agi.foundation.navigation

(agi.foundation.navigation-2023r1.jar)

Class DilutionOfPrecision

java.lang.Object

agi.foundation.navigation.DilutionOfPrecision

public class DilutionOfPrecision
extends Object

A dilution of precision (or DOP), including North (NDOP), East (EDOP), Vertical (VDOP), Horizontal (HDOP), Position (PDOP), Time (TDOP), and the overall Geometric (GDOP). This class also contains static methods to compute DOP.

Constructor Summary

Constructors

Constructor and Description
DilutionOfPrecision() Initializes a new instance with 0.0 for all DOP values.
DilutionOfPrecision(double[][] covarianceMatrix) Initializes a new instance from the specified covariance matrix.
DilutionOfPrecision(double[][] covarianceMatrix, double[][] geometryMatrix) Initializes a new instance from the specified covariance matrix and geometry matrix.

Method Summary

Modifier and Type	Method and Description
static DilutionOfPrecision	compute(Matrix3By3 receiverOrientation, Iterable<Cartesian> satelliteRelativePositions) Computes the Dilution of Precision (DOP).
double[][]	getCovariance() Gets the covariance matrix (H).
double	getGeometric() Gets the geometric dilution of precision (GDOP).
double[][]	getGeometryMatrix() Gets the Geometry matrix (G) after the rotation to the receiver orientation is applied.
boolean	getIsUndefined() Gets a value indicating whether this instance does not have a well-defined DOP.
double	getPosition() Gets the position dilution of precision (PDOP).
double	getTime() Gets the time dilution of precision (TDOP).
double	getValueByType(DilutionOfPrecisionType type) Get the specific value of dilution of precision by its type.
double	getX() Gets the dilution of precision along the X axis.
double	getXY() Gets the dilution of precision in the X-Y plane.
double	getY() Gets the dilution of precision along the Y axis.
double	getZ() Gets the dilution of precision along the Z axis.
void	setIsUndefined(boolean value) Sets a value indicating whether this instance does not have a well-defined DOP.

Methods inherited from class java.lang.Object

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

Constructor Detail

DilutionOfPrecision

public DilutionOfPrecision()

Initializes a new instance with 0.0 for all DOP values.

DilutionOfPrecision

public DilutionOfPrecision(double[][] covarianceMatrix)

Initializes a new instance from the specified covariance matrix. Initializes the GeometryMatrix to all zeroes.

Parameters:

covarianceMatrix - A covariance matrix.

DilutionOfPrecision

public DilutionOfPrecision(double[][] covarianceMatrix,
                           double[][] geometryMatrix)

Initializes a new instance from the specified covariance matrix and geometry matrix. Note that the matrices should already have been rotated by the receiver's orientation.

Parameters:

covarianceMatrix - A covariance (H) matrix.

geometryMatrix - A geometry (G) matrix.

Method Detail

compute

@Nonnull
public static DilutionOfPrecision compute(@Nonnull
                                                    Matrix3By3 receiverOrientation,
                                                    Iterable<Cartesian> satelliteRelativePositions)

Computes the Dilution of Precision (DOP).

This method assumes that all satellites in satelliteRelativePositions are visible to the receiver and should be included in the DOP calculation.

Parameters:

receiverOrientation - The orientation of the receiver relative to the axes in which the satelliteRelativePositions are defined.

satelliteRelativePositions - The relative position of each of the satellites to consider, expressed as a line-of-sight vector from the satellite to the receiver at the time of reception by the receiver. The satellite positions should already account for apparent position due to light-time delay and other effects (if required).

Returns:

The Dilution of Precision (DOP) values for the configuration.

getX

public final double getX()

Gets the dilution of precision along the X axis. When using conventional ENU (East-North-Up) axes, this is the dilution of precision in the East direction, or EDOP.

getY

public final double getY()

Gets the dilution of precision along the Y axis. When using conventional ENU (East-North-Up) axes, this is the dilution of precision in the North direction, or NDOP.

getZ

public final double getZ()

Gets the dilution of precision along the Z axis. When using conventional ENU (East-North-Up) axes, this is the dilution of precision in the Up/Vertical direction, or VDOP.

getXY

public final double getXY()

Gets the dilution of precision in the X-Y plane. When using conventional ENU (East-North-Up) axes, this is the dilution of precision in the horizontal plane, or HDOP.

getPosition

public final double getPosition()

Gets the position dilution of precision (PDOP).

getTime

public final double getTime()

Gets the time dilution of precision (TDOP).

getGeometric

public final double getGeometric()

Gets the geometric dilution of precision (GDOP).

getIsUndefined

public final boolean getIsUndefined()

Gets a value indicating whether this instance does not have a well-defined DOP. This may happen when less than 4 satellites are used to create the DOP for example.

setIsUndefined

public final void setIsUndefined(boolean value)

Sets a value indicating whether this instance does not have a well-defined DOP. This may happen when less than 4 satellites are used to create the DOP for example.

getValueByType

public final double getValueByType(@Nonnull
                                   DilutionOfPrecisionType type)

Get the specific value of dilution of precision by its type.

Parameters:

type - The type of dilution of precision.

Returns:

Returns the property corresponding to the given type of dilution of precision.

getCovariance

public final double[][] getCovariance()

Gets the covariance matrix (H).

Note that internally, we do not calculate to full covariance matrix to speed calculations. If this method is called, we will return the full covariance matrix, making a separate call to calculate it if necessary.

Returns:

The covariance matrix.

getGeometryMatrix

public final double[][] getGeometryMatrix()

Gets the Geometry matrix (G) after the rotation to the receiver orientation is applied.

Returns:

The geometry matrix.