Technical description of ignwd05 solution 1) Purpose This weekly times series of coordinates is expressed free-network Projection was not done Transformation was not done The main difference with the d03 series is the gravity field (GGM01C instead of EGM96) and also the fact that now no projection, nor transformation are performed (free-network means really free-network!). 2) Brief description DORIS data have been processed daily using all available satellites (the number of satellite appears in the file) using a free-network approch using the Gipsy-Oasis II software. daily stations positions and EOP have been combined on a weekly basis. 3) Additional comments Information concerning the number of satellites and the number of stations really obvserved on a daily basis has been added in the *.erp file. This is important as EOP are better determined with 3 DORIS satellites (and more in the future) than with only one. JASON/DORIS data have not been used at all Specific information on stations OTTA: Ottawa: several points have been defined for the same antenna using information contained in the DORISMail #0062 jan 4, 1999 AREA: Arequipa: A seond point has been defined after the 2001, June Earthquake. COLA: Colombo: A second point has been defined after November 1994 DIOA: Dyonisos: A second point has been defined after April 1, 1995 SAKA: Sakhalin: A second point has been defined after Oct 5, 1994 (earthquake on Oct 4, 1994) SAKA: Sakhalin: A thhird point has been defined after Dec 26, 1999 KRAB: Krasnoyarsk: A second point has been defined after Nov 1999 SODB: Soccorro Is.: A second point has been defined after Oct 3, 2002 (earthquake on Oct 3, 2002) AMSA: all data have been deleted after Jan 1, 1996 (antenna fall) AMSB: Amsterdam all data have been deleted (antenna fall) SODA: All data have been deleted before Jan 1, 1996 (volcano depletion) ============================================================================= | ANALYSIS CENTRE | | IGN - JPL | | Institut Geographique National | Direction Technique | 2, Avenue Pasteur, BP 68 | 94160 saint-Mande | France | | Jet Propulsion Laboratory | MS 238-600 | 4800 Oak Grove Drive | Pasadena CA 91109 | USA | ----------------------------------------------------------------------------- CONTACT PERSONS | | Pascal Willis (IGN) | E-mail : Pascal.Willis@ign.fr | Phone : +33 (1) 4398 8324 +1 (818) 393 4748 | FAX : +33 (1) 4398 8171 +1 (818) 393 4965 | | Yoaz Bar-Sever (JPL) | E-mail : Yoaz.Bar-Sever@jpl.nasa.gov | Phone : +1 (818) 354 2665 | | ----------------------------------------------------------------------------- SOFTWARE USED | | Gipsy/Oasis II developped at JPL | ----------------------------------------------------------------------------- PREPARATION DATE | | October 2002 - up to now ============================================================================= ----------------------------------------------------------------------------- | MEASUREMENT MODELS | |---------------------------------------------------------------------------| | Data editing | | | | CNES Pre-processing | | | Additional data editing at JPL | | residual > 2 mm/s for all satellites | | | residual > 1.5 mm/s for JASON |---------------------------------------------------------------------------| | Basic measurement| | | | 2 frequencies : 2,03625 GHz (principal channel) and | | | 401.25 MHz | | | | | | entire number of cycles of a beat frequency (first | | | generation instrument on SPOT2, SPOT3, SPOT4, TOPEX/ | | | POSEIDON, ENVISAT satellites) | | | | | | fractional phase differences of a beat frequency | | | (second generation instrument on SPOT5 and JASON1 satel| | | lites) | | | | | | | | |--------------------------------------------------------| | | elevation angle cutoff : as imposed by CNES | | | weighting : 0.5 mm/s | | | 0.35 for JASON | | other : | |---------------------------------------------------------------------------| | Ground antenna | Height dependant on the antenna type | | phase centre cor.| | | | | |---------------------------------------------------------------------------| | Troposphere | LANYI zenith delay model | | |--------------------------------------------------------| | | LANYI mapping function | | | | |---------------------------------------------------------------------------| | Ionosphere | Two frequency model first order model (SOD/CNES) | | | | |---------------------------------------------------------------------------| | Relativity | Applied | | clock effects | | |---------------------------------------------------------------------------| | Plate motions | none (free-network approach) | | | | | | | |---------------------------------------------------------------------------| | Tidal | Solid earth tidal displacement : Wahr model | | displacements |--------------------------------------------------------| | | Pole tide : applied | | |--------------------------------------------------------| | | Ocean loading : applied | |---------------------------------------------------------------------------| | Atmospheric | none | | loading | | |---------------------------------------------------------------------------| | Clocks frequency | onboard frequency bias deduced from the master beacon | | deviation | (a bias per satellite pass) | |---------------------------------------------------------------------------| | Satellite center | applied from CNES preprocessing | | of mass - antenna| | | phase center | | | correction | | |---------------------------------------------------------------------------| | Satellite | For TOPEX/POSEIDON, JASON and ENVISAT | | attitude | SPOT satellites orientation is geocentric | | | | | | | CNES phasecenter corrections were used for all satellites |---------------------------------------------------------------------------| | Receiver-antenna | depends on the channel and the instrument generation | | propagation delay| | | | | |---------------------------------------------------------------------------| ----------------------------------------------------------------------------- | ORBIT MODELS | |---------------------------------------------------------------------------| | Geopotential | GGM01C model up to degree 120 and order 120 | | |--------------------------------------------------------| | | Constants (IERS96 conventions ?) | | | AE = 6378.1363D0 km | | | 1/F = | | | GM = 398600.4415D0 km**3/sec**2 | | | OMEGA = | | | DATE = 01-JAN-1986 | |---------------------------------------------------------------------------| | Third-body | planets : Sun, Moon, Mars, Venus, Jupiter, Saturn and | | | Mercury | | |--------------------------------------------------------| | | ephemeris : DE403 (JPL) | |---------------------------------------------------------------------------| | Air drag | Air density model : DTM-94 | | | Satellite shape from macromodel | | | | |---------------------------------------------------------------------------| | Solar radiation | | | pressure | | | | direct radiation : applied | | |--------------------------------------------------------| | | Earth shadow model includes: penumbra from regularising| | | function | | |--------------------------------------------------------| | | reemitted radiation: albedo applied | | | IR not applied | |---------------------------------------------------------------------------| | satellite | not applied | | thermal thrust | | | | | |---------------------------------------------------------------------------| | Tidal forces | solid earth tides: Wahr model | | |--------------------------------------------------------| | | Ocean tides: | |---------------------------------------------------------------------------| | Atmospheric | none |---------------------------------------------------------------------------| | Relativity | Schwarzschild model | |---------------------------------------------------------------------------| | Numerical | Gipsy/Oasis | | Integration | | | |--------------------------------------------------------| | | integration step: | | |--------------------------------------------------------| | | arc length (orbits): | | | 1 day for all satellites | | | | ----------------------------------------------------------------------------- ----------------------------------------------------------------------------- | ESTIMATED PARAMETERS (APRIORI VALUES & SIGMAS) | |---------------------------------------------------------------------------| | Adjustment | Square-Root Information Filter | | | | |---------------------------------------------------------------------------| | Orbital | | | parameters | | | | Initial position and velocity | | | | | | Solar radiaton pressure : 1 coef/arc | | | | | | Air drag : | | | - Spot and ENVISAT : 1 coef/6 hours | | | - Topex/Poseidon and JASON: 1 coef/ day | | | | | | Empirical accelerations : | | | all satellites | | | 2 coeff cos-sin /orbital period in cross-track direction | | | 2 coeff cos-sin /orbital period in along-track direction | | | | |---------------------------------------------------------------------------| | Stations | | | | Station network coordinates, cartesian | | | system. Apriori constraint (initial solution 10 m) | | | | |---------------------------------------------------------------------------| | Troposphere | | | | Before 2004-JUL-24 (up to week 1280 = 04200) | | 1 zenith path delay bias estimated per satellite pass | | | Apriori values 1.013d0*2.27*exp(-0.116d-03*ht) for Dry | | | 10 cm for Wet | | white noise constraint between passes ( 5 cm per day) | | reset every 30 minutes | | After 2004-JUL-25 (starting with week 1281 = 04207) | | 1 zenith path delay bias estimated per measurement | | | Apriori values 1.013d0*2.27*exp(-0.116d-03*ht) for Dry | | | 10 cm for Wet | | randomwalk estimation ( 5 cm per day = 1.7D-7 km/sqrt(s))) | | reset every 30 minutes |---------------------------------------------------------------------------| | Ionospheric | no parameters estimated | | correction | CNES correction applied | | | | |---------------------------------------------------------------------------| | ERP | x & y pole | | | Current IERS C04 values used as apriori | | | estimated parameters: XPOLE, YPOLE, XPOLERATE, YPOLERATE | | | a priori constraints: X,Y POLE 7.84D-7 !5 m | | | X,Y POLE RATE 2.80D-13 ! 5 masec/day | | | UT1-UTC,UT1-UTCrate | | | UT1-UTC 2.156D-8 ! 0.01 mm | | | UT1-UTC rate 3.470D-8 ! 3 msec/day | |---------------------------------------------------------------------------| | Clocks bias | | | | 1 frequency bias mixed receiver-station per satellite | | | per pass | | | clock drift reset 20:00 for stations and satellites |---------------------------------------------------------------------------| | Other | | | parameters | | ----------------------------------------------------------------------------- ----------------------------------------------------------------------------- | REFERENCE FRAMES | |---------------------------------------------------------------------------| | Inertial | Geocentric; mean equator and equinox of 2000 Jan 1 | | | at 12:00 (J2000.0) | | | | |---------------------------------------------------------------------------| | Terrestrial | ITRF-2000.. reference frame with realization description | | | DORIS station coordinates and velocities in sinex file | | | sinex file has been obtained using a free-network approach | |---------------------------------------------------------------------------| | Interconnection | Precession: IAU 1976 Precession Theory | | |--------------------------------------------------------| | | Nutation: IAU 1980 Nutation Theory | | |--------------------------------------------------------| | | Celestial pole offsets from IERS Bulletin A | | not used | | |--------------------------------------------------------| | | Relationship between UT1 and GMST: | | |--------------------------------------------------------| | | ERP from Bulletin B as a priori | | estimated as parameters | | |--------------------------------------------------------| | | Tidal variations in UT1 and xp: extended sub-daily from Ray | -----------------------------------------------------------------------------