SLR Center-of-Mass (CoM) Measurement Correction Information
The following table shows the components of the satellite body-fixed offset of the SLR array phase center (LRA offset: the blue vector in this SLR center of mass correction Concept Diagram) in the satellite's coordinate system. The total SLR center of mass correction (red vector) should be computed by using the LRA offset vector and the satellite Center of Mass (CoM) offset vector (green vector). The CoM offset may vary slightly with time, depending upon the use of propellant for satellite momentum dumps, satellite orbit maneuvers, antenna orientation changes, et cetera. The "location" of the LRA phase center may also vary; it is the locus of points from which the return came as a result of a particular satellite-station geometry and station characteristics (single or multiple photon, receiver type, et cetera).
| Satellite | Size of Array | Number of Reflectors | Body Fixed Coordinates of Array Phase Center (mm) |
Spacecraft Coordinate Definition |
CoM Correction (mm) and details |
|---|---|---|---|---|---|
| ADEOS-1 | 35.6 cm edge hollow cube | 1 | ? | ? | |
| ADEOS-2 | 16 cm diameter hemisphere | 9 | (+5000, +1050, +500) | Y-axis anti-parallel with velocity, Z-axis away from nadir |
|
| Ajisai | 214 cm diameter sphere | 1,436 | 1028 | sphere: radius of phase center of each cube |
details |
| Beacon-C | Pyramidal array on nadir face |
160 | ? | phase center of each cube | |
| BLITS | 85.16 mm diameter sphere | 1 | (0, 0, 0) | origin at center of the single sphere | details |
| CHAMP | 5cm diameter, 45 deg pyramid |
4 | (0, 0, 250) | Z-axis towards nadir | details |
| CryoSat-2 | 11.4 cm diameter, 0 or 57.5 deg pyramid | 7 | (1808.5, -935.0, -450.0) plus 15-25 mm for LRA details |
X-axis 6° from the flight direction (nose-down), negative-Z-axis 6° from the nadir, Yaw steering (normal operation) applied so that Y-axis orthogonal to the satellite ground track |
details |
| Envisat | 20 cm diameter hemisphere | 9 | (-1058, +1359, -1183) | X-axis direction of satellite pitch, Z-axis away from nadir |
details |
| ERS-2 | 20 cm diameter hemisphere | 9 | (1000, -710, -1010) | X-axis direction of satellite pitch, Z-axis away from nadir |
|
| Etalon-1, -2 | 129.4 cm diameter sphere | 2,134 | 614 | sphere: radius of phase center of each cube |
details |
| Galileo-101 | 33 mm diameter, 23.3 mm height | 84 | (1092, -34, 621) | X-axis negative to hemisphere containing the Sun, Y-axis along solar panel, Z-axis towards nadir |
details |
| Galileo-102 | 33 mm diameter, 23.3 mm height | 84 | (1093, -34, 623) | X-axis negative to hemisphere containing the Sun, Y-axis along solar panel, Z-axis towards nadir |
details |
| GFO-1 | 16 cm diameter hemisphere | 9 | (+182, +753, +599) | Y-axis anti-parallel with velocity, Z-axis away from nadir |
details |
| GFZ-1 | 20 cm diameter sphere | 60 | sphere: radius of phase center of each cube |
58 +/- 2 | |
| GIOVE-A | 30x40 cm planar array | 76 | (-828, -655, +688) | X-axis negative to hemisphere containing the Sun, Y-axis along solar panel, Z-axis towards nadir, attitude details |
details |
| GIOVE-B | 30x30 cm planar array | 67 | (-804.3, +294.1, +1330.1) | X-axis negative to hemisphere containing the Sun, Y-axis along solar panel, Z-axis towards nadir, attitude details |
details |
| GLONASS | 120x120 cm planar array | 396 | (-1542, 0, 0) | X-axis away from nadir, Y-axis negative to hemisphere containing the Sun, Z-axis along solar panel |
|
| GLONASS | 66x66 cm planar array | 132 | (-1555, 0, 0) | X-axis away from nadir, Y-axis negative to hemisphere containing the Sun, Z-axis along solar panel |
|
| GLONASS | 66x66 cm planar array | 124 | (-1522, 0, 0) | X-axis away from nadir, Y-axis negative to hemisphere containing the Sun, Z-axis along solar panel |
|
| GLONASS-95, -99, -100, -102, -109, -115 | 30x50 cm planar array | 112 | (-1874, -137, +3) | X-axis away from nadir, Y-axis negative to hemisphere containing the Sun, Z-axis along solar panel |
details |
| GLONASS-125 | annulus array | 123 | details |
||
| GPS-35 | 23.9x19.4 cm planar array | 32 | (862.6, -524.5, 669.5) | X-axis positive to hemisphere containing the Sun, |
details |
| GPS-36 | 23.9x19.4 cm planar array | 32 | (862.6, -524.5, 671.7) | X-axis positive to hemisphere containing the Sun, Y-axis along solar panel, Z-axis towards nadir |
details |
| GRACE-A, -B | 10 cm diameter, 45 deg pyramid |
4 | (-600, -327.5, 217.8) | X-axis is the 'front', Z-axis towards nadir, Y-axis completes the orthogonal system | details |
| Gravity Probe B | Open hemisphere | 9 | (0, 0, -1820) | +Z-axis towards RA 343.26deg, DEC 16.84deg | details |
| ICESat | 16 cm diameter hemisphere | 9 | (-1045, -4, 280) (plus 4.5 cm for the LRA) |
X-axis towards satellite zenith, Y-axis along solar panel |
details |
| Jason-1 | hemisphere | 9 | (1171, 598, 6828) (-49 mm for the LRA) | X-axis in direction of velocity, Z-axis towards nadir |
details |
| Jason-2 | hemisphere | 9 | (1194, 598, 6838) (-49 mm for the LRA) | X-axis in direction of velocity, Z-axis towards nadir |
details |
| LAGEOS-1 | 60 cm diameter sphere | 426 | 258 | sphere: radius of phase center of each cube |
details |
| LAGEOS-2 | 60 cm diameter sphere | 426 | 258 | sphere: radius of phase center of each cube |
details |
| LARES | 36.4 cm diameter sphere | 92 | 137.1 | sphere: radius of phase center of each cube | details |
| Larets | 20 cm diameter sphere | 60 | 56.2 | sphere: radius of phase center of each cube |
details |
| LRE | quasi-spherical, 47x51 cm diameter |
126 | sphere: radius of phase center of each cube |
210 |
|
| Meteor-3M | spherical ball, 6 cm diameter |
1 | (+113, +475.7, +2101.5) | ? | details |
| SARAL | hemisphere | 9 | (4735, 0, -940) (-43.4mm for the LRA | X-axis is nadir pointing, Z-axis opposite to cross track | |
| Starlette | 24 cm diameter sphere | 60 | sphere: radius of phase center of each cube |
75 details |
|
| Stella | 24 cm diameter sphere | 60 | sphere: radius of phase center of each cube |
75 | |
| TOPEX/Poseidon | 150 cm diameter annulus | 192 | (+1079, +418, +827) | Center of annulus. X-axis in direction of velocity, Z-axis towards nadir |
details |
| WESTPAC | 24 cm diameter sphere | 60 | 63.4 | Radius of satellite through front face of the cubes (91mm) | details |
