Autopilot - Vertical Plane

The Autopilot - Vertical Plane strategy is a vertical plane strategy in which the aircraft uses a control system to maintain a specified altitude, altitude change, altitude rate, or flight path angle, or to fly a ballistic flight path.

Altitude

Select a method for defining the altitude or change in altitude of the aircraft during the maneuver from the drop-down menu, and define any subordinate properties that are displayed for that method.

Table - Altitude Modes

Mode	Description
Hold Initial Altitude	The aircraft will attempt to hold the altitude at which it began the maneuver. Select whether to control the altitude rate or the flight path angle at which the aircraft will adjust its altitude with respect to the goal.
Specify Altitude	The aircraft will attempt to maintain a specified altitude above the current ground reference. The absolute altitude that you want the aircraft to achieve and then select whether to control the altitude rate or the flight path angle at which the aircraft will adjust its altitude with respect to the goal.
Specify Altitude Change	The aircraft will attempt to achieve a specified altitude relative to the aircraft's altitude at the beginning of the maneuver. The relative altitude change that you want the aircraft to achieve and then select whether to control the altitude rate or the flight path angle at which the aircraft will adjust its altitude with respect to the goal.
Specify Altitude Rate	The aircraft will attempt to maintain a specified rate of altitude change during the maneuver.
Hold Initial Altitude Rate	The aircraft will attempt to hold the altitude rate at which it began the maneuver.
Specify Wind Frame Flight Path Angle	The aircraft will attempt to maintain a specified flight path angle. The exact angle achieved may be influenced by wind effects if you are applying them to the mission.
Hold Initial Wind Frame Flight Path Angle	The aircraft will attempt to hold the flight path angle at which it began the maneuver. The exact angle achieved may be influenced by wind effects if you are applying them to the mission.
Ballistic Flight Path	The aircraft will fly a ballistic flight path between the beginning and end of the aircraft's maneuver in the horizontal plane.

Control Limits

Select a method to define the vertical control limits of the aircraft during guidance maneuvering. Select Use Accel Perf Model to constrain the pitch rate using the Push Over G value of the current Acceleration performance model or Specify Max Pitch Rate to override the performance model with a specified maximum flight path angle rate value. The pitch rate applies to both Flight Path Angle (FPA) and Angle of Attack The angle between the body X axis and the projection of the velocity vector onto the body XZ plane. The velocity vector is the velocity of the object as observed in the object's central body fixed coordinate system. (AOA) rate limits. In STK's Aviator capability, "pitch" is the sum of FPA and AOA, so you may see pitch rates beyond the specified limit.

Stop when conditions are met

When enabled, Aviator stops when the specified value is reached. Aviator stops when the conditions are met regardless of what is set in the Basic Stopping Conditions, unless the Basic Stopping Conditions are met first.

The Ballistic Flight Path mode is not available for this option.

Fly Ballistic when performance is insufficient

Select this check box to have the vehicle fly a ballistic bath if the performance is insufficient.

Damping Ratio

Use the Damping Ratio to control the dynamic response of the control law. A ratio that is less than one will result in varying degrees of oscillation in the aircraft's flight path, while a ratio that is greater that one will result in slower, smoother transitions along the aircraft's flight path. By default the ratio is set to a conservative, normal value.

Airspeed

Select a method to define the aircraft's airspeed for the maneuver from the drop-down menu and define any related properties for it.

The Min Speed Limits and Max Speed Limits properties control the behavior of STK's Aviator capability if the aircraft violates the minimum or maximum airspeed during the maneuver; select Constrain if Violated to force the aircraft to obey the limit and continue the maneuver (possibly violating physical laws), Stop if Violated to stop the maneuver at the minimum or maximum airspeed, Error if Violated to make the procedure invalid, or Ignore Limits to ignore the speed limits.