AddAttitude ECIYPR

Adds attitude data based on a time-ordered set of yaw, pitch, roll angles defined with respect to the central body inertial axes (CBI).

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.

Syntax

AddAttitude <ObjectPath> ECIYPR {StartTime} {Sequence} <Yaw> <Pitch> <Roll>

Description

Use the AddAttitude ECIYPR command to modify the attitude of a vehicle using yaw, pitch, and roll attitude data.

The {Sequence} parameter identifies the order of rotations, where the numbers 1, 2 and 3 correspond to the rotations about the central body inertial (CBI) X, Y, and Z axes, respectively. A rotation about the Z axis is considered to a yaw, about the Y axis a pitch and about the X axis a roll. Valid values for {Sequence} are 123, 132, 213, 231, 312, 321.

The angle values, <Yaw> <Pitch> <Roll>, are entered in degrees.

For valid {StartTime} values, see Time Options.

The AddAttitude ECIYPR command is similar to using an external attitude profile, except that you enter the points one at a time using this command.

For two or more inputs of attitude data, you must enter them with increasing times. If you attempt to enter attitude data that is dated prior to existing attitude data, the new entry is ignored. To clear old data, use the SetAttitude ClearData command.

Examples

To add a new line to the STK1 satellite's default attitude file in the Test scenario:

Return message

Group membership

This command belongs to the following group(s):

Vehicles

Version

10