Point Fixed
Control fixed sensor pointing for a specified sensor instance
Syntax
Point <SensorObjectPath> Fixed {OrientMethod} <MethodData>
Related commands
- Point 3DModel
- Point AlongVector
- Point External
- Point FixedInRef
- Point GrazingAlt
- Point Schedule
- Point Spinning
- Point Targeted
Description
The Point Fixed command controls fixed sensor pointing for a specified sensor instance. Fixed sensor pointing allows you to specify the orientation of the sensor in the parent object's body coordinate frame. It always points in the same direction relative to the parent.
While the sensor never moves relative to the parent object, the motion of the parent object affects the direction in which the sensor is pointed in inertial space. Therefore, you should understand the behavior of the parent object so that you can accurately determine the sensor's behavior.
<MethodData> for Fixed sensor pointing is dependent on the {OrientMethod} used. Valid values for {OrientMethod} and their associated <MethodData> are as follows:
| {OrientMethod} | <MethodData> | Description |
|---|---|---|
| AzEl | <Azimuth> <Elevation> [{AboutBoresight}] | {AboutBoresight} can be Hold or Rotate. |
| Euler | <Sequence> <Rot1> <Rot2> <Rot3> | <Sequence> can be 121, 123, 131, 132, 212, 213, 231, 232, 312, 313, 321, 323, where 1 is the rotation about the Z axis, 2 is the rotation about the Y axis and 3 is the rotation about the Z axis. |
| YPR | <Sequence> <Yaw> <Pitch> <Roll> | <Sequence> can be 123, 132, 213, 231, 312, or 321, where 1 is the rotation about the reference X axis, 2 is the rotation about the reference Y axis, and 3 is the rotation about the reference Z axis. The reference axes are the body-fixed axes of the parent object.
Similarly to Euler angles, YPR angles specify attitude using three rotations in a chosen sequence: the rotation about the reference X axis is called roll (R), the rotation about the reference Y axis is called pitch (P), and the rotation about the reference Z axis is called yaw (Y). Sequences are identified using either numbers (1 is the X axis, 2 is the Y axis, 3 is the Z axis) or letters (R is the X axis, P is the Y axis, Y is the Z axis). Unlike Euler angles, the rotations are not made about axes defined by an earlier rotation. Instead, each rotation is made about the reference system's axes. In YPR angles, the names yaw, pitch, and roll do NOT refer to the angles normally used in aviation; the terms yaw, pitch, and roll in aviation refer to 321 Euler angles. |
| Quaternion | <q1> <q2> <q3> <q4> | N/A |
All angle values should be entered in degrees.
Examples
To point the Shuttle's Horizon sensor to 80 degrees azimuth at an elevation of 45 degrees:
Return message
Group membership
This command belongs to the following group(s):
Version
4.0