org.orekit.estimation.iod

Class IodLaplace

java.lang.Object

org.orekit.estimation.iod.IodLaplace

public class IodLaplace
extends Object

Laplace angles-only initial orbit determination, assuming Keplerian motion. An orbit is determined from three angular observations from the same site. Reference: Bate, R., Mueller, D. D., & White, J. E. (1971). Fundamentals of astrodynamics. New York: Dover Publications.

Since:

10.1

Author:

Shiva Iyer

Constructor Summary

Constructors

Constructor and Description
IodLaplace(double mu) Constructor.

Method Summary

Modifier and Type	Method and Description
CartesianOrbit	estimate(Frame frame, PVCoordinates obsPva, AbsoluteDate obsDate1, Vector3D los1, AbsoluteDate obsDate2, Vector3D los2, AbsoluteDate obsDate3, Vector3D los3) Estimate orbit from three line of sight angles from the same location.
CartesianOrbit	estimate(Frame frame, PVCoordinates obsPva, AngularRaDec raDec1, AngularRaDec raDec2, AngularRaDec raDec3) Estimate the orbit from three angular observations at the same location.
static Vector3D	lineOfSight(AngularRaDec raDec) Calculate the line of sight vector from an AngularRaDec measurement.
static Vector3D	lineOfSight(double alpha, double delta) Calculates the line of sight vector.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

IodLaplace

public IodLaplace(double mu)

Constructor.

Parameters:

mu - gravitational constant

Method Detail

estimate

public CartesianOrbit estimate(Frame frame,
                               PVCoordinates obsPva,
                               AngularRaDec raDec1,
                               AngularRaDec raDec2,
                               AngularRaDec raDec3)

Estimate the orbit from three angular observations at the same location.

Parameters:

frame - inertial frame for observer coordinates and orbit estimate

obsPva - Observer coordinates at time of raDec2

raDec1 - first angular observation

raDec2 - second angular observation

raDec3 - third angular observation

Returns:

estimate of the orbit at the central date obsDate2 or null if no estimate is possible with the given data

Since:

11.0

estimate

public CartesianOrbit estimate(Frame frame,
                               PVCoordinates obsPva,
                               AbsoluteDate obsDate1,
                               Vector3D los1,
                               AbsoluteDate obsDate2,
                               Vector3D los2,
                               AbsoluteDate obsDate3,
                               Vector3D los3)

Estimate orbit from three line of sight angles from the same location.

Parameters:

frame - inertial frame for observer coordinates and orbit estimate

obsPva - Observer coordinates at time obsDate2

obsDate1 - date of observation 1

los1 - line of sight unit vector 1

obsDate2 - date of observation 2

los2 - line of sight unit vector 2

obsDate3 - date of observation 3

los3 - line of sight unit vector 3

Returns:

estimate of the orbit at the central date obsDate2 or null if no estimate is possible with the given data

lineOfSight

public static Vector3D lineOfSight(double alpha,
                                   double delta)

Calculates the line of sight vector.

Parameters:

alpha - right ascension angle, in radians

delta - declination angle, in radians

Returns:

the line of sight vector

Since:

11.0

lineOfSight

public static Vector3D lineOfSight(AngularRaDec raDec)

Calculate the line of sight vector from an AngularRaDec measurement.

Parameters:

raDec - measurement

Returns:

the line of sight vector

Since:

11.0