Formation Flyer

Formation Flyer is to satisfy a case of maintaining formation and doing so with much less computational cost over the full rendezvous routine. It can handle straight flight and basic turns. It is not designed to come into formation from an arbitrary point, only to maintain. It can handle basic turns, but the results may vary depending on the aggressiveness of the turns. The cost should be significantly less than the full rendezvous.

A Rendezvous Formation flyer is a full 3D formation flying routine. It utilizes proportional navigation strategies (with modification) to lock onto a leader and come into formation with it as directed by the user.

Formation Flyer follows a rendezvous formation and begins at a point when the rendezvous is close to the formation point. The Formation Flyer is able to join up to the exact formation point and handles basic turns by closing in on the leader as best it can. See the picture below for an example route:

The trajectory begins with the leader. It is followed by a Rendezvous formation basic maneuver, which should be used to set the follow parameters and to close in on the formation position. The rendezvous formation takes over after this point.

Position

Field Description
Relative Bearing

The bearing relative to the target that the aircraft will achieve and maintain.

Relative Range

The range from the target that the aircraft will achieve and maintain.

Altitude Split

The altitude difference between the aircraft and the target.

Algorithm Parameters

Table - Algorithm Closed

Option Description
XRange Close Rate Rate at which the plane can tighten up on the narrowed turn radius, measured in the cross range direction.
Initial Close Max Speed Advantage Rate at which any disagreement from the end of the rendezvous formation and the rigid formation point can be closed by Formation Flyer (infinite would mean an immediate jump)
Max Time Step Specifies the maximum interval rate at which the leader will be sampled. Smaller could lead to more memory and cpu usage-large less accurate following.
Min Time Step Minimum leader sampling time. Lower means higher fidelity, higher makes the algorithm faster.

Stop Conditions

Table - Stop Closed

Option Description
Full Mission Follows the leader for the entire mission.
After Time Follows the leader until the given time is reached.
After Fuel State Follows the leader until the fuel state is reached.
After DownRange Follows the leader until the downrange is reached.
After Target Current Procedure Follows the leader until the leader enters into a different procedure.
After Target Current Mission Phase Follows the leader until the leader enters into a different mission phase.
After Target Performance Phase Changes Follows the leader until the leader changes phases (e.g., it transitions from climbing to cruising).
After Target Performance Mode Changes Follows the leader until the leader changes their performance mode (e.g., it transitions from forward flight to VTOL).