============================================================================= INTERNATIONAL LASER RANGING SERVICE YOUR ORGANIZATION NAME AND ACRONYM HERE Analysis Strategy Summary ============================================================================= |ANALYSIS CENTRE | Deutsches Geodaetisches Forschungsinstitut, DGFI | | | Alfons-Goppel-Str. 11 | | | 80539 Muenchen | | | Germany | |---------------------------------------------------------------------------- |CONTACT PERSONS | Horst Mueller, (mueller@dgfi.badw.de, | | | phone: +4989230311277, fax: +4989230311240) | |---------------------------------------------------------------------------- |SOFTWARE USED | DOGS version 5.00 | |---------------------------------------------------------------------------- |ILRS PRODUCTS | Daily Bias reports for Lageos-1 and Lageos-2 | | | (Etalon-1/2, Starlette and Ajisai in preparation) | | | Weekly SP3C orbit for Lageos-1 and Lageos-2 | | | Daily EOP's and station coordinates, on a weekly basis | |---------------------------------------------------------------------------- |PREPARATION DATE | 1980, as ILRS/AC since | |===========================================================================| ----------------------------------------------------------------------------- | MEASUREMENT MODELS | |---------------------------------------------------------------------------| | Satellites used | Lageos-1, Lageos-2, Etalon-1, Etalon-2 | |---------------------------------------------------------------------------| | Basic measurement| Satellite Laser Ranging (SLR): round-trip travel time | | |--------------------------------------------------------| | | speed of light : 299792458 m/s | | | wavelength : 532.0, 423.0, 847.0 & 694.3 nm| | | elevation angle cutoff : 0 degrees | | | weighting : 1.0 m per AWG2000 | | | range biases : est/d for non-core stations | | | time biases : not modeled/estimated | | | tropospheric biases : not modeled/estimated | |---------------------------------------------------------------------------| | Data editing | 3.0 sigma editing | |---------------------------------------------------------------------------| | Troposphere | Mendes-Pavlis zenith delay model | | |--------------------------------------------------------| | | Mendes-Pavlis mapping function | |---------------------------------------------------------------------------| | Ionosphere | not modeled/estimated | |---------------------------------------------------------------------------| | Relativity | scale: LET (TT time scale) | | | effects: light time corrections | |---------------------------------------------------------------------------| | Satellite center | Lageos-1 0.251 m, Lageos-2 0.251 m | | of mass | Etalon-1 0.558 m, Etalon-2 0.558 m | | | Starlette .075 m, Ajisai 1.010 m | |---------------------------------------------------------------------------| | Other | | |---------------------------------------------------------------------------| ----------------------------------------------------------------------------- | ORBIT MODELS | |---------------------------------------------------------------------------| | Geopotential | GGM02S (static terms through degree and order 30) | | | (C(2,0), C(2,1) and S(2,1) time dependent) | | |--------------------------------------------------------| | | Constants | | | AE = 6378.1363 km | | | 1/F = 298.2564 | | | GM = 398600.4415 km3/s2 | |---------------------------------------------------------------------------| | Third-body | planets: | | | Mercury, Venus, Earth Moon, Mars, Jupiter, Saturn, | | |--------------------------------------------------------| | | ephemeris: JPL DE405 | |---------------------------------------------------------------------------| | Solar radiation | IERS Conventions 2003 | | pressure | | | | direct radiation : applied | | | albedo radiation : applied | | | earth thermal radiation : not applied | | |--------------------------------------------------------| | | Earth shadow model includes: penumbra | | |--------------------------------------------------------| | | reemitted radiation: not applied | |---------------------------------------------------------------------------| | satellite | modeled | | thermal thrust | all satellites: estimation of empirical ( once-per-rev)| | | along-track and cross-track accelerations | | | (1 set per weekly solution) | | | | |---------------------------------------------------------------------------| | Tidal forces | solid earth tides: IERS 2003 Conventions model | | |--------------------------------------------------------| | | Ocean tides: Ray GOT99.2b | |---------------------------------------------------------------------------| | Atmospheric | not modeled/estimated | | gravitational | | | attraction | | |---------------------------------------------------------------------------| | Dynamic | applied, IERS Conventions 2003 | | polar motion | | |---------------------------------------------------------------------------| | Relativity | point-mass accelerations, Lense-Thirring effect, | | | coriolis force | |---------------------------------------------------------------------------| | Numerical | Cowell 6th order predictor-corrector | | integration |--------------------------------------------------------| | | integration step: L1: 60 s, L2: 60 s, E1 & E2: 120 s | | | St: 30 s, Aj: 60 s, | | |--------------------------------------------------------| | | arc length (orbits): 7 days | ----------------------------------------------------------------------------- ----------------------------------------------------------------------------- | ESTIMATED PARAMETERS (APRIORI VALUES & SIGMAS) | |---------------------------------------------------------------------------| | Adjustment | weighted least-squares adjustment | |---------------------------------------------------------------------------| | Orbital | Initial position and velocity: | | parameters | estimated for each satellite (unconstrained) | | | Solar radiaton pressure 3 values per arc adjusted | | | Empirical accelerations 3 values per arc adjusted | |---------------------------------------------------------------------------| | Stations | definition: SLR monument (eccentricities subtracted), | | | at mean epoch of each arc | | | resp. intersection of axes (if no ecc. av.)| | | a priori values: SLRF2005 | | | a priori standard deviation: 0.001 m | | | for new stations (not included in SLRF2005) | | | a priori standard deviation: 0.05 m | |---------------------------------------------------------------------------| | Troposphere | not estimated | |---------------------------------------------------------------------------| | EOP | definition: x-pole, y-pole, UT1-UTC and LOD | | | epoch: at noon of each day | | | frequency: daily | | | a priori values: IERS 05 C04 and USNO Bul. A | | | a priori standard deviation: 60 masec, 4 sec | |---------------------------------------------------------------------------| | Range biases | for all stations | | | a priori value: 0 m | | | a priori standard deviation: free | |---------------------------------------------------------------------------| | Constraints | loose constraints 1 m for EOP | |---------------------------------------------------------------------------| ----------------------------------------------------------------------------- | REFERENCE FRAMES | |---------------------------------------------------------------------------| | Inertial | J2000.0 | |---------------------------------------------------------------------------| | Terrestrial | SLRF2005 (a priori station coordinates) | | | SLRF2005 (station velocities) | | | NUVEL-1A (2nd source for station velocities) | | | tidal uplift: IERS 2003 Conventions | | | ocean loading: GOT00.2 | | | atmospheric pressure loading: not modeled/estimated | | | geocenter motion: not explicitly modeled/estimated | | | geocenter tidal frequencies: applied | | | pole tide: IERS 2003 Conventions | | | origin: C(1,0) = C(1,1) = S(1,1) = 0 | | | orientation: fixed to SLRF2005 | |---------------------------------------------------------------------------| | Interconnection | Precession: IERS Conventions 2003 | | |--------------------------------------------------------| | | Nutation: IAU 2000 | | |--------------------------------------------------------| | | Celestial pole: IERS 2003 Conventions | | |--------------------------------------------------------| | | Relationship between UT1 and GMST: UT1-UTC estimated | | |--------------------------------------------------------| | | Earth Orientation Parameters: estimated | | | (IERS 05 C04 p. USNO Bul. A priori) | | |--------------------------------------------------------| | | Tidal variations in UT1 and PM: IERS 2003 Conventions | ----------------------------------------------------------------------------- ----------------------------------------------------------------------------- | OTHER INFORMATION | |---------------------------------------------------------------------------| | Processing | Simultaneous solution for orbit, arc dependent | | | parameters, EOP's, stations and range biases | | | in an iterative process | |---------------------------------------------------------------------------|