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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 Sentinel-1A 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 |
| | for clock synchronization and wide-lane|
| | ambiguity resolution |
| Sampling | 10s |
| Elevation angle cutoff | 0 deg |
| Antenna offset (w.r.t CoM) | Time-dependent values (see below) |
| 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 |
| Relativistic corrections | 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 Sentinel-1A satellite
given in daily batches.
File naming convention: S1A_RL_.KIN
: Release number (see below)
: 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 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: LEO name (SE1A)
Column 2: modified SVN number (L70)
Column 3: GPS antenna used for POD
(main antenna: POD1, redundant antenna: POD2)
Column 4: GPS week
Column 5: GPS second within the given GPS week [s]
Column 6: position x-component (Earth-centered Earth-fixed) [m]
Column 7: position y-component (Earth-centered Earth-fixed) [m]
Column 8: position z-component (Earth-centered Earth-fixed) [m]
Column 9: quality flag (possible values are K, X, S and G, see below)
Column 10: xx-element of 3x3 epoch-wise cofactor matrix
Column 11: yy-element of 3x3 epoch-wise cofactor matrix
Column 12: zz-element of 3x3 epoch-wise cofactor matrix
Column 13: xy-element of 3x3 epoch-wise cofactor matrix
Column 14: xz-element of 3x3 epoch-wise cofactor matrix
Column 15: 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 (if screening applied)
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.
Note on cofactors:
Columns 10-15 contain the epoch-wise 3x3 cofactor matrix. In order to compute
the epoch-wise covariance matrix for the positions these cofactors need to
be multiplied by the square of the a posteri RMS value found in line 4 of the
header.
Releases
========
RL01: - Orbits for 06-Apr-2014 (day 14/096) to now (regularly updated).
- No days during which Sentinel-1A maneuvers occurred.
- Attitude modelled according to nominal Sentinel-1A attitude law
(no star tracker quaternions used).
- Based on data of redundant GPS antenna for days 15/209-15/214 and
15/225-15/257, nominal GPS antenna for all other days.
- Up to day 19/026 the original Sentinel-1A GPS antenna reference point
(ARP) values were used. From day 19/027 (start of Copernicus POD
Regular Service Review #14) on the updated ARP values were used.
- Up to day 19/026 carrier phase ambiguities are estimated as float
values. From day 19/027 (start of Copernicus POD Regular Service
Review #14) on ambiguities are fixed to their integer values based
on undifferenced ambiguity resolution using CODE's phase bias and
clock products.
- Reference frames (defined by GNSS products):
- 14/096-17/028: IGb08
- 17/029-20/137: IGS14
- 20/138-now : IGb14
- Kinematic orbit positions were not screened for outliers.
- When using these Sentinel-1A kinematic orbits, please cite them using
the following reference:
Arnold, Daniel; Jäggi, Adrian (2020). AIUB Sentinel-1A kinematic orbits,
release 01. Published by Astronomical Institute, University of Bern.
URL: http://www.aiub.unibe.ch/download/LEO_ORBITS/Sentinel-1A;
DOI: 10.7892/boris.145822.