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README
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University of Bern
Astronomical Institute (AIUB)
Daniel Arnold
daniel.arnold@aiub.unibe.ch
+41 31 631 3802
or:
Adrian Jaeggi
adrian.jaeggi@aiub.unibe.ch
+41 31 631 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 (IGS08) |
| 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 |
|------------------------------------------------------------------------------|
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.
RL02: Orbits for 25-Nov-2013 to present (regularly uploaded). 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-now : 0305
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