******************************************************************************** README ******************************************************************************** University of Bern Astronomical Institute (AIUB) Daniel Arnold daniel.arnold@aiub.unibe.ch +41 31 684 3802 or: Adrian Jaeggi adrian.jaeggi@aiub.unibe.ch +41 31 684 8596 Address: Sidlerstrasse 5 3012 Bern, Switzerland Short notice on AIUB Swarm kinematic orbits: |------------------------------------------------------------------------------| | Processing strategy | |-------------------------------------|----------------------------------------| | Software | Bernese GNSS Software v5.3 | | GNSS system | GPS | | Arc length | 1.0 days | | Reference system | | | Time | GPS time (GPST) | | Position | Earth-centered Earth-fixed (see below) | | Polar motion and UT1 | CODE final products | | Pole model | IERS 2010 conventions | | Precession/Nutation | IERS 2010 conventions | | GPS orbits | CODE final products | | GPS clocks | CODE final 5s clocks | | GPS measurements | | | Observations | Ionosphere-free linear combination of | | | phase measurements, pseudo-range used | | | only for clock synchronization | | Sampling | 10s up to 15-Jul-2014 | | | (Swarm-A 06:42:59 GPST, | | | Swarm-B 06:06:46 GPST, | | | Swarm-C 08:15:59 GPST), 1s afterwards | | Elevation angle cutoff | 0 deg | | Antenna offset | LEO-specific and time-dependent values | | GPS antenna phase center var. | Determined for each antenna from | | | stacking of carrier phase residuals of | | | reduced-dynamic orbit determination | | Observation weighting | Constant | | Antenna phase-center wind-up | Correction applied | | Solution strategy | Daily least-squares solution based on | | | data from 00:00:00 to 23:59:59 | | Estimated parameters | | | Receiver position | Every epoch | | Receiver clock correction | Every epoch | | Carrier phase ambiguities | Float or fixed (see below) | |------------------------------------------------------------------------------| General remarks =============== This product contains kinematic orbit positions of the Swarm satellites given in daily batches per single satellite. File naming convention: SWM.KIN : A, B or C (specifying the corresponding Swarm satellite) : year (last two digits) : day of year Format description ================== File header: Line 1: description of orbit including release number and orbit generation date and time Line 2: dummy line Line 3: information about geodetic datum and date & time of first epoch (GPS time) Line 4: a posteriori standard deviation of L1/L2 GPS carrier phase res. [m] Line 5: description of columns Line 6: dummy line Data records: After the header each line represents one epoch. The columns contain the following quantities: Column 1: internal AIUB satellite name (Swarm-A: SWMA, Swarm-B: SWMB, Swarm-C: SWMC) Column 2: modified SVN number (Swarm-A: L47, Swarm-B: L48, Swarm-C: L49) Column 3: GPS week Column 4: GPS second within the given GPS week [s] Column 5: position x-component [m] Column 6: position y-component [m] Column 7: position z-component [m] Column 8: quality flag (possible values are K, X, S and G, see below) Column 9: xx-element of 3x3 epoch-wise cofactor matrix Column 10: yy-element of 3x3 epoch-wise cofactor matrix Column 11: zz-element of 3x3 epoch-wise cofactor matrix Column 12: xy-element of 3x3 epoch-wise cofactor matrix Column 13: xz-element of 3x3 epoch-wise cofactor matrix Column 14: yz-element of 3x3 epoch-wise cofactor matrix Meaning of quality flags: K: kinematic orbit position could be properly determined X: kinematic orbit position could not be determined (less than 4 satellites) S: kinematic orbit position could be determined, but less than 5 satellites were available G: kinematic orbit position has been flagged during internal AIUB orbit screening Please note: - Users who would like to use all available epochs or do their own orbit screening should use all epochs marked with the flags K or G. - Users who would like to rely on the internal AIUB orbit screening should use only epochs marked with flag K. - It is recommended not to use epochs denoted with the flag S. Releases ======== RL01: Orbits for 25-Nov-2013 to 27-May-2015. The orbits were computed from the following data sets (baseline, file counter): 13/329-15/001: 0302 15/002-15/017: 0303 15/018-15/051: 0302 15/052-15/088: 0303 15/089-15/147: 0302 Notice that the orbits for Swarm-A and Swarm-B after 06-May-2015 are not of optimal quality as they are based on PCVs not taking into account the increased FOV after 06-May-2015. Carrier phase ambiguities not resolved to their integer values. Reference frame (defined by GNSS products): IGb08 When using these Swarm kinematic orbits, please cite them using the following reference: Arnold, Daniel; Jäggi, Adrian (2021). AIUB Swarm kinematic orbits, release 01. Published by Astronomical Institute, University of Bern. URL: http://www.aiub.unibe.ch/download/LEO_ORBITS/SWARM DOI: 10.48350/158375 RL02: Orbits for 25-Nov-2013 to 31-Dec-2016. Correct PCVs are used. Data sets used as in RL01 and in addition: 15/089-15/198: 0302 15/199-16/101: 0304 16/102-16/366: 0305 Carrier phase ambiguities not resolved to their integer values. Reference frame (defined by GNSS products): IGb08 When using these Swarm kinematic orbits, please cite them using the following reference: Arnold, Daniel; Jäggi, Adrian (2021). AIUB Swarm kinematic orbits, release 02. Published by Astronomical Institute, University of Bern. URL: http://www.aiub.unibe.ch/download/LEO_ORBITS/SWARM DOI: 10.48350/158374 RL03: Orbits for 25-Nov-2013 to now (regularly updated). These kinematic orbits are based on GPS data which have been screened to mitigate the ionosphere-induced artifacts along the geomagnetic equator. For that purpose all GPS observations with an absolute value of the first time derivative of the geometry-free linear combination of L1 and L2 exceeding 2cm/s have been omitted. Data sets used as in RL02 and in addition: 16/102-18/246: 0305 18/247-20/037: 0401 20/038-22/257: 0402 22/258-now : 0502 Carrier phase ambiguities: 13/329-20/025: Float 20/026-now : Fixed Reference frames (defined by GNSS products): - 13/329-17/028: IGb08 - 17/029-20/137: IGS14 - 20/138-22/330: IGb14 - 22/331-now : IGS20 When using these Swarm kinematic orbits, please cite them using the following reference: Arnold, Daniel; Jäggi, Adrian (2021). AIUB Swarm kinematic orbits, release 03. Published by Astronomical Institute, University of Bern. URL: http://www.aiub.unibe.ch/download/LEO_ORBITS/SWARM DOI: DOI: 10.48350/158373 Reference ========= Jaeggi A et al. (2015): Swarm kinematic orbits and gravity fields from 18 months of GPS data. Adv Space Res 57 (2016) 218-233, doi: 10.1016/j.asr.2015.10.035