Arnold, Daniel

Beutler, Gerhard

Dach, Rolf

Jäggi, Adrian

Orliac, Etienne

Prange, Lars

Schaer, Stefan

Bern Open Repository and Information System (BORIS)

   Astronomical Institute, University of Bern, Switzerland Federal office of topography swisstopo, Wabern, Switzerland  IGS Workshop, 8-12 February 2016, Sydney, Australia   Astronomical Institute University of Bern Impact of the SRP model on CODE's 5-system orbit and clock solution for the MGEX L. Prange, E. Orliac, R. Dach, D. Arnold, G. Beutler, S. Schaer, A. Jäggi source: https://doi.org/10.7892/boris.87825 | downloaded: 13.3.2017Astronomical Institute University of Bern Contents  l  Data base and network l  CODE MGEX orbit solution l  CODE MGEX clock solution l  Impact of CODE‘s new solar radiation pressure model l  Summary and outlook L. Prange et al.: Impact of the SRP model on CODE's 5-system orbit and clock solution for the MGEX, IGS Workshop, Sydney, Australia, 8-12 February 2016 Astronomical Institute University of Bern  MGEX data  monitoring Number of stations providing daily RINEX3 files and included in CODE‘s raw data monitoring (data sources: IGS-MGEX and EPN)  L. Prange et al.: Impact of the SRP model on CODE's 5-system orbit and clock solution for the MGEX, IGS Workshop, Sydney, Australia, 8-12 February 2016 Astronomical Institute University of Bern CODE MGEX orbit solution  GNSS considered:  GPS + GLONASS + Galileo + BeiDou (MEO+IGSO) + QZSS (≈70 SV) Processing mode: Post-processing (≈2 weeks latency) Timespan covered: GPS-weeks 1689 - today Number of stations:  130 (GPS), 110 (GLONASS),  85 (Galileo); 55 (BeiDou); 20 (QZSS) Processing scheme: Double-difference network processing  (observable: phase double differences) Signal frequencies: L1+ L2 (GPS + GLO+ QZSS);  E1 (L1) + E5a (L5) Galileo; B1 (L1) + B2 (L7) BeiDou Orbit characteristic: 3-day long arcs; SRP: ECOM / ECOM2 (since 2015) Reference frame: IGS08 (until week 1708); IGb08 (since week 1709) IERS conventions: IERS2003 (until 1705); IERS2010 (since 1706) Product list: Daily orbits (SP3) and ERPs Distribution:  ftp://cddis.gsfc.nasa.gov/gnss/products/mgex/ and ftp://ftp.unibe.ch/aiub/CODE_MGEX/ Designator: comwwwwd.???.Z L. Prange et al.: Impact of the SRP model on CODE's 5-system orbit and clock solution for the MGEX, IGS Workshop, Sydney, Australia, 8-12 February 2016 Astronomical Institute University of Bern CODE MGEX clock solution  GNSS considered: GPS + GLONASS + Galileo + BeiDou + QZSS  (≈70 SV) Processing mode: Post-processing (≈2 weeks latency) Timespan covered: GPS-weeks 1710 - today Number of stations: 130 (GPS), 35 (GLO), 45 (Galileo); 50 (BeiDou); 20 (QZSS) Processing scheme: Zero-difference processing  (observable: code+phase undifferenced) Signal frequencies: L1+ L2 (GPS + GLO+ QZSS);  E1 (L1) + E5a (L5) Galileo; B1 (L1) + B2 (L7) BeiDou A priori information: Orbits, ERPs, coordinates, and troposphere from  CODE MGEX orbit solution introduced as known Reference frame: IGb08 IERS conventions: IERS2010 Product list: Epoch-wise (300s) satellite and station clock corrections  in daily clock RINEX files; daily inter-system biases for mixed stations in Bernese DCB and BIAS-SINEX format Distribution: ftp://cddis.gsfc.nasa.gov/gnss/products/mgex/ and ftp://ftp.unibe.ch/aiub/CODE_MGEX/ L. Prange et al.: Impact of the SRP model on CODE's 5-system orbit and clock solution for the MGEX, IGS Workshop, Sydney, Australia, 8-12 February 2016 Astronomical Institute University of Bern  MGEX products availability Status: 01-Jan-2016 Satellite system IDs according to the content of the precise orbit files at ftp://cddis.gsfc.nasa.gov/pub/gps/products/mgex/ L. Prange et al.: Impact of the SRP model on CODE's 5-system orbit and clock solution for the MGEX, IGS Workshop, Sydney, Australia, 8-12 February 2016 Astronomical Institute University of Bern  Orbit description and Yaw attitude Angles and vectors: Beta: Elevation of Sun above orbital plane Du: Argument of latitude Z: Direction satellite -> Earth (antenna direction) ECOM axes: D: Direction satellite -> Sun  Y: Solar panel axis B: Third ECOM axis Beta Du Z B Y D L. Prange et al.: Impact of the SRP model on CODE's 5-system orbit and clock solution for the MGEX, IGS Workshop, Sydney, Australia, 8-12 February 2016 Astronomical Institute University of Bern  Solar radiation pressure Satellite cross-section as seen from the Sun (Beta ≈ 30°)   during one orbital revolution:  => solar panel area does not change   => but: cross-section of long satellite bodies w.r.t. the Sun  varies    L. Prange et al.: Impact of the SRP model on CODE's 5-system orbit and clock solution for the MGEX, IGS Workshop, Sydney, Australia, 8-12 February 2016 Astronomical Institute University of Bern  New Empirical CODE radiation pressure Model l  MGEX-reprocessing for 2014 using ECOM (5 RPR par.; Beutler et al., 1994, Springer et al., 1999) vs. ECOM2 (9 RPR par., Arnold et al., 2015) l  Validation with SLR residuals and satellite clock corrections l  The new ECOM takes into account the periodically changing cross section of elongated satellite bodies wrt. the Sun => Improvements expected for Galileo, GLONASS, QZSS  ECOM1 (old): D(u) = D0  Y(u) = Y0 B(u) = B0 + BC cos(u) + BS sin(u)  ECOM2 (new): D(u) = D0 + D2C cos(2Du) + D2S sin(2Du)     + D4C cos(4Du) + D4S sin(4Du)  Y(u) = Y0 B(u) = B0 + BC cos(Du) + BS sin(Du) L. Prange et al.: Impact of the SRP model on CODE's 5-system orbit and clock solution for the MGEX, IGS Workshop, Sydney, Australia, 8-12 February 2016 Astronomical Institute University of Bern  Impact of new ECOM on Galileo orbits ⇒  Significant reduction of size and dependency of SLR residuals on the Beta-angle L. Prange et al.: Impact of the SRP model on CODE's 5-system orbit and clock solution for the MGEX, IGS Workshop, Sydney, Australia, 8-12 February 2016 Astronomical Institute University of Bern L. Prange et al.: Impact of the SRP model on CODE's 5-system orbit and clock solution for the MGEX, IGS Workshop, Sydney, Australia, 8-12 February 2016 ECOM1 (all Galileo satellites): ⇒  SLR residuals of 2014 are large at small and medium Beta angles and with argument of latitude around 0° and ±180°   Impact of new ECOM on Galileo orbits Astronomical Institute University of Bern L. Prange et al.: Impact of the SRP model on CODE's 5-system orbit and clock solution for the MGEX, IGS Workshop, Sydney, Australia, 8-12 February 2016  Impact of new ECOM on Galileo orbits ECOM2 (all Galileo satellites): ⇒  Systematics in the SLR residuals are significantly reduced ⇒  Significant SLR offset remains Astronomical Institute University of Bern ⇒  Significant reduction of Beta angle dependency ⇒  Pronounced signal remains during eclipse season or close-by (impact of mis-modelled attitude?)  Impact of new ECOM on Galileo clock corrections L. Prange et al.: Impact of the SRP model on CODE's 5-system orbit and clock solution for the MGEX, IGS Workshop, Sydney, Australia, 8-12 February 2016 Astronomical Institute University of Bern L. Prange et al.: Impact of the SRP model on CODE's 5-system orbit and clock solution for the MGEX, IGS Workshop, Sydney, Australia, 8-12 February 2016  Impact of new ECOM on Galileo clock corrections Small beta-angle:  => Periodic signal caused by mis-modelled orbit (ECOM1) => Significant reduction of signal amplitude   from ±0.75 ns  to ±0.15 ns (ECOM2) Large beta-angle: => Clock signal has small amplitude   (about ±0.15 ns) Astronomical Institute University of Bern  Impact of new ECOM on QZSS orbits ⇒  ECOM2 reduces dependency on Beta angle ⇒  Significant SLR offset remains L. Prange et al.: Impact of the SRP model on CODE's 5-system orbit and clock solution for the MGEX, IGS Workshop, Sydney, Australia, 8-12 February 2016 Astronomical Institute University of Bern  Impact of new ECOM on QZSS orbits ⇒  Large orbit errors occur at |ß| < 20° (marked grey) ⇒  Test of new ECOM version suited for orbit normal attitude mode L. Prange et al.: Impact of the SRP model on CODE's 5-system orbit and clock solution for the MGEX, IGS Workshop, Sydney, Australia, 8-12 February 2016 Astronomical Institute University of Bern L. Prange et al.: Impact of the SRP model on CODE's 5-system orbit and clock solution for the MGEX, IGS Workshop, Sydney, Australia, 8-12 February 2016  Impact of new ECOM on QZSS orbits ECOM1: ⇒  |ß| < 20°: SLR residuals of 2014 are dominated by not correctly considered orbit normal attitude mode ⇒  |ß| > 20°: correlation with Beta angle and argument of latitude Astronomical Institute University of Bern L. Prange et al.: Impact of the SRP model on CODE's 5-system orbit and clock solution for the MGEX, IGS Workshop, Sydney, Australia, 8-12 February 2016  Impact of new ECOM on QZSS orbits ECOM2: ⇒  |ß| < 20°: SLR residuals remain large ⇒  |ß| > 20°: systematics in the SLR residuals are reduced ⇒  SLR offset remains Astronomical Institute University of Bern ⇒  Significant reduction of Beta angle dependency at Yaw attitude thanks to ECOM2 ⇒  Large errors remain at orbit normal attitude  Impact of new ECOM on QZSS clock corrections L. Prange et al.: Impact of the SRP model on CODE's 5-system orbit and clock solution for the MGEX, IGS Workshop, Sydney, Australia, 8-12 February 2016 Astronomical Institute University of Bern  Impact of new ECOM on QZSS clock corrections ⇒  Significant reduction of Beta angle dependency at Yaw attitude thanks to ECOM2  ⇒  Experiments with ECOM version suited for normal attitude mode L. Prange et al.: Impact of the SRP model on CODE's 5-system orbit and clock solution for the MGEX, IGS Workshop, Sydney, Australia, 8-12 February 2016 Astronomical Institute University of Bern L. Prange et al.: Impact of the SRP model on CODE's 5-system orbit and clock solution for the MGEX, IGS Workshop, Sydney, Australia, 8-12 February 2016  Impact of new ECOM on BeiDou orbits ⇒  No significant impact of new ECOM on BeiDou orbits ⇒  Large residuals for |ß| < 4° (marked grey), because orbit normal attitude not yet correctly considered Astronomical Institute University of Bern  Impact of new ECOM on GLONASS orbits ⇒  Moderate reduction of SLR residuals at low Beta angles for majority of GLONASS satellites  L. Prange et al.: Impact of the SRP model on CODE's 5-system orbit and clock solution for the MGEX, IGS Workshop, Sydney, Australia, 8-12 February 2016 Astronomical Institute University of Bern L. Prange et al.: Impact of the SRP model on CODE's 5-system orbit and clock solution for the MGEX, IGS Workshop, Sydney, Australia, 8-12 February 2016  Impact of new ECOM on GLONASS orbits ECOM1:  ⇒  Moderate correlation of SLR residuals from 2014 with Beta angle and argument of latitude R24 SVN735 R24 SVN735 R24 SVN735 Astronomical Institute University of Bern L. Prange et al.: Impact of the SRP model on CODE's 5-system orbit and clock solution for the MGEX, IGS Workshop, Sydney, Australia, 8-12 February 2016  Impact of new ECOM on GLONASS orbits ECOM2:  ⇒  Systematics in the SLR residuals are reduced for most GLONASS satellites R24 SVN735 R24 SVN735 R24 SVN735 Astronomical Institute University of Bern  Impact of new ECOM on GLONASS - exceptions But: ECOM2 does not work well for all GLONASS satellites (related to attitude issues?) L. Prange et al.: Impact of the SRP model on CODE's 5-system orbit and clock solution for the MGEX, IGS Workshop, Sydney, Australia, 8-12 February 2016 Astronomical Institute University of Bern Summary  l  Galileo, QZSS: significant improvement of orbits and clocks with ECOM2, when in yaw-attitude l  GLONASS: moderate orbit improvement with ECOM2 for the majority of satellites; degradation for some satellites l  ECOM2 is possibly more sensitive to attitude mis-modellings (compared to ECOM1) l  Normal attitude steering mode at low beta-angles causes very large orbit errors if not correctly considered l  Stable satellite clocks (GPS IIF, Galileo PHM, QZSS) are well suited for orbit validation l  Reprocessing of data from 2015 planned L. Prange et al.: Impact of the SRP model on CODE's 5-system orbit and clock solution for the MGEX, IGS Workshop, Sydney, Australia, 8-12 February 2016 Astronomical Institute University of Bern  Thank you for  your interest! 

Impact of the SRP model on CODE's 5-system orbit and clock solution for the MGEX.

http://boris.unibe.ch/87825/1/W2016-PY0204-Prange.pdf

Impact of the SRP model on CODE's 5-system orbit and clock solution for the MGEX.

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