MGEX
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BeiDou

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. Information about the operational status of BeiDou can be found on the website of the Test and Assessment Research Center of China Satellite Navigation Office

Satellites

The regional BeiDou Navigation Satellite System (BDS-2, earlier referred to as COMPASS) originally comprised a total of 15 launched satellites out of which 13 were fully operational in 2015. BDS-2 replacement satellites have been launched in 2016 and 2018. 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. In 2015/2016, five BDS-3S in-orbit validation satellites have been launched. Build-up of the operational BeiDou-3 constellation was delayed by launcher issues and finally started in November 2017.

BeiDou-2
SVN
Common Name
Int. Sat. ID
NORAD ID
Sat. Cat. Name
PRN
Notes
C001 BEIDOU M1 2007-011A 31115 COMPASS 2 C30 decommissioned; launched 2007-04-13
C002 BEIDOU G2 2009-018A 34779 BEIDOU C02 inactive; uncontrolled; launched 2009/04/14
C003 BEIDOU G1 2010-001A 36287 BEIDOU 3 C01 140.0°E; launched 2010/01/16
C004 BEIDOU G3 2010-024A 36590 BEIDOU 4 C03 110.5°E; launched 2010/06/02
C005 BEIDOU IGSO 1 2010-036A 36828 BEIDOU 5 C06 ~117°E; launched 2010/07/31
C006 BEIDOU G4 2010-057A 37210 BEIDOU 6 C04 160.0°E; launched 2010/10/31
C007 BEIDOU IGSO 2 2010-068A 37256 BEIDOU 7 C07 ~119°E; launched 2010/12/17
C008 BEIDOU IGSO 3 2011-013A 37384 BEIDOU 8 C08 ~117°E; launched 2011/04/09
C009 BEIDOU IGSO 4 2011-038A 37763 BEIDOU 9 C09 ~95°E; launched 2011/07/26
C010 BEIDOU IGSO 5 2011-073A 37948 BEIDOU 10 C10 ~96°E; launched 2011/12/01
C011 BEIDOU G5 2012-008A 38091 BEIDOU 11 C05 58.75°E; launched 2012/02/24
C012 BEIDOU M3 2012-018A 38250 BEIDOU 12 C11 Slot A-7; launched 2012/04/29
C013 BEIDOU M4 2012-018B 38251 BEIDOU 13 C12 Slot A-8; launched 2012/04/29
C014 BEIDOU M5 2012-050A 38774 BEIDOU 14 C13 Slot B-3; launched 2012/09/18;
end of signal transmission 21 Oct. 2014
C015 BEIDOU M6 2012-050B 38775 BEIDOU 15 C14 Slot B-4; launched 2012/09/18
C016 BEIDOU G6 2012-059A 38953 BEIDOU 16 C02 80.3°E; launched 2012/10/25
C017 BEIDOU IGSO 6 2016-021A 41434 BEIDOU IGSO-6 C15/C13 ~94°E; launched 2016/03/29;
PRN switch from C15 to C13 on 2016/10/11
C018 BEIDOU G7 2016-037A 41586 BD-2-G7 C17 144.5°E; launched 2016/06/12
C019 BEIDOU IGSO 7 2018-057A 43539 BEIDOU IGSO-7 C16 launched 2018/07/09

Notes:
  • In the absence of official space vehicle numbers (SVNs), preliminary numbers for the BDS-2 satellites have been assigend for use within the MGEX project based on the launch sequence of the respective spacecraft.
  • C004 was moved from 84.0° E to new position between Nov 7 and 22, 2012.

BeiDou-3S
SVN
Common Name
Int. Sat. ID
NORAD ID
Sat. Cat. Name
Manuf.
PRN
Notes
C101 BEIDOU I1-S 2015-019A 40549 BD-17 SECM C31/C16 ~93°E; launched 2015/03/30;
PRN switch from C31 to C16 on 2018/04/24
PRN switch from C16 to C31 on 2018/07/10
C102 BEIDOU M1-S 2015-037B 40749 BD-19 CAST C33/C19 Slot A-1, launched 2015/07/30;
PRN switch from C33 to C19 on 2018/06/14
C103 BEIDOU M2-S 2015-037A 40748 BD-18 CAST C34/C28 Slot A-6, launched 2015/07/30;
PRN switch from C34 to C28 on 2018/06/11
C104 BEIDOU I2-S 2015-053A 40938 BD-20 CAST C32/C18 ~96° E; launched 2015/09/29;
PRN switch from C32 to C18 on 2018/06/07
C105 BEIDOU M3-S 2016-006A 41315 BD-21 SECM C35 Slot B-1; launched 2016/02/01

Notes:
  • The five BEIDOU ??-S satellites are experimental satellites of the BeiDou-3 constellation manufactured by the Shanghai Engineering Center for Microsatellites (SECM) of the China Academy of Science (CAS) and China Academy of Space Technology (CAST), see [5].
  • 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.
  • No tracking of C35 so far. According to [8], C105 suffers from a failure of the transmit antenna.
  • No tracking of C34 since 11 June 2018
  • Only B1 single-frequency tracking of C101/C16 and C104/C18 after PRN switches in April/June 2018
  • B1/B3 dual-frequency tracking of C101/C31 after PRN switch in July 2018
  • High-gain antenna measurements on 27/28 July 2018:
    • C101: B1/B2/B3 signal transmission
    • C104: B1/B3 signal transmission
    • C103: B1/B2/B3 signal transmission

BeiDou-3
SVN
Common Name
Int. Sat. ID
NORAD ID
Sat. Cat. Name
Manuf.
PRN
Notes
C201 BEIDOU-3 MEO-1 2017-069A 43001 BEIDOU-3 M1 CAST C19/C47 Slot B-7; launched 2017/11/05;
PRN C19 used until 2018/06/12
C202 BEIDOU-3 MEO-2 2017-069B 43002 BEIDOU-3 M2 CAST C20 Slot B-8; launched 2017/11/05
C203 BEIDOU-3 MEO-7 2018-003A 43107 BEIDOU 3M3 SECM C27 Slot A-4; launched 2018/01/11
C204 BEIDOU-3 MEO-8 2018-003B 43108 BEIDOU 3M4 SECM C28/C48 Slot A-5; launched 2018/01/11;
PRN C28 used until 2018/06/11
C205 BEIDOU-3 MEO-4 2018-018A 43207 BEIDOU 3M5 CAST C22 Slot B-6; launched 2018/02/12
C206 BEIDOU-3 MEO-3 2018-018B 43208 BEIDOU 3M6 CAST C21 Slot B-5; launched 2018/02/12
C207 BEIDOU-3 MEO-9 2018-029A 43245 BEIDOU 3M7 SECM C29 Slot A-2; launched 2018/03/29
C208 BEIDOU-3 MEO-10 2018-029B 43246 BEIDOU 3M8 SECM C30 Slot A-3; launched 2018/03/29
C209 BEIDOU-3 MEO-5 2018-062A 43581 BEIDOU 3M9 CAST C23 Slot C-7; launched 2018/07/29
C210 BEIDOU-3 MEO-6 2018-062B 43582 BEIDOU 3M10 CAST C24 Slot C-1; launched 2018/07/29
C211 BEIDOU-3 MEO-11 2018-067A 43602 BEIDOU 3M11 SECM C26 Slot C-2; launched 2018/08/24
C212 BEIDOU-3 MEO-12 2018-067B 43603 BEIDOU 3M12 SECM C25 Slot C-8; launched 2018/08/24
C213 BEIDOU-3 MEO-13 2018-072A 43622 BEIDOU 3M13 CAST C32 Slot B-1?; launched 2018/09/19
C214 BEIDOU-3 MEO-14 2018-072B 43623 BEIDOU 3M14 CAST C33 Slot B-3; launched 2018/09/19
C215 BEIDOU-3 MEO-15 2018-???? 43??? BEIDOU 3M15 SECM C?? Slot ?-?; launched 2018/10/15
C214 BEIDOU-3 MEO-16 2018-???? 43??? BEIDOU 3M16 SECM C?? Slot ?-?; launched 2018/10/15

Notes:
  • The numbering of the spacecraft in the satellite catalog differs from the common names.
  • The space vehicle number (SVN) used here follows the satellite catalog number (NORAD ID).
  • Ten out of the 24 BDS-3 MEO satellites are manufactured by the Shanghai Engineering Center for Microsatellites (SECM).
  • Information on BDS-3 is preliminary and might be subject to change.
  • No tracking of PRNs C47 and C48 by IGS receivers so far.


Spacecraft Characteristics


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
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 130 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.

MEOIGSO GEO
Fig. 1 Spacecraft reference system and sensor location for the IGSO/MEO (left) and GEO satellites (right) of the BeiDou-2 regional navigation system. Reproduced from DOI 10.1016/j.asr.2015.06.019 with permission of Elsevier; satellite images courtesy CSNO.

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.
The detailed orientation of the +xIGS and +yIGS-axes for the BeiDOu-2 satellites is defined as shown in the drawings. The GNSS antenna is shifted in +xIGS-direction relative to the center of the front panel, while the LRA is located in the -xIGS/-yIGS-corner. On GEO satellites, the +xIGS-panel holds the C-band telecommunication antenna.

BeiDou-2 GEO/IGSO/MEO
  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 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. Reverse PPP analysis revealed that also C019 does not enter orbit normal mode [9] and that the attitude model of [6] is also valid for this satellite.


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
Parameter
M1S/M2S
M3S
I1S
I2S
Manufacturer CAST SECM SECM CAST
Mass ~1000 kg 848 kg 2800 kg
Body size 2.0 m x 2.5 m x 3.6 m
SRP acceleration 138 nm/s2 86 nm/s2 99 nm/s2
Notes First Chinese H-maser in space


BeiDou-3

Information on the dimension and the attitude law of the BDS-3 MEO satellites manufactured by SECM as well as PCO and LRA offset values are published in [7].

BeiDou-3
Parameter
MEO CAST
MEO SECM
Mass 1030 kg
Body size 2.55 m x 1.01 m x 1.23 m
Solar array size 2 x 1.5 m x 4.7 m

References

[1] ILRS BeiDou (COMPASS) Center of Mass Information
[2] Dilssner F., Springer T., Schönemann E., Enderle W. (2014) Estimation of satellite antenna phase center corrections for BeiDou, IGS Workshop, Pasadena, California, USA
[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
[7] Shanghai Engineering Center for Microsatellites (2018) Satellite Geometry and Attitude Mode of MEO Satellites Developed by SECM, ION GNSS+ 2018
[8] Zhou R., Hu Z., Zhao Q., Li P., Wang W., He C., Cai C., Pan Z. (2018) Elevation-dependent pseudorange variation characteristics analysis for the new-generation BeiDou satellite navigation system, GPS Solututions 22:60, DOI 10.1007/s10291-018-0726-x
[9] Dilssner F. (2018), BeiDou IGSO-7, personal communication, 11 November 2018

Last Updated: 2018/10/16 11:15:19
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