com navigation structure general satellite info ilrs support retroreflector info center of mass site performance info

GPS-35, -36

Center of Mass Information:

GPS XY satellite orientation

The above XY view of the spacecraft illustrates that the relative locations of the GPS satellite center of gravity (CG), the effective laser array center of reflection, and the phase center of the L-band transmitting antenna array. The positive-Z coordinate axis is in the direction of satellite nadir. The coordinates in millimeters of the nominal CG in the body-fixed reference frame are (0, 0, 1011.4). This is really an average position because, over the life of the mission, the CG is expected to move by about 4.6 millimeters in the negative-Z direction, from Z = 1,013.7 millimeters to Z = 1,009.1 millimeters. In the same body-fixed reference frame, the coordinates in millimeters of the antenna array phase center are (279.4, 0, 1,967.9), and the coordinates in millimeters of the effective reflection center for the laser array are (862.6, -524.5, 1,669.8).

GPS YZ satellite orientation

The above YZ view of the spacecraft illustrates that the effective reflection center lies approximately 30 millimeters below the physical surface of the laser array.

The effective reflection points are shown in the following table:

Satellite X offset
Y offset
Z offset
GPS-35 862.58 -524.51 669.5
GPS-36 862.58 -524.51 671.7