This page provides an overview of the Satellites in the BeiDou Navigation Satellite System (BDS). Technical parameters of the indivdual satellites and related conventions applied within the MGEX project are summarized in the Spacecraft Characteristics section. Furthermore, a list of Events of interest for the BDS data processing is given.
The regional BeiDou Navigation Satellite System (BDS-2, earlier referred to as COMPASS) comprises a total of 15 launched satellites out of which 13 were fully operational in 2015.
In mid 2015, China started the build-up of the 3rd generation BeiDou system (BDS-3) which will shall offer a fully global navigation service by 2020. So far, five BDS-3S in-orbit validation satellites have been launched.
BeiDou-2 |
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Common Name |
SVN |
Int. Sat. ID |
NORAD ID |
PRN |
Notes |
BEIDOU M1 | C001 | 2007-011A | 31115 | C30 | Decommissioned |
BEIDOU G2 | C002 | 2009-018A | 34779 | n/a | Inactive; uncontrolled |
BEIDOU G1 | C003 | 2010-001A | 36287 | C01 | 140.0° E |
BEIDOU G3 | C004 | 2010-024A | 36590 | C03 | 110.5° (moved from 84.0° to new position between Nov 7 and 22, 2012) |
BEIDOU G4 | C006 | 2010-057A | 37210 | C04 | 160.0° E |
BEIDOU IGSO 1 | C005 | 2010-036A | 36828 | C06 | ~122° E |
BEIDOU IGSO 2 | C007 | 2010-068A | 37256 | C07 | ~119° E |
BEIDOU IGSO 3 | C008 | 2011-013A | 37384 | C08 | ~120° E |
BEIDOU IGSO 4 | C009 | 2011-038A | 37763 | C09 | ~96.5° E |
BEIDOU IGSO 5 | C010 | 2011-073A | 37948 | C10 | ~92.5° E |
BEIDOU G5 | C011 | 2012-008A | 38091 | C05 | 58.75° E |
BEIDOU M3 | C012 | 2012-018A | 38250 | C11 | Slot A-7 |
BEIDOU M4 | C013 | 2012-018B | 38251 | C12 | Slot A-8 |
BEIDOU M5 | C014 | 2012-050A | 38774 | C13 | Slot B-3; End of signal transmission 21 Oct. 2014 |
BEIDOU M6 | C015 | 2012-050B | 38775 | C14 | Slot B-4 |
BEIDOU G6 | C016 | 2012-059A | 38953 | C02 | 80.3°E |
BEIDOU IGSO 6 | C017 | 2016-021A | 41434 | C15/C13 | ~95° E; launched 2016/03/29; PRN switch from C15 to C13 on 2016/10/11 |
BEIDOU G7 | C018 | 2016-037A | 41586 | C17 | launched 2016/06/12 |
BeiDou-3 | |||||
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Common Name |
SVN |
Int. Sat. ID |
NORAD ID |
PRN |
Notes |
BEIDOU I1-S | C101 | 2015-019A | 40549 | C31 | ~95° E; launched 2015/03/30; CAS |
BEIDOU M1-S | C102 | 2015-037B | 40749 | C33 | Slot A-1, launched 2015/07/30; CAST |
BEIDOU M2-S | C103 | 2015-037A | 40748 | C34 | Slot A-6, launched 2015/07/30; CAST |
BEIDOU I2-S | C104 | 2015-053A | 40938 | C32 | ~95° E; launched 2015/09/29; CAST |
BEIDOU M3-S | C105 | 2016-006A | 41315 | C35 | Slot B-1; launched 2016/02/01; CAS |
BEIDOU-3 M1 | C106 | 2017-069A | 43001 | C19 | Slot B-7; launched 2017/11/05 |
BEIDOU-3 M2 | C107 | 2017-069B | 43002 | C20 | Slot B-5; launched 2017/11/05 |
In the absence of official space vehicle numbers (SVNs), preliminary numbers for the above satellites have been assigend for use within the MGEX project based on the launch sequence of the respective spacecraft. PRN numbers have been associated with the individual satellites based on comparison of transmitted ranging codes with code sequences in the BeiDou Interface Control Document (ICD). The latest version of the Open Service Signal ICD ( BeiDou Navigation Satellite System Signal In Space Interface Control Document - Open Service Signal (Version 2.1)) covers the B1I and B2I signals and has been released in November 2016.
The five BEIDOU ??-S satellites are experimental satellites of the BeiDou-3 constellation manufactured by China Academy of Science (CAS) and China Academy of Space Technology (CAST), see [5].
Note: the association of PRN/SVN and NORAD/Int.Sat.ID numbers for BEIDOU M1-S and M2-S in the above table has been corrected on 02-Nov-2017 based on information from ILRS/SHAO.
BeiDou-2
A comprehensive collection of technical information with associated references for the BeiDou-2 satellites can be obtained at the CNSS page of ESA's eoPortal .
BeiDou-2 |
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Parameter |
GEO |
IGSO |
MEO |
Satellite Bus | DFH-3B | DFH-3B | DFH-3 (?) |
Launch mass | 4600 kg | 4200 kg | |
Dry mass | 1550 kg | 1900 kg | |
Body size | ~1.8 m x ~2.2 m x ~2.5 m | ~1.8 m x ~2.2 m x ~2.5 m | ~1.8 m x ~2.2 m x ~2.5 m |
Solar array size | 2 x 3 x 2.2 m x 1.7 m | 2 x 3 x 2.2 m x 1.7 m | 2 x 3 x 2.2 m x 1.7 m |
Span width | ~17.7 m | ~17.7 m | ~17.7 m |
Cross section | ~27 m2 | ~27 m2 | ~27 m2 |
SRP acceleration | 102 nm/s2 | 122 nm/s2 |
The BeiDou-2 spacecraft are equipped with broadband GNSS antennas for the B1, B2, and B3 frequency bands as well as a laser retroreflector array (LRA) for satellite laser ranging.
Phase center coordinates of the BeiDou-2 GNSS antenna and the LRA 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 Fig. 1. This system is aligned with the main body axes and originates in the plane opposite to the antenna. For all three spacecraft types
- 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 +xIGS-axis completes a right handed system.
BeiDou-2 GEO/IGSO/MEO | ||||||||
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Coordinates (w.r.t. origin) | Coordinates (w.r.t. CoM) | Reference | ||||||
xIGS | yIGS | zIGS | xIGS | yIGS | zIGS | |||
GNSS Antenna | B1, B2, B3 | +600.0 mm | 0.0 mm | +1100.0 mm | ||||
CoM (BoL) | G1 | +1152.0 mm | +0.2 mm | +0.0 mm | [1] | |||
I3, I5 | +1075.6 mm | +0.0 mm | -0.4 mm | [1] | ||||
M1, M3 | +1082.0 mm | -0.4 mm | -0.5 mm | [1] | ||||
LRA | G1 | +608.8 mm | -570.2 mm | +1093.0 mm | [1] | |||
I3, I5 | +673.0 mm | -573.0 mm | +1093.0 mm | [1] | ||||
M1, M3 | +649.9 mm | -562.5 mm | +1112.3 mm | [1] |
For the modelling of satellite laser ranging measurements nominal coordinates of the effective LRA reflection point have been specified by the China Satellite Navigation Engineering Center as part of the ILRS mission support request.
Due to a lack of publicly available antenna phase center offsets for the BeiDou-2 satellites, conventional values of (+0.6 m, 0.0 m, +1.1 m) are recommended for orbit and clock determination of the BeiDou-2 GEO/IGSO/MEO satellites until further notice. The values provide a first estimate of the actual phase center relative to the center of mass based on the images and models.
Based on actual BeiDou-2 GNSS observations, refined x-offsets of about +0.55 m values and z-offsets of 3-4 m and 2.0-2.5 m have been determined in [2] for the BeiDou-2 IGSO and MEO satellites, respectively, using a ionosphere-free B1/B2 combination. Even larger z-offsets were obtained for the ionosphere-free B1/B3 combination.
The attitude of the BeiDou-2 satellites is actively controlled to orient the +zIGS axis towards the Earth. For the MEO and IGSO satellites a yaw steering attitude is employed, in which the satellite is continuously rotated about the +zIGS axis to maintain the yIGS-axis perpendicular to the plane made up by the Sun, Earth, and satellite. Similar to the IGS satellites, the +xIGS-axis is pointed towards the sun-lit hemisphere. For the GEO satellites an orbit normal mode is adopted, in which the +yIGS is oriented perpendicular to the orbital plan. The orbit normal mode is also employed by the MEO/IGSO satellite when the Sun elevation above the orbital plane is less than about 4°. An overview of BeiDou-2 attitude modes and related mathematical formulations are provided in [3]. Mode transitions at low β-angles are further discussed in [4].
The latest BDS-2 IGSO satellite C017 does not enter orbit normal mode. F. Dilssner (ESOC) developed an attitude model for this satellite [6] and reports that the MEO satellite C015 and the IGSO satellite C005 follow also this attitude law since October 2016 and March 2017, respectively.
BeiDou-3S
BeiDou-3S stands for five BeiDou-3 test satellites launched in 2015/2016. They transmit legacy B1 signals similar to the BeiDou-2 satellites as well as modernized signals in the L1, E5, and B3 band.
Manufacturer satellite antenna phase center offsets as well as SLR retroreflector offsets for C101 - C104 are published in [5]. The M1S/M2S satellites are equipped with an additional fold-out phased array antenna. However, it is unknown which navigation signals are transmitted by this antenna.
BeiDou-3S |
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Parameter |
M1S/M2S |
M3S |
I1S |
I2S |
Mass | ~1000 kg | |||
Manufacturer | CAST | CAS | CAS | CAST |
Notes | First Chinese H-maser in space |
BeiDou-3
Build-up of the operational BeiDou-3 constellation was delayed by launcher issues and finally started in November 2017.
BeiDou-3 |
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Parameter |
MEO |
||
Launch mass | 1014 kg | ||
Body size | 2.25 m x 1.0 m x 1.22 m |
References
[1] ILRS BeiDou (COMPASS) Center of Mass Information[2] Dilssner F., Springer T., Schönemann E., Enderle W.; Estimation of satellite antenna phase center corrections for BeiDou. IGS Workshop, Pasadena, California, USA (2014).
[3] Montenbruck O., Schmid R., Mercier F., Steigenberger P., Noll C., Fatkulin R., Kogure S., Ganeshan A. S. (2015) GNSS satellite geometry and attitude models. Advances in Space Research 56(6):1015-1029. DOI 10.1016/j.asr.2015.06.019
[4] Dai X., Ge M., Lou Y., Shi C., Wickert J., Schuh H. (2015) Estimating the yaw-attitude of BDS IGSO and MEO satellites. Journal of Geodesy 89(10):1005-1018. DOI 10.1007/s00190-015-0829-x
[5] Zhao Q., Wang C., Guo J., Wang B., Liu J. (2018) Precise orbit and clock determination for BeiDou-3 experimental satellites with yaw attitude analysis. GPS Solutions 22:4. DOI 10.1007/s10291-017-0673-y
[6] Dilssner F. (2017) A note on the yaw attitude modeling of BeiDou IGSO-6
Date |
UTC |
Satellite |
PRN |
Description |
Notes |
---|---|---|---|---|---|
2012/04/06 | ~05:00 | G1 | C01 | E/W Maneuver dV=-0.09 m/s | TUM/DLR orbit analysis |
2012/05/02 | 11:01 | G1 | C01 | E/W Maneuver dV=-0.10 m/s | TUM orbit analysis |
2012/05/28 | 08:59 | G1 | C01 | E/W Maneuver dV=-0.10 m/s | TUM orbit analysis |
2012/04/16 | ~09:00 | G3 | C03 | E/W Maneuver dV=-0.08 m/s | TUM/DLR orbit analysis |
2012/04/23 | 07:32 | G4 | C04 | E/W Maneuver dV=-0.03 m/s | TUM orbit analysis |
2012/04/10 | n/a | G5 | C05 | E/W Maneuver dV=+0.13 m/s | TUM/DLR orbit analysis |
2012/05/23 | n/a | G5 | C05 | E/W Maneuver | TUM orbit analysis; badly observed |
2012/05/09 | 08:40 | I1 | C06 | Maneuver dV(RTN)=(0.00,-0.45,+0.18) m/s | TUM orbit analysis |
2012/05/16 | 10:00 | I2 | C07 | Maneuver dV(RTN)=(0.00,-0.57,-0.40) m/s | TUM orbit analysis |
2012/04/27 | 01:00 | I4 | C09 | Maneuver dV(RTN)=(-0.05,-0.32,-0.06) m/s | TUM orbit analysis |
2012/05/06 | 08:18 | M3 | C12 | Start of signal transmission | CONGO/MGEX monitoring |
2012/05/06 | 10:04 | M2 | C11 | Start of signal transmission | CONGO/MGEX monitoring |
2012/09/25 | M5 | C13 | Start of signal transmission | Trimble/CONGO/MGEX monitoring | |
2012/09/25 | M6 | C14 | Start of signal transmission | Trimble/CONGO/MGEX monitoring | |
2012/11/01 | G6 | C02 | Start of signal transmission | Trimble monitoring | |
2012/11/22 | G3 | C03 | Moved from 84.0°E (before 2012/11/01) to 110.5°E | CANSPACE | |
2014/10/21 | 04:15 | M5 | C13 | End of signal transmission | MGEX monitoring |
2015/05/04 | I1-S | C31 | Start of signal transmission | MGEX monitoring | |
2015/07/31 | 3M1 | C33 | Start of signal transmission | MGEX monitoring | |
2015/08/08 | 3M2 | C34 | Start of signal transmission | MGEX monitoring | |
2015/10/05 | I2-S | C32 | Start of signal transmission | MGEX monitoring | |
2016/04/06 | I6 | C15 | Start of signal transmission | MGEX monitoring | |
2016/10/11 | 4:52 | I6 | C15 | End of signal transmission | MGEX monitoring |
2016/10/11 | 7:42 | I6 | C13 | Restart of signal transmission with different PRN | MGEX monitoring |