============================================================================= INTERNATIONAL GNSS SERVICE CODE Analysis Strategy Summary for IGS repro I20 ============================================================================= | Analysis Center | Center for Orbit Determination in Europe (CODE) | | | Astronomical Institute | | | University of Bern | | | Sidlerstrasse 5 | | | CH-3012 Bern | | | Switzerland | | | E-mail: code(at)aiub.unibe.ch (CODE AC Team) | | | Phone: +41-31-631-8591 | | | Archive: ftp://ftp.aiub.unibe.ch/REPRO_2020/ | | | http://www.aiub.unibe.ch/download/REPRO_I20 | | | Web: http://www.aiub.unibe.ch (CODE at AIUB) | | | http://www.bernese.unibe.ch (Bernese SW) | |---------------------------------------------------------------------------| | Contact People | Please us the general contact address | | | E-mail: code (at) aiub.unibe.ch | | | | | | Arturo Villiger | | | E-mail: arturo.villiger(at)aiub.unibe.ch | | | Phone: +41-31-631-8506 (8591) | | | Rolf Dach | | | E-mail: rolf.dach(at)aiub.unibe.ch | | | Phone: +41-31-631-8593 (8591) | |---------------------------------------------------------------------------| | Software Used | Bernese GNSS Software Version 5.3, developed at AIUB | |---------------------------------------------------------------------------| | GNSS system(s) | GPS, GLONASS, Galileo | |---------------------------------------------------------------------------| | List of CODE's | ftp://ftp.aiub.unibe.ch/AIUB_AFTP.TXT | | analysis products | http://www.aiub.unibe.ch/download/AIUB_AFTP.TXT | | | | | Final Products | Product reference: | | generated for | Selmke, I., R. Dach, D. Arnold, L. Prange, S. Schaer, | | GPS week 'wwww' | D. Sidorov, P. Stebler, A. Villiger, A. Jaeggi, | | day of week 'n' | U. Hugentobler (2020). | | (n=0,1,...,6) | CODE repro3 product series for the IGS. Published by | | day of year 'ddd' | Astronomical Institute, University of Bern. | | year 'yy' | URL: http://www.aiub.unibe.ch/download/REPRO_2020; | | | DOI: 10.7892/boris.135946. | | | | | | Files generated from three-day long-arc solutions: | | Ephemeris | CORyyddd.EPH.gz | | | GNSS ephemeris/clock data in 7 daily files at 5-min | | | intervals in SP3d format, including accuracy codes | | | computed from a long-arc analysis | | ERP | CORyyddd.ERP.gz | | | GNSS ERP (pole, UT1-UTC) solution in IGS ERP format | | Clocks, 30s | CODyyddd.CLK.gz | | | GNSS satellite and receiver clock corrections at | | | 30-sec intervals referring to the COD-orbits from | | | the long-arc analysis in clock RINEX 2.00 format | | Clocks, 5s | CODyyddd_5s.CLK.gz | | | GNSS satellite and receiver clock corrections at | | | 5-sec intervals referring to the COD-orbits from | | | the long-arc analysis in clock RINEX 2.00 format | | Code & Phase bias | CODyyddd.BIA.gz | | | CODE daily code and phase bias solution | | | corresponding to the above mentioned clock products | | | in BIAS-SINEX 1.00 format | | Code & Phase bias | CODyyddd.OSB.gz | | | CODE daily code and phase bias solution | | | corresponding to the above mentioned clock products | | | in Bernese OSB format | | | | | | Remarks: | | | | | | EPH: Orbit positions correspond to the estimates | | | for the middle day of a 3-day in case of a | | | long-arc analysis. | | | CLK: Satellite clock corrections are consistent | | | with carrier phase as well as C1W/C2W (GPS), | | | C1P/C2P (GLONASS) and C1C/C5Q (Galileo) | | | pseudorange measurements. | | | CODE code bias values are considered to | | | correct receiver data with other measurement | | | types. | | | BIA: The usage of the phase biases for ambiguity | | | resolution in PPP applications is explained | | | in ftp://ftp.aiub.unibe.ch/CODE/IAR_README.TXT | | | | | | | | Specialties in | - CODE has been generating its products from a | | CODE's analysis | rigorous combination of GPS, GLONASS, and Galileo | | | observations. In this way, best possible | | | consistency of the orbit products is guaranteed. | | | - Uninterrupted POD for all transmitting GNSS | | | satellites, specifically for: | | | . brand new satellites | | | . satellites without any broadcast orbit information| | | . satellites marked unhealthy/unusable | | | . poorly observed (GLONASS) satellites | | | . (GPS) satellites being repositioned | | | . Galileo satellites at a very early stage of the | | | constellation and limited tracking network | | | coverage | | | - Elevation mask angle of 3 degrees used. | | | - Sophisticated ambiguity resolution scheme for GPS | | | and Galileo, but also GLONASS ambiguity resolution | | | (with restrictions, specifically for baselines | | | longer than 200 km), self-calibrating for GLONASS. | | | - Ambiguity verification scheme: resolved ambiguities | | | are checked in terms of compatibility, also in order| | | to detect unexpected quarter-cycle issues. | | | - GPS quarter-cycle phase bias issue: potentially | | | affected GPS ambiguities are banned from ambiguity | | | resolution. | | | - Provision of phase biases for GPS and Galileo | | | consistent to the CODE orbit and clock products | | | allowing for ambiguity resolution in a user's PPP | | | (see ftp://ftp.aiub.unibe.ch/CODE/IAR_README.TXT) | | | - Continuous parametrization, particularly for EOP, | | | troposphere ZPD and horizontal gradient parameters, | | | ionosphere parameters, allowing for connection of | | | the parameters at day boundaries. | | | - For the three-day long-arc final solution the | | | continuity is only realized via constraints keeping | | | the realted parameters independent, in particular | | | SINEX file generation (compatibility to one-day | | | solutions from other analysis centers). | | | - IGS fiducial sites are automatically verified for | | | consistent datum definition. | | | - Generation of high-rate (5-sec) clock products | | | (internally even with a second midnight epoch | | | allowing for PPP-solutions across midnight). | | | - Generation of high-rate (1-hour) EOP results | | | (internally). | | | - Setup of GNSS satellite antenna PCV parameters | | | specific to each individual GPS, GLONASS and Galileo| | | satellite; corresponding patterns are not only | | | available for the ionosphere-free linear | | | combination but also for the geometry-free linear | | | combination. | | | - 3 terms of higher-order ionosphere (HOI) effects are| | | taken into account (based on CODE GIM & IGRF13SYN). | | | Scaling factor for 2nd and 3rd order HOI as well as | | | for ray bending for validation purposes and to | | | switch the parameter on or off | | | - Non-tidal loading correction (Dill & Dobslaw, 2013) | | | at observation level with scaling factors to obtain | | | solutions without applying such corrections | | | - Provision of GNSS geocenter coordinates in SINEX. | | | | | Computer platform | Calculations were performed on | | | Serial part of LRZ Linux Cluster and | | | Calculations were performed on UBELIX | | | UBELIX (http://www.id.unibe.ch/hpc) | | | the HPC cluster at the University of Bern | | | | |---------------------------------------------------------------------------| | Preparation Date | 07-Oct-2020 | ============================================================================= ============================================================================= | MEASUREMENT MODELS | |---------------------------------------------------------------------------| | Preprocessing | Phase preprocessing in a baseline by baseline mode | | | using triple-differences. In most cases, cycle slips | | | are fixed looking simultaneously at different linear | | | combinations of L1 and L2. If a cycle slip cannot be | | | fixed reliably, bad data points are removed or new | | | ambiguities are set up. In addition, a data screening | | | step on the basis of weighted postfit residuals is | | | performed. Outliers are removed. | |---------------------------------------------------------------------------| | Basic Observables| GPS/GLONASS/Galileo carrier phase; code only used for | | | receiver clock synchronization and MW ambiguity | | | resolution | | | Priorities for observation selection: | | | G L1 L1P L1C L1X | | | G L2 L2P L2C L2D L2W L2X | | | G C1 C1P C1C C1X | | | G C2 C2P C2C C2D C2W C2X | | | R L1 L1P L1C L1X | | | R L2 L2P L2C L2X | | | R C1 C1P C1C C1X | | | R C2 C2P C2C C2X | | | E L1 L1C L1X | | | E L2 L5Q L5I L5X | | | E C1 C1C C1X | | | E C2 C5Q C5I C5X | | |--------------------------------------------------------| | | Elevation angle cutoff : 3 degrees | | | Sampling rate : 3 minutes | | | Weighting : 6 mm for double-differenced | | | ionosphere-free phase | | | observations at zenith; | | | elevation-dependent weighting| | | function 1/cos(z)**2 | |---------------------------------------------------------------------------| | Modeled | Double differences, ionosphere-free linear combination | | observables | of GPS/GLONASS: L1 and L2; | |---------------------------------------------------------------------------| | Satellite antenna| SV-specific z-offsets & block-specific x- & y-offsets | | -center of mass | from IGS using file igs14.atx | | offsets | | |---------------------------------------------------------------------------| | Satellite antenna| PVs applied from file igs14.atx; | | phase variantions| GPS/GLO: block-specific nadir angle-dependent | | | PVs based on igs14.atx | |---------------------------------------------------------------------------| | Satellite clock | 2nd order relativistic correction for non-zero | | corrections | orbit ellipticity (-2*R*V/c) applied | | | NOTE: Other dynamical relativistic effects under | | | Orbit Models | |---------------------------------------------------------------------------| | GPS attitude | Nominal (yaw-steering) attitude implemented. | | model | | |---------------------------------------------------------------------------| | RHC phase | Phase polarization effects applied (Wu et al., 1993) | | rotation corr. | | |---------------------------------------------------------------------------| | Ground antenna | - "absolute" elevation- & azimuth-dependent PCVs & | | phase center | offsets for each GNSS from file igs14.atx applied | | offsets & | - observations are omitted if no system-specific | | variations | calibration was available | |---------------------------------------------------------------------------| | Antenna radome | Calibration applied if given in file igs14.atx; | | calibrations | otherwise radome effect neglected (radome => NONE) | | | - stations where antenna and radome calibrations have | | | been selected to the extent possible | |---------------------------------------------------------------------------| | Marker -> antenna| dN, dE, dU eccentricities from site logs applied to | | ARP eccentricity | compute station coordinates | |---------------------------------------------------------------------------| | Troposphere | ECMWF-based hydrostatic delay mapped with hydrostatic | | a priori model | VMF1. Coefficients from 6-hourly global grids. | | | | | | Gradient model: none | |---------------------------------------------------------------------------| | Ionosphere | 1st order effect: eliminated by forming the | | | ionosphere-free linear combination. | | |--------------------------------------------------------| | | 2nd order effect: applied, IGRF13 implementation, TEC | | | from CODE global ionosphere model | | |--------------------------------------------------------| | | 3rd order effect: applied, TEC from CODE global | | | ionosphere model | | |--------------------------------------------------------| | | Other effects: ray benigsmail@lists.igs.orgding applied, TEC from CODE | | | global ionosphere model | | | | | | GNSS-derived global ionosphere map | | | information is used to support | | | ambiguity resolution when using the | | | QIF strategy. | |---------------------------------------------------------------------------| | Tidal | Solid Earth tide : complete model from IERS | | displacements | Conventions 2010 | | | | | | Step 1: in-phase: degree 2 and 3 | | | Nominal h02 and l02 : 0.6078, 0.0847 (anela.)| | | Nominal h22 and l22 :-0.0006, 0.0002 | | | Nominal h3 and l3 : 0.292 , 0.015 | | | | | | out-of-phase: degree 2 only semi- and diurnal | | | diurnal: nominal hI, lI :-0.0025,-0.0007 | | | semi-di: nominal hI, lI :-0.0022,-0.0007 | | | | | | latitude dependence | | | diurnal: nominal l1 : 0.0012 | | | semi-di: nominal l1 : 0.0024 | | | | | | Step 2: in-phase: degree 2, diurnal | | | in-phase and out-of-phase: long-period tides | | |--------------------------------------------------------| | | Permanent tide : applied in tide model, | | | NOT included in site coordinates| | |--------------------------------------------------------| | | Solid Earth pole tide: applied (IERS 2010) | | |--------------------------------------------------------| | | Oceanic pole tide : not applied | | |--------------------------------------------------------| | | Ocean tide loading : IERS 2010, site-dependent amps | | | & phases from Bos & Scherneck | | | website for FES2014b tide model | | | NEU site displacements computed | | | using hardisp.f from D. Agnew | | |--------------------------------------------------------| | | Ocean tide geocenter : coeffs. corrected for center of | | | mass motion of whole Earth | | |--------------------------------------------------------| | | Atmospheric tides : None | |---------------------------------------------------------------------------| | Non-tidal | Atmospheric pressure : Non-tidal components from the | | loadings | GFZ atmospheric pressure | | | model with scaling factors set | | | to zero for product generation | | |--------------------------------------------------------| | | Ocean bottom pressure: GFZ ocean pressure model with | | | scaling factors set to zero | | | for product generation | | |--------------------------------------------------------| | | Surface hydrology : GFZ surface hydrology model | | | with scaling factors set to | | | zero for product generation | | |--------------------------------------------------------| | | Other effects : none applied | | |--------------------------------------------------------| | | Remark on product generation | | | All product files are generated | | | without considering the non- | | | tidal pressure loading by | | | forcing the scaling factors to | | | zero. | |---------------------------------------------------------------------------| | Earth orientation| Ocean tidal: diurnal/semidiurnal variations in x,y, & | | variations | UT1 applied according to IERS 2010, Tables| | | 8.2a, 8.2b, 8.3a, 8.3b | | |--------------------------------------------------------| | | Atmosphere tidal: S1, S2, S3 tides not applied | | |--------------------------------------------------------| | | High-frequency nutation: applied according to IERS | | | 2010, Table 5.1a | | |--------------------------------------------------------| | | UT1 libration: applied according to IERS 2010, Table | | | 5.1.b | ============================================================================= ============================================================================= | REFERENCE FRAMES | |---------------------------------------------------------------------------| | Time argument | TDT | | | GPS time as given by observation epochs, which is | | | offset by only a fixed constant (approx.) from TT/TDT | |---------------------------------------------------------------------------| | Inertial | geocentric; mean equator and equinox of 2000 Jan 1 | | frame | at 12:00 (J2000.0) | |---------------------------------------------------------------------------| | Terrestrial | ITRF2014 reference frame realized through a set of | | frame | station coordinates and velocities given in the IGS | | | internal realization IGb14. | | | | | | Datum definition: | | | . 3 no-net translation conditions (only if geocenter | | | is estimated) | | | . 3 no-net rotation conditions | | | . geocenter coordinates constrained nominally to | | | zero values | | | IGb14 fiducial sites are selected as reference, if | | | . horizontal deviation < 10 mm | | | . vertical deviation < 30 mm | |---------------------------------------------------------------------------| | Tracking | Between 50 and 300 stations per day are used. | | network | Station selection is based on long time series, | | | contribution to existing reference frames, | | | co-location with other space-geodetic techniques, | | | GLONASS/Galileo-capability, data availability, receiver| | | antenna calibration availability, and all-in-view | | | tracking support for unhealthy satellites. | |---------------------------------------------------------------------------| | Interconnection | Precession: IAU 2000 Precession Theory | | |--------------------------------------------------------| | (EOP parameter | Nutation: IAU 2000R06 Nutation Theory | | estimation is |--------------------------------------------------------| | below) | A priori EOPs: polar motion & UT1 from IERS C04 series | | | aligned to ITRF2014 | ============================================================================= ============================================================================= | ORBIT MODELS | |---------------------------------------------------------------------------| | Geopotential | EGM2008 model up to degree and order 12 (+C21+S21) | | (static) |--------------------------------------------------------| | | GM = 398600.4415 km**3/sec**2 | | |--------------------------------------------------------| | | AE = 6378.1363 km | |---------------------------------------------------------------------------| | Tidal variations | Solid Earth tides: applied according to IERS 2010 | | in geopotential |--------------------------------------------------------| | | Ocean tides: applied, FES2014b model | | |--------------------------------------------------------| | | Solid Earth pole tide: applied according to IERS 2010 | | |--------------------------------------------------------| | | Oceanic pole tide: applied according to IERS 2010 | |---------------------------------------------------------------------------| | Third-body | Sun, Moon, Jupiter, Venus, Mars as point masses | | |--------------------------------------------------------| | | Ephemeris: JPL DE421, Folkner et al. (2009) | | |--------------------------------------------------------| | | GMsun = 132712500000 km**3/sec**2 | | |--------------------------------------------------------| | | GMmoon = 4902.7890 km**3/sec**2 | |---------------------------------------------------------------------------| | Solar radiation | A priori GPS: no a priori model | | pressure model | A priori GLONAS: no a priori model | | (parameter |--------------------------------------------------------| | estimation is | Earth shadow model: cylindrical shadow | | below) |--------------------------------------------------------| | | Earth albedo: numerical model according to | | | Rodriguez et al. (2012) | | |--------------------------------------------------------| | | Moon shadow model: umbra and penumbra | | |--------------------------------------------------------| | | Satellite attitude: nominal attitude | | |--------------------------------------------------------| | | Satellite antenna thrust: | | | Antenna thrust for GPS satellites according to | | | http://acc.igs.org/orbits/thrust-power.txt | | | Block I, II, IIA: 76 W | | | Block IIR: 85 W | | | Block IIR-M: 198 W (including M-code) | | | Block IIF: 249 W (including M-code) | | | SVN62 after 05 April 2011: 154 W (no M-code) | | | Block IIIA: 300 W (assumed value) | | | | | | Assumption for all GLONASS satellites: 100 W | |---------------------------------------------------------------------------| | Relativistic | dynamical correction: applied according to IERS 2010, | | effects | eq. 10.12, Lense-Thirring & | | | geodesic precession neglected | | |--------------------------------------------------------| | | Gravitational time delay: applied according to | | | IERS 2010, eq. 11.17 | |---------------------------------------------------------------------------| | Numerical | Integration algorithms developed at AIUB by Gerhard | | Integration | Beutler (1990). Representation of the orbit by a | | | polynomial of degree 10 for 5 minutes | | |--------------------------------------------------------| | | Integration step: 5 minutes | | |--------------------------------------------------------| | | Starter procedure: no special starter procedure needed | | |--------------------------------------------------------| | | Arc length: 72 hours long-arc solutions | ============================================================================= ============================================================================= | ESTIMATED PARAMETERS (& APRIORI VALUES & CONSTRAINTS) | |---------------------------------------------------------------------------| | Adjustment | Weighted least-squares algorithms | | method | | |---------------------------------------------------------------------------| | Data Span | Long-arc solutions include the data from three days, | | | combined on normal equation level | | | (Satellite orbits and troposphere | | | parameters are extracted from the middle day) | |---------------------------------------------------------------------------| | Station | All station coordinates are adjusted with minimum | | coordinates | constraints, see above. | |---------------------------------------------------------------------------| | Satellite clocks | Not applicable for double difference processing | | | | | | For clock estimation, the geometry from a double-diff. | | | solution is introduced as known (back-substitution) and| | | satellite clock parameters are estimated every 5 min. | | | in a full least-squares solution using code and phase | | | measurements. This step includes phase bias estimation | | | and ambiguity resolution. These 5 minute clock | | | solutions are densified to 30 second sampling with a | | | phase-based interpolation (see Bock et al., 2009). | | | In another step a further densification to 5 seconds | | | using the real-time data from the IGS real-time network| | | is performed. | |---------------------------------------------------------------------------| | Receiver clocks | Not applicable for double difference processing | | | | | | Receiver clocks are co-estimated with the satellite | | | clocks even if they are only distributed in the | | | product files with a sampling of 5 minutes. | | | | | | The reference clock is realised for the estimation | | | by a zero-mean condition; after the clock estimnation | | | the best performing receiver clock is selected as | | | the linear reference clock. | |---------------------------------------------------------------------------| | Orbital | 6 Keplerian elements plus 9 solar radiation parameters | | parameters | at start of arc; no a priori sigmas used. | | | Estimated SRP parameters (see Beutler et al. 1994, | | | Arnold et al. 2015): | | | - Constants in D-, Y- and X-direction | | | - Periodic 1 per rev. terms in X-direction | | | - Periodic 2 per rev. terms in D-direction | | | | | | Pseudo-stochastic orbit parameters (small velocity | | | changes) at orbit midnight constrained to: | | | . 1.E-6 m/sec in radial | | | . 1.E-5 m/sec in along-track | | | . 1.E-8 m/sec in out-of-plane | |---------------------------------------------------------------------------| | Satellite | Not estimated, according to nominal attitude model | | attitude | (see above) | |---------------------------------------------------------------------------| | Troposphere | Zenith delay: estimated for each station in intervals | | | of 2 hours. Loose relative constraints of| | | 5 m are applied. Piece-wise, linear | | | parametrization, allowing for connection | | | of the parameters at day boundaries. | | |--------------------------------------------------------| | | Zenith delay epochs: every two hours starting at | | | midnight | | |--------------------------------------------------------| | | Mapping function: wet VMF1 | | |--------------------------------------------------------| | | Gradients: pairs of horizontal delay gradient | | | parameters are estimated in N-S and E-W | | | direction for each station in intervals of | | | 24 hours. Loose relative constraints of | | | 5 m are applied. Piece-wise, linear | | | parametrization, allowing for connection of | | | the parameters at day boundaries. | | | Details about the gradient model can be | | | found in Rothacher et al. (1997). | | | Refined gradient model used, see Chen and | | | Herring (1997). | |---------------------------------------------------------------------------| | Ionospheric | Not estimated in ionosphere-free analyses | | correction | | | | One scaling factor for 2nd and 3rd order terms and ray | | | bending is setup to switch the components on or off | | | on normal equation level. | | | The products are generated with considering all three | | | correction components. | |---------------------------------------------------------------------------| | Ambiguity | Geometry estimation: double-difference approach: | | | Ambiguities are resolved in a baseline-by-baseline | | | mode performing the following steps for GPS | | | . Melbourne-Wuebbena approach (< 6000 km) | | | . Quasi-Ionosphere-Free (QIF) approach (< 2000 km) | | | (also for GLONASS, same frequencies) | | | . Phase-based widelane/narrowlane method (< 200 km) | | | (also for GLONASS, no restrictions) | | | . Direct L1/L2 method, also for GLONASS (< 20 km) | | | (also for GLONASS, no restrictions) | | | GNSS-derived global ionosphere map information is used | | | to support the code-less methods. | | | | | | Clock estimation: zero-difference approach: | | | Ambiguities are resolved station by station in a | | | single-difference mode (satellite to satellite) for | | | GPS. | | | . Melbourne-Wuebbena approach | | | . Narrowlane method | |---------------------------------------------------------------------------| | Earth Orient. | X- and Y-pole coordinates, and UT1-UTC are represented | | Parameters (EOP) | each with piece-wise linear polynomials which are | | | continuous in time. UT1-UTC is fixed to the a priori | | | value at the beginning of the first day. No further | | | a priori sigmas are used. | | | | | | All reported CODE EOP solutions do include a subdaily | | | EOP model (see above). The estimates therefore | | | correspond to daily averages on top of the introduced | | | a priori model. | |---------------------------------------------------------------------------| | Other | Center of mass coordinates: | | parameters | | | | Center of mass, or geocenter coordinate parameters are | | | commonly set up as part of each solution. The related | | | parameters are usually heavily constrained to zero | | | values. Additional computations on the normal equation | | | level are made regularly in order to retrieve 1-day, | | | 3-day, as well as weekly GNSS geocenter coordinates in | | | the current ITRF. | | | | | | GNSS satellite phase center offsets and patterns: | | | | | | Corresponding parameters are commonly set up as part | | | of each final solution for each individual GNSS | | | satellite. The related parameters are again removed | | | from the normal equation before the solution is | | | computed to fix parameters to the nominal values (as | | | defined by the IGS08 PCV model). Such GNSS PCV | | | parameters are available for the ionosphere-free as | | | well as the geometry-free linear combination. | | | | | | GPS/GLONASS bias parameter: | | | | | | An extra set of six parameters is set up for each | | | GLONASS observing station to characterize: | | | - one GLONASS-GPS receiver antenna offset vector | | | (three components) and | | | - one GLONASS-GPS ZPD and gradient troposphere bias | | | These biases are estimated on a weekly basis together | | | with the station coordinates. | | | For the product generation these bias parameters are | | | set to zero. | | | | ============================================================================= ============================================================================= | REFERENCES |---------------------------------------------------------------------------- Bassiri, S., and G.A. Hajj (1993), Higher-order ionospheric effects on Global Positioning System observables and means of modeling them, Manuscripta Geodaetica, vol. 18, pp. 280-289 Beutler, G. (1990), Numerische Integration gewoehnlicher Differential- gleichungssysteme: Prinzipien und Algorithmen. Mitteilungen der Satelliten-Beobachtungsstation Zimmerwald, No. 23, Druckerei der Universitaet Bern Beutler, G., E. Brockmann, W. Gurtner, U. Hugentobler, L. Mervart, and M. Rothacher (1994), Extended Orbit Modeling Techniques at the CODE Processing Center of the International GPS Service for Geodynamics (IGS): Theory and Initial Results, Manuscripta Geodaetica, vol. 19, pp. 367-386 Bock, H., R. Dach, A. Jaeggi, G. Beutler (2009): High-rate GPS clock corrections from CODE: Support of 1 Hz applications. Journal of Geodesy, vol. 83(11), pp. 1083-1094, DOI 10.1007/s00190-009-0326-1. Boehm, J., B. Werl, and H. Schuh (2006), Troposphere mapping functions for GPS and very long baseline interferometry from European Centre for Medium-Range Weather Forecasts operational analysis data, Journal of Geophysical Research, vol. 111, B02406, doi:10.1029/2005JB003629 Brunner, FK., and M. Gu (1991), An improved model for the dual frequency ionospheric correction of GPS observations, Manuscripta Geodaetica, vol. 16, pp. 205-214 Chen and Herring (1997), Effects of atmospheric azimuthal asymmetry on the analysis of space geodetic data, Journal of Geophysical Research, vol. 102(B9), pp. 20489-20502, doi:10.1029/97JB01739 Dach, R., E. Brockmann, S. Schaer, G. Beutler, M. Meindl, L. Prange, H. Bock, A. Jäggi, L. Ostini (2009), GNSS processing at CODE: status report, Journal of Geodesy, vol. 83(3-4), pp. 353-366 Dach, R., S. Lutz, P. Walser, P. Fridez (Eds); 2015: Bernese GNSS Software Version 5.2. User manual, Astronomical Institute, University of Bern, Bern Open Publishing. 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Swift (1992), Global Positioning System radiation force model for geodetic applications. Journal of Geophysical Research, vol. 97(B1), pp. 559-568 GSA (2019). Galileo IOV and FOC satellite metadata. https://www.gsc-europa.eu/support-todevelopers/galileo-iov-satellite-metadata Kouba, J. (2007), Implementation and testing of the gridded Vienna Mapping Function 1 (VMF1), Journal of Geodesy, vol. 82(4-5), pp. 193-205, doi: 10.1007/s00190-007-0170-0 McCarthy, D.D., G. Petit (eds.) (2010), IERS Conventions (2010). IERS Technical Note 36, Bundesamt fuer Kartographie und Geodaesie Pavlis, N.K., S.A. Holmes, S.C. Kenyon, J.K. Factor (2012). The development and evaluation of the Earth Gravitational Model 2008 (EGM2008), Journal of Geophysical Research, vol. 117, B04406, doi:10.1029/2011JB008916 Rodriguez-Solano, C. J., U. Hugentobler, P. Steigenberger (2012) Impact of albedo radiation on GPS satellites; in: S.C. Kenyon, M.C. Pacino, U.J. Marti, (eds.) Geodesy for Planet Earth, IAG Symposia, Vol. 136, pp. 113-119, Springer, DOI: 10.1007/978-3-642-20338-1_14 Rothacher, M., T.A. Springer, S. Schaer, G. Beutler (1997), Processing Strategies for Regional GPS Networks, IAG Symposia, vol. 118, pp. 93-100 Folkner, W.M., J.G. Williams, D.H. Boggs (2009), The Planetary and Lunar Ephemeris DE421, IPN Progress Report 42-178 Schaer, S. (1999), Mapping and Predicting the Earth's Ionosphere Using the Global Positioning System, Geodaetisch-geophysikalische Arbeiten in der Schweiz, vol. 59 Schaer, S., A. Villiger, D. Arnold, R. Dach, A. Jaeggi, L. Prange (2020). The CODE ambiguity-fixed clock and phase bias analysis products: generation, properties, and performance. Journal of Geodesy, in review. Sidorov, D., R. Dach, B. Polle, L. Prange, A. Jaeggi (2020). Adopting the Empirical CODE Orbit Model to Galileo satellites. Advances in Space Research, 2020, in press. DOI 10.1016/j.asr.2020.05.028 Wu, J.T., S.C. Wu, G.A. Hajj, W.I. Bertiger, S.M. Lichten (1993), Effects of antenna orientation on GPS carrier phase. Manuscripta Geodaetica, vol. 18, pp. 91-98