satellite
/orbits/Sentinel3A | 2016-2016 | kinematic orbit for the Sentinel 3A satellite
/orbits/Swarm | 2013-2016 | kinematic orbit for the Swarm satellites
/orbits/TendemX | 2011-2016 | kinematic orbit for the TanDEM-X satellite
/orbits/TerraSAR-X | 2007-2016 | kinematic orbit for the TerraSAR-X satellite
|-------------------------------------------------------------------------------------------------------------------|
| Processing strategy |
|------------------------------------|------------------------------------------------------------------------------|
|Software: | GROOPS (Gravity Recovery Object Oriented Programming System) developed at |
| | the IfG |
|GNSS system: | GPS |
|Observations: | Code and Phase observations on two frequencies (L1C, L2W, C1W and C2W), |
| | undifferenced, no linear combination |
|Preprocessing: | cycle slip detection based on Melbourne-Wuebbena combination |
|Elevation mask: | 0 degrees |
|Sampling: | varying |
|Observation weights: | varying, azimuth and elevation dependent, GOCE includes ROTI information |
|Satellite antenna offsets: | taken from IGS05 or IGS08 antex files |
|Satellite antenna center variations:| SVN-specific azimuth-nadir dependent values estimated beforehand and |
| | applied in the final solution. parameterized as radial basis functions with |
| | a resolution of ~2.5 degrees. |
|GPS satellite orbit: | Center for orbit determination in Europe final orbit solution with a |
| | sampling of 15 minutes |
|GPS satellite clock correction: | Center for orbit determination in Europe final high-rate solution with a |
| | sampling of 5 or 30 seconds |
|GPS attitude model: | nominal attitude model used, post shadow maneuvers are excluded |
|Phase wind-up: | correction applied |
|Receiver antenna offset: | applied, satellite specific values |
|Receiver antenna center variations: | estimated beforehand for each receiver (azimuth-elevation dependent), |
| | parameterized as spherical harmonics, degree and order is satellite |
| | dependent |
|Differential code bias (DCB): | P1-P2 DCBs applied |
|Troposphere model: | no troposphere at satellite altitude |
|Ionosphere model: | slant total electron content (STEC) estimated in each epoch for each |
| | receiver-transmitter pair |
| | Estimation of STEC includes 1st, 2nd and 3rd order effects |
| | Bending correction applied according: |
| | Hoque MM, Jakowski N (2008) Estimate of higher order ionospheric errors in |
| | GNSS positioning. Radio Sci 43:RS5008. doi:10.1029/2007RS003817 |
| | IGRF11 used for 2nd order effect, STEC taken from previous iteration |
|Background models: | no background models used => kinematic orbit!! |
|------------------------------------|------------------------------------------------------------------------------|
|Reference frames | |
|Time: | GPS time (given as Modified Julian Date in files) |
|Position: | Earth centered Earth fixed (ECEF) IGS05 or IGS08, noted in header lines of |
| | each file |
|------------------------------------|------------------------------------------------------------------------------|
|Least-squares adjustment: | daily solution based on data from 00:00:00 to 23:59:59 |
| | receiver position and receiver clock error for each epoch |
| | STEC for each receiver-transmitter pair in each epoch |
| | phase ambiguities for L1 and L2 for each continous track of a transmitter |
| | |
| | parameters for receiver antenna center variations (spherical harmonics) |
| | for L1/L2 combined, P1 and P2 (not estimted in final solution) |
| | |
| | parameters for transmitter antenna center variations (radial basis |
| | functions) for L1/L2 combined, P1 and P2 (not estimated in final solution) |
| | |
|Ambiguity resolution: | not performed, all products are float solutions |
|-------------------------------------------------------------------------------------------------------------------|
File format description:
------------------------
File naming convention:
The filenames consist of three parts:satellite name, orbit type and date
SatID - type -yyyy-mm-dd.tar.gz
e.g.: GraceA-kinematicOrbit-2010-01-01.tar.gz
All files are compressed.
The format is a simple ASCII format with two header lines giving some additional information on the contained orbit product.
Header lines always start with a #.
First line:
Content length example
-------------------------------------- -------- -----------------------------
Short description of the orbit product variable ITSG - kinematic Orbit GraceA
Geodetic datum variable Geodetic datum: IGS05
Second line:
Column names of the epoch records fixed MJD GPS time [days] x [m] y [m] z [m] xx [m^2] yy [m^2] zz [m^2] xy [m^2] xz [m^2] yz [m^2]
After the header each line represents one epoch. According to the second header line the columns contain the following values:
Column Content Unit
------ -------------- ----
1 GPS time as Modified Julian Date days
2 position x-component m
3 position y-component m
4 position z-component m
5-10 3x3 covariance matrix m^2
-------------------------------------------------------------------------------------
**** The time given as Modified Julian Date represents the measurement epoch. ****
**** POSITIONS ARE NOT INTERPOLATED TO INTEGER SECONDS NOR A CONSTANT SAMPLING!! ****
-------------------------------------------------------------------------------------
The elements of the 3x3 covariance matrix are sorted the following way: xx yy zz xy xz yz
In case of NaN or strange values in one or more of the position or covariance components something went wrong and the epoch should be discarded.
Please send a notification about the satellite and the day in which the anomaly occurs to: zehentner@tugraz.at
Example:
# ITSG - GOCE kinematic Orbit , Geodetic Datum: IGS05
# MJD GPS time [days] x [m] y [m] z [m] xx [m^2] yy [m^2] zz [m^2] xy [m^2] xz [m^2] yz [m^2]
55136.178761574074073 2061306.3577 1937151.9457 5987197.5197 4.67888969e-05 2.73480779e-05 1.24010223e-04 4.25363689e-06 9.39309788e-06 2.40151468e-05
55136.178819444444443 2093805.6053 1951832.6399 5971167.1584 4.39138514e-05 2.71888920e-05 1.21352260e-04 4.91386459e-06 6.50857500e-06 2.46826572e-05
55136.178877314814816 2126244.2665 1966423.2279 5954932.1946 4.10390701e-05 2.70301751e-05 1.18725608e-04 5.57464489e-06 3.63849476e-06 2.53482689e-05
55136.178935185185185 2158621.1854 1980923.2657 5938493.1781 4.10550468e-05 2.70275812e-05 1.18873651e-04 5.56521210e-06 3.59887193e-06 2.53585092e-05
55136.178993055555555 2190935.1802 1995332.3030 5921850.6691 4.10716229e-05 2.70255869e-05 1.19025339e-04 5.55599648e-06 3.55969416e-06 2.53698647e-05
55136.179050925925925 2223185.0957 2009649.8938 5905005.2384 4.10887936e-05 2.70241914e-05 1.19180719e-04 5.54699304e-06 3.52095041e-06 2.53823406e-05
Change log, listing updates on the ftp server:
Date | User | Description
===============================================================
21.04.2015 | NZ | Uploaded orbits for Grace (2002), CHAMP (2002), Jason 1 (2002), SAC-C (2002), MetOp-A (2013)
21.04.2015 | NZ | Uploaded new orbits for 2014 (Grace, Jason 2, MetOp A & B, TanDEM-X and TerraSAR-X) from a complete and consistent reprocessing of all 7 satellites
21.04.2015 | NZ | Added new version of GOCE orbits (folder GOCE_ROTI) New weighting scheme for GPS obs based on ROTI used
28.04.2015 | NZ | Updated Swarm orbits (01.2015-03.2015)
10.06.2015 | NZ | New Swarm orbits uploaded for 07.2014 - 04.2015 (changed weighting scheme of GPS obs -> more realistic covariance information)
10.06.2015 | NZ | Updated Grace time series (01-04.2015)
11.06.2015 | NZ | Added missing months in Grace orbits (October 2012, March, August and September 2013)
20.09.2016 | NZ | Updated Grace orbits from May 2011 until May 2016
20.09.2016 | NZ | Updated complete Swarm time series November 2013 until June 2016
20.09.2016 | NZ | Updated Jason 2 time series from January 2014 until September 2015
18.07.2017 | NZ | Changed folder layout: yearly subfolders removed, subfolders indicate orbit version (v1, v2, ...)
18.07.2017 | NZ | Uploaded new version of orbits for GOCE, GRACE, Jason 2, MetOp A & B, Swarm 1, 2 & 3, TanDEM-X and TerraSAR-X. Time frame for new orbits: May 2011 - December 2016
| Complete and consistent reprocessing of all satellites.
| New satellites added: Jason 3, Sentinel 3A and Kompsat 5.