******************************************************************************** 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 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 10-Dec-2020 (day 20/354, incl. Copernicus POD Regular Service review [RSR] #19). - 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 RSR14) 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 RSR14) 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 - 20/138-20/354: 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. RL02: - Orbits for 06-Apr-2014 (day 14/096) to now (regularly updated). - No days during which Sentinel-1A maneuvers occurred. - Attitude modelling: For days 14/096-22/078 (up to RSR24) the nominal Sentinel-1A attitude law was used, from day 22/079 on the processed star tracker attitude quaternions are 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. - Updated ARP values for all days (see Peter at al., 2020, https://doi.org/10.5194/adgeo-50-87-2020). - GNSS products: CODE repro I20 products (http://ftp.aiub.unibe.ch/REPRO_I20) for days 14/096-18/365, operational CODE products from day 19/001 onwards. - Carrier phase ambiguities fixed to their integer values based on undifferenced ambiguity resolution using CODE's phase bias and clock products. - Reference frames (defined by GNSS products): - 14/096-20/137: IGS14 - 20/138-22/330: IGb14 - 22/331-now : IGS20 - 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 (2022). AIUB Sentinel-1A kinematic orbits, release 02. Published by Astronomical Institute, University of Bern. URL: http://www.aiub.unibe.ch/download/LEO_ORBITS/Sentinel-1A; DOI: 10.48350/165606