MGEX
GIOVE

This page provides an overview of the Galileo In-Orbit Validation Element (GIOVE) satellites, namely GIOVE-A and GIOVE-B.

Satellites

Common Name SVN Int. Sat. ID NORAD ID PRN Notes
GIOVE-A E001 2005-051A 28922 E01/E51 Decommissioned 2012/06/30
GIOVE-B E002 2008-020A 32781 E16/E52 Decommissioned 2012/07/23

Note: Due to the late announcement of official space vehicle identifiers for the GIOVE-A/B satellites, different PRN assignments have been adopted by receiver manufacturers and data providers for these satellites. While PRN numbers E01/E16 have been used within the broadcast navigation messages of GIOVE-A/B other possible identifications include

  • PRN E01/E02 (Javad receivers)
  • PRN E32/E31 (Septentrio PolaRx/AsteRx receivers)
  • PRN E51/E52 (Septentrio GeNeRx1 receiver, NovAtel EuroPak15a, Trimble NetR9 receiver, RTCM3-MSM draft)
  • PRN E01/E16 (Leica GRX1200+GNSS/GR10/GR25 receivers)

So far, no unique PRN numbering scheme has been adopted within the IGS and RINEX files collected within the MGEX project may be based on either of the above conventions. Users of MGEX data prior to the deactivation of GIOVE-A/B in the summer of 2012 are advised to carefully check the employed data and adjust the PRN numbers to ensure consistency in their processing where needed. In particular, attention should be paid to the fact, that different PRN conventions might be used concurrently in data products resulting from the same receiver but using different RINEX generation tools.

Spacecraft Characteristics

A comprehensive collection of technical information with associated references for the GIOVE-A and GIOVE-B spacecraft can be obtained at ESA's eoPortal as well as the ESA report on GIOVE Experimentation Results (ESA SP-1320).

Parameter GIOVE-A GIOVE-B
Launch mass 602 kg 530 kg
Dry mass 550 kg 502 kg
Body size 1.3 m x 1.8 m x 1.65 m (stowed envelope) 0.95 m x 0.95 m x 2.4 m
Solar array size 2 x 2 x 1.74 m x 0.98 m 2 x 4 x 1.5 m x 0.8 m
Span width ~10 m ~10 m
Cross section 9 m2 12 m2
SRP acceleration 99 nm/s2 151 nm/s2

The GIOVE-A/B spacecraft are equipped with broadband GNSS antennas for the E1, E5ab and E6 frequency bands and with a laser retroreflector array (LRA) for satellite laser ranging.


Fig. 1 Spacecraft reference system and sensor location for the GIOVE-A (left), GIOVE-B (right) satellites. Blue arrows and labels indicate the reference system adopted by the IGS, while the manufacturer-specific systems are illustrated in red. During nominal yaw-steering, the Sun is always confined to the +xIGS-hemisphere. Reproduced from DOI 10.1016/j.asr.2015.06.019 with permission of Elsevier; satellite images courtesy ESA.

Phase center coordinates of the GNSS antenna and the LRA of GIOVE-A/B satellites as recommended for use within the MGEX project are provided in the following table. A machine-readable version of the phase center offset information for each satellite is provided as part of the IGS14 ANTEX product. All values refer to the IGS-specific spacecraft coordinate system illustrated in blue in Fig. 1. The spacecraft coordinate system is aligned with the main body axes and originates near the anti-Earth panel. By convention of the IGS
  • the +zIGS-axis is oriented along the boresight direction of the antenna,
  • the yIGS-axis is parallel to the rotation axis of the solar panels and the positive yIGS-direction is defined through the adopted +xIGS-direction,
  • the +xIGS-axis completes a right handed system and is chosen such that the Sun is always located in the +xIGS hemisphere during nominal yaw-steering.
The detailed orientation of the +xIGS and +yIGS-axes for individual satellites is defined as shown in the drawings.

GIOVE-A
  Coordinates (w.r.t. origin) Coordinates (w.r.t. CoM) Reference
xIGS yIGS zIGS xIGS yIGS zIGS
GNSS Antenna E1 0.0 mm 0.0 mm +1658.0 mm -4.0 mm +1.0 mm +862.0 mm [1]
E5a/b/ab 0.0 mm 0.0 mm +1690.0 mm -4.0 mm +1.0 mm +894.0 mm [1]
E6 0.0 mm 0.0 mm +1665.0 mm -4.0 mm +1.0 mm +869.0 mm [1]
LRA   +832.0 mm +654.0 mm +1476.0 mm +828.0 mm +655.0 mm +680.0 mm [1]
CoM (Mar 2006)   +4.0 mm -1.0 mm +796.0 mm       [1]

GIOVE-B
  Coordinates (w.r.t. origin) Coordinates (w.r.t. CoM) Reference
xIGS yIGS zIGS xIGS yIGS zIGS
GNSS Antenna E1 0.0 mm 0.0 mm +2289.2 mm -3.2 mm +3.4 mm +1351.7 mm [1]
E5a/b/ab 0.0 mm 0.0 mm +2288.7 mm -3.2 mm +3.4 mm +1351.2 mm [1]
E6 0.0 mm 0.0 mm +2287.6 mm -3.2 mm +3.4 mm +1350.1 mm [1]
LRA   +807.5 mm -297.5 mm +2267.6 mm +804.3 mm -294.1 mm +1330.1 mm [1]
CoM (BoL)   +3.2 mm -3.4 mm +937.5 mm       [1]

GNSS antenna offsets for GIOVE-A/B are based on calibrated phase centers for each frequency band and center-of-mass information for the begin of life (BoL) as provided by ESA.
For the modelling of satellite laser ranging measurements nominal coordinates of the effective LRA reflection point have been specified by ESA as part of the ILRS mission support request.

Similar to the GPS satellites the attitude of the GIOVE satellites is actively controlled to orient the +zIGS axis towards the Earth. At the same time the spacecraft is continuously rotated about this axis to maintain the yIGS-axis perpendicular to the plane made up by the Sun, Earth, and satellite. The +xIGS-panel is always sunlit, while the -xIGS-panel is oriented towards "deep space". Details of the attitude control during noon- and midnight turns in periods when the Sun is close to the orbital plane are described in [2] and [3].

References

[1] Zandbergen R., Navarro D.; "Specification of Galileo and GIOVE Space Segment properties relevant for Satellite Laser Ranging", ESA-EUING-TN/10206, Issue 3.2, 08/05/2008, Galileo Project Office, ESA, Noordwijk;
[2] Johnston A.G.Y., Holt A.P., Jackson C.D., "GIOVE-A AOCS : An Experience from Verification to Flight", 7th Int. ESA Conference on Guidance, Navigation & Control Systems, 2-5 June 2008, Tralee, County Kerry, Ireland (2008).
[3] Zentgraf P., Fischer H.-D., Kaffer L., Konrad A., Lehrl E., Müller C., Oesterlin W., Wiegand M.; "AOC Design and Test for GSTB-V2B", 6th Int. ESA Conference on Guidance, Navigation and Control Systems, 17-20 Oct. 2005 in Loutraki, Greece (2005).


Events

Date UTC Satellite PRN Description Notes
2011/11/25   GIOVE-B E16/E52 Clock switch (PHM to Rb) CONGO monitoring
2012/02/27   GIOVE-B E16/E52 End of transmission outage CONGO monitoring
2012/06/30 21:00 GIOVE-A E01/E51 End of mission ESA
2012/07/23 11:14 GIOVE-B E16/E52 End of mission ESA




Last Updated: 2017/01/23 13:49:31
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