Req. 5.4.2.3: "Celestial Coordinate System"
The FSW shall report celestial coordinates in the J2000 inertial coordinate system, using right ascension (RA) and declination (DEC).
Basis (help)
[1] (3.1.1.6.1-2, 3.3.1.6.1-2), [2] (3.2.1.2)
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1: "Mission System Spec." (NASA 433-SPEC-0001)
3.1.1.6.1: "Inertial Coordinate System"
GLAST shall use the J2000 inertial coordinate system.
3.1.1.6.2: "Right Ascension and Declination"
Right Ascension (RA) and Declination (DEC) shall be used as a standard means of receiving and communicating pointing directions.
3.3.1.6.1: "Inertial"
3.3.1.6.1.1: "J2000 System"
The observatory shall use the J2000 inertial coordinate system.
3.3.1.6.1.2: "Right Ascension and Declination"
RA and DEC shall be used as a standard means of receiving and communicating pointing directions.
3.3.1.6.2: "Body Fixed"
The observatory shall use a right-handed coordinate system fixed in the observatory body, as shown in Figure 3-1. The origin of the body-fixed coordinate system shall lie in the separation plane of the launch vehicle Payload Attachment Fitting (PAF). The Z-axis shall be collinear with the geometrical centerline of the observatory. The +Z direction shall lie along the center of the LAT field of view. The Y-axis shall be parallel to the solar array drive axes. The -X axis shall be the anti-sun side. The +Y-axis shall be the cross-product of the +Z-axis and the +X-axis. The terms Roll axis, Pitch axis, and Yaw axis shall refer to the X, Y, and Z observatory axes, respectively.
3.2.1.2: "Celestial Coordinates"
The Observatory shall use celestial coordinates relative to the J2000 coordinate frame. Pointing commands to the Observatory and pointing directions reported by the Observatory shall be by Right Ascension (RA) and Declination (Dec) in J2000 coordinates.
Context (help)
