TriggerAngleTargeting Class Reference

Determine the burn required for a specific trigger angle for rendezvous. More...

Static Public Member Functions
static Vector3d	ComputeBurnOld (double z0, double omega, double thetaDeg, double xf, Vector3d Omega)
static double	ComputeAngleRadians (double z0, double thetaRad, double xf)
static double	ComputeBurnForAngle (OrbitUniversal shipOrbit, OrbitUniversal targetOrbit, double angleRad)
	Given a ship and a target in coplanar circular orbits and a desired trigger angle, determine the magnitude of the burn required. The routine does not use the current position of the ship and target.

Static Public Attributes
static double	triggerAngle

Detailed Description

Determine the burn required for a specific trigger angle for rendezvous.

Apollo used a rendezvous burn that was directed along the line of sight from the ship to the target. The trigger angle was the angle above the ship direction of flight to the target.

This burn requires that the ship and target be in co-elliptic orbits (i.e. same argument of perigee and inclination).

The algorithm is from: Trigger Angle Targeting for Orbital Rendezvous, Woffinden, Rose and Geller (2008) Journal of the Astronautical Sciences Vol 56. No 4 pp.495-513.

The algorithm uses relative co-ordinates in which the target is at the origin in x, y, z. It is suitable for cases where the differences in altitude are small compared to the radius of the orbits.

There is a window of possible trigger angles from approx. 26.7 degrees to 125.2. In some cases there are two possible burns that result in different transfer phase angles (see Fig 3 in the paper).

Member Function Documentation

ComputeBurnForAngle()

static double TriggerAngleTargeting.ComputeBurnForAngle ( OrbitUniversal  shipOrbit, OrbitUniversal  targetOrbit, double  angleRad  )

static

Given a ship and a target in coplanar circular orbits and a desired trigger angle, determine the magnitude of the burn required. The routine does not use the current position of the ship and target.

This follows the development in "Practical Astrodynamics Vol1" A. de laco Veris. p659-667

The algorithm iterates to find a deltaV with the required precision (delta theta) of the rendezvous. This is set to 1E-4 radians by default.

NOT DEBUGGED!!!!

Parameters

ship
target
planet
angle

Returns

ComputeBurnOld()

static Vector3d TriggerAngleTargeting.ComputeBurnOld ( double  z0, double  omega, double  thetaDeg, double  xf, Vector3d  Omega  )

static

Parameters

ship
target
planet
z0	Difference in Altitide
theta	Orbital transfer angle
xf	X offset to target at closest approach (0 to meet target)

Returns

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The documentation for this class was generated from the following file:

• C:/Users/musgr/Documents/Unity/gravityengine/Assets/GravityEngine/Scripts/Orbits/Transfers/RelativeMotion/TriggerAngleTargeting.cs