fr.cnes.sirius.patrius.fieldsofview

Class AzimuthElevationField

java.lang.Object

fr.cnes.sirius.patrius.fieldsofview.AzimuthElevationField

All Implemented Interfaces:

IFieldOfView, Serializable

public class AzimuthElevationField
extends Object
implements IFieldOfView

Field of view defined by an azimuth-elevation mask : the algorithms are from the Orekit GroundMaskElevationDetector detector. The mask is defined by an azimuth-elevation array : the vertical is the Z axis of the local frame, the angle between the local north and the x axis must be given at construction.
The angular distance to the field limit is not the exact shortest distance: it is the exact angular distance on the local meridian (difference of elevation of the target and the linear interpolated local elevation). Concerning the field of view, the limit between two consecutive points is NOT a great circle (i.e. planar) limit: it is linear in azimuth-elevation. The fields with planar limits are the Rectangle or Pyramidal fields.

Since:

1.2

Version:

$Id$

Author:

Thomas Trapier

See Also:

Serialized Form

Concurrency :

immutable

Constructor Summary

Constructors

Constructor and Description
AzimuthElevationField(double[][] azimElevMask, double frameOrientation, String fovName) Constructor for the azimuth - elevation mask

Method Summary

Modifier and Type	Method and Description
double	getAngularDistance(Vector3D point) Computes the angular distance between a vector and the border of the field.
AzimuthElevationCalculator	getAzimuthElevationCalculator() Returns the Azimuth Elevation Calculator.
double	getElevation(double azimuth) Get the Mask interpolated Elevation for a given Azimuth : this algorithm is from the orekit's GroundMaskElevationDetector
String	getName()
boolean	isInTheField(Vector3D point)
double	linear(double x, double xa, double xb, double ya, double yb) Linear interpolation for given point x between (xa, ya) and (xb, yb).

Methods inherited from class java.lang.Object

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

Constructor Detail

AzimuthElevationField

public AzimuthElevationField(double[][] azimElevMask,
                             double frameOrientation,
                             String fovName)

Constructor for the azimuth - elevation mask

Parameters:

azimElevMask - the azimuth (defined from North, clockwise, rad) - elevation mask (rad)

frameOrientation - Oriented angle (trigowise, radian) between the local North and the Frame's x axis
Example :
If "Reference Azimuth" is aligned with the local North of a local topocentric frame
then a frameOrientation of -0.785 (=> -45°) means that the x axis of the Frame points to North-East

fovName - the name of the field

Method Detail

getAngularDistance

public double getAngularDistance(Vector3D point)

Computes the angular distance between a vector and the border of the field. The result is positive if the direction is in the field, negative otherwise. This value is approximative, mostly when the mask has great elevation variations, but its sign is right.

Specified by:

getAngularDistance in interface IFieldOfView

Parameters:

point - Point Cartesian coordinates

Returns:

the angular distance

isInTheField

public boolean isInTheField(Vector3D point)

Specified by:

isInTheField in interface IFieldOfView

Parameters:

point - a direction vector (expressed in the topocentric coordinate system of the object)

Returns:

true if the direction is in the field

getName

public String getName()

Specified by:

getName in interface IFieldOfView

Returns:

the name of the field

getElevation

public double getElevation(double azimuth)

Get the Mask interpolated Elevation for a given Azimuth : this algorithm is from the orekit's GroundMaskElevationDetector

Parameters:

azimuth - azimuth (counted clockwise) (rad)

Returns:

elevation angle (rad)

linear

public double linear(double x,
                     double xa,
                     double xb,
                     double ya,
                     double yb)

Linear interpolation for given point x between (xa, ya) and (xb, yb).

Parameters:

x - x

xa - xa

xb - xb

ya - ya

yb - yb

Returns:

linear interpolation for given point x between (xa, ya) and (xb, yb)

getAzimuthElevationCalculator

public AzimuthElevationCalculator getAzimuthElevationCalculator()

Returns the Azimuth Elevation Calculator.

Returns:

the Azimuth Elevation Calculator