Package org.orekit.files.sp3

Class SP3CoordinateHermiteInterpolator

java.lang.Object

org.orekit.time.AbstractTimeInterpolator<SP3Coordinate>

org.orekit.files.sp3.SP3CoordinateHermiteInterpolator

All Implemented Interfaces:

TimeInterpolator<SP3Coordinate>

public class SP3CoordinateHermiteInterpolator
extends AbstractTimeInterpolator<SP3Coordinate>

Interpolator for SP3 coordinates.

As this implementation of interpolation is polynomial, it should be used only with small number of interpolation points (about 10-20 points) in order to avoid Runge's phenomenon and numerical problems (including NaN appearing).

If some clock or clock rate are present in the SP3 files as default values (999999.999999), then they are replaced by Double.NaN during parsing, so the interpolation will exhibit NaNs, but the positions will be properly interpolated.

Since:

12.0

Author:

Luc Maisonobe

See Also:

• HermiteInterpolator
• SP3Coordinate

Nested Class Summary

Nested classes/interfaces inherited from class org.orekit.time.AbstractTimeInterpolator

AbstractTimeInterpolator.InterpolationData

Field Summary

Fields inherited from class org.orekit.time.AbstractTimeInterpolator

DEFAULT_EXTRAPOLATION_THRESHOLD_SEC, DEFAULT_INTERPOLATION_POINTS

Constructor Summary

Constructors

Constructor	Description
SP3CoordinateHermiteInterpolator(int interpolationPoints, double extrapolationThreshold, boolean useRates)	Constructor.

Method Summary

Modifier and Type	Method	Description
protected SP3Coordinate	interpolate(AbstractTimeInterpolator<SP3Coordinate>.InterpolationData interpolationData)	Interpolate instance from given interpolation data.

Methods inherited from class org.orekit.time.AbstractTimeInterpolator

addOptionalSubInterpolatorIfDefined, checkInterpolatorCompatibilityWithSampleSize, getCentralDate, getCentralDate, getExtrapolationThreshold, getInternalNbInterpolationPoints, getNbInterpolationPoints, getSubInterpolators, getTimeParameter, interpolate, interpolate

Methods inherited from class java.lang.Object

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

Constructor Details

SP3CoordinateHermiteInterpolator

public SP3CoordinateHermiteInterpolator(int interpolationPoints,
 double extrapolationThreshold,
 boolean useRates)

Constructor.

As this implementation of interpolation is polynomial, it should be used only with small number of interpolation points (about 10-20 points) in order to avoid Runge's phenomenon and numerical problems (including NaN appearing).

Parameters:

interpolationPoints - number of interpolation points

extrapolationThreshold - extrapolation threshold beyond which the propagation will fail

useRates - if true, use velocity and clock rates for interpolation

Method Details

interpolate

protected SP3Coordinate interpolate(AbstractTimeInterpolator<SP3Coordinate>.InterpolationData interpolationData)

Interpolate instance from given interpolation data.

The interpolated instance is created by polynomial Hermite interpolation ensuring velocity remains the exact derivative of position.

Note that even if first time derivatives (velocities) from sample can be ignored, the interpolated instance always includes interpolated derivatives. This feature can be used explicitly to compute these derivatives when it would be too complex to compute them from an analytical formula: just compute a few sample points from the explicit formula and set the derivatives to zero in these sample points, then use interpolation to add derivatives consistent with the positions.

Specified by:

interpolate in class AbstractTimeInterpolator<SP3Coordinate>

Parameters:

interpolationData - interpolation data

Returns:

interpolated instance from given interpolation data.