Change Attitude

Script Type: WsfChangeAttitude

event change_attitude
   Common Maneuver Commands …
   orientation ...
end_event

Change the orientation type to which the attitude controller orients the parent platform.

orientation <orientation-type>
orientation <entity-orientation-type> <platform-name>
orientation <geo-point-orientation-type> <geo-point-name>

Specify how the platform is to be oriented.

All orientation types describe a pointing alignment and pointing constraint for two of the three ECS axes. Depending on the type, either:

  • the ECS z-axis points in the direction of the fixed orientation, while the ECS x-axis points in the direction of the constraint (in the plane of the constraint direction and z-axis) or

  • the ECS x-axis points in the direction of the fixed orientation, while the ECS z-axis points in the direction of the constraint (in the plane of the constraint direction and x-axis).

Note

For example, nadir_with_eci_velocity_constraint means that the ECS z-axis points to center of the Earth (nadir), while the ECS x-axis points in the direction of the velocity vector, constrained to the plane of the velocity vector and nadir.

Standard orientation types are the following:

  • nadir_with_eci_velocity_constraint : Z-axis nadir orientation with ECI x-axis velocity constraint

  • nadir_with_ecef_velocity_constraint : Z-axis nadir orientation with ECEF (WCS) x-axis velocity constraint

  • nadir_with_solar_constraint : Z-axis Nadir orientation with solar constraint

  • solar_with_nadir_constraint : Z-axis Solar orientation with nadir constraint

  • eci_velocity_with_nadir_constraint : X-axis ECI velocity orientation with z-axis nadir constraint

  • eci_velocity_with_solar_constraint : X-axis ECI velocity orientation with z-axis solar constraint

  • none : No orientation / constraint is provided. Orientation changes must be input by the user.

Entity orientation types are the following:

  • entity_with_solar_constraint : X-axis entity orientation with z-axis solar constraint

  • entity_with_nadir_constraint : X-axis entity orientation with z-axis nadir constraint

  • entity_with_orbit_plane_constraint : X-axis entity orientation with z-axis orbit plane constraint

Note

Given the entity pointing alignment vector \vec{p}, the orbit plane constraint is defined to be (\vec{r}\times\vec{v})\times\vec{p}, where \vec{r} is the inertial location vector and \vec{v} is the inertial velocity vector.

Note

The <platform-name> must be the name of a pre-defined platform in the current scenario.

The geo-point orientation type is the following:

  • point_with_orbit_plane_constraint : X-axis geo_point orientation with z-axis orbit plane constraint.

Note

Given the geo-point pointing alignment vector \vec{p}, the orbit plane constraint is defined to be (\vec{r}\times\vec{v})\times\vec{p}, where \vec{r} is the inertial location vector and \vec{v} is the inertial velocity vector.

Note

The <geo-point-name> must be the name of a geo_point defined on a platform.

Default nadir_with_eci_velocity_constraint

Note

Scripted orientation methods and attitude change event can be used to change the platform’s attitude during the course of a simulation.

Note

All orientation types are with respect to the platform’s ECS coordinate frame, which is right-handed.

swap_axes

Swap the pointing and constraint axes for the currently specified orientation.

Note

For example, if the nadir_with_eci_velocity_constraint orientation is specified, followed by swap_axes, the x-axis will point at the nadir, and the z-axis will point in the direction of the velocity constraint.