org.orekit.propagation.analytical.tle

Class FieldTLE<T extends CalculusFieldElement<T>>

java.lang.Object

org.orekit.propagation.analytical.tle.FieldTLE<T>

All Implemented Interfaces:

Serializable, FieldTimeStamped<T>

public class FieldTLE<T extends CalculusFieldElement<T>>
extends Object
implements FieldTimeStamped<T>, Serializable

This class is a container for a single set of TLE data.

TLE sets can be built either by providing directly the two lines, in which case parsing is performed internally or by providing the already parsed elements.

TLE are not transparently convertible to Orbit instances. They are significant only with respect to their dedicated propagator, which also computes position and velocity coordinates. Any attempt to directly use orbital parameters like eccentricity, inclination, etc. without any reference to the TLE propagator is prone to errors.

More information on the TLE format can be found on the CelesTrak website.

Since:

11.0

Author:

Fabien Maussion, Luc Maisonobe, Thomas Paulet (field translation)

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static String	B_STAR Parameter name for B* coefficient.
static int	DEFAULT Identifier for default type of ephemeris (SGP4/SDP4).
static int	SDP4 Identifier for SDP4 type of ephemeris.
static int	SDP8 Identifier for SDP8 type of ephemeris.
static int	SGP Identifier for SGP type of ephemeris.
static int	SGP4 Identifier for SGP4 type of ephemeris.
static int	SGP8 Identifier for SGP8 type of ephemeris.

Constructor Summary

Constructors

Constructor and Description
FieldTLE(Field<T> field, String line1, String line2) Simple constructor from unparsed two lines.
FieldTLE(Field<T> field, String line1, String line2, TimeScale utc) Simple constructor from unparsed two lines using the given time scale as UTC.
FieldTLE(int satelliteNumber, char classification, int launchYear, int launchNumber, String launchPiece, int ephemerisType, int elementNumber, FieldAbsoluteDate<T> epoch, T meanMotion, T meanMotionFirstDerivative, T meanMotionSecondDerivative, T e, T i, T pa, T raan, T meanAnomaly, int revolutionNumberAtEpoch, double bStar) Simple constructor from already parsed elements.
FieldTLE(int satelliteNumber, char classification, int launchYear, int launchNumber, String launchPiece, int ephemerisType, int elementNumber, FieldAbsoluteDate<T> epoch, T meanMotion, T meanMotionFirstDerivative, T meanMotionSecondDerivative, T e, T i, T pa, T raan, T meanAnomaly, int revolutionNumberAtEpoch, double bStar, TimeScale utc) Simple constructor from already parsed elements using the given time scale as UTC.

Method Summary

Modifier and Type	Method and Description
boolean	equals(Object o) Check if this tle equals the provided tle.
double	getBStar() Get the ballistic coefficient.
char	getClassification() Get the classification.
FieldAbsoluteDate<T>	getDate() Get the TLE current date.
T	getE() Get the eccentricity.
int	getElementNumber() Get the element number.
int	getEphemerisType() Get the type of ephemeris.
T	getI() Get the inclination.
int	getLaunchNumber() Get the launch number.
String	getLaunchPiece() Get the launch piece.
int	getLaunchYear() Get the launch year.
String	getLine1() Get the first line.
String	getLine2() Get the second line.
T	getMeanAnomaly() Get the mean anomaly.
T	getMeanMotion() Get the mean motion.
T	getMeanMotionFirstDerivative() Get the mean motion first derivative.
T	getMeanMotionSecondDerivative() Get the mean motion second derivative.
T[]	getParameters(Field<T> field) Get model parameters.
List<ParameterDriver>	getParametersDrivers() Get the drivers for TLE propagation SGP4 and SDP4.
T	getPerigeeArgument() Get the argument of perigee.
T	getRaan() Get Right Ascension of the Ascending node.
int	getRevolutionNumberAtEpoch() Get the revolution number.
int	getSatelliteNumber() Get the satellite id.
int	hashCode() Get a hashcode for this tle.
static boolean	isFormatOK(String line1, String line2) Check the lines format validity.
static <T extends CalculusFieldElement<T>> FieldTLE<T>	stateToTLE(FieldSpacecraftState<T> state, FieldTLE<T> templateTLE) Convert Spacecraft State into TLE.
static <T extends CalculusFieldElement<T>> FieldTLE<T>	stateToTLE(FieldSpacecraftState<T> state, FieldTLE<T> templateTLE, TimeScale utc, Frame teme) Convert Spacecraft State into TLE.
static <T extends CalculusFieldElement<T>> FieldTLE<T>	stateToTLE(FieldSpacecraftState<T> state, FieldTLE<T> templateTLE, TimeScale utc, Frame teme, double epsilon, int maxIterations) Convert Spacecraft State into TLE.
String	toString() Get a string representation of this TLE set.
TLE	toTLE() Convert FieldTLE into TLE.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

DEFAULT

public static final int DEFAULT

Identifier for default type of ephemeris (SGP4/SDP4).

See Also:

Constant Field Values

SGP

public static final int SGP

Identifier for SGP type of ephemeris.

See Also:

Constant Field Values

SGP4

public static final int SGP4

Identifier for SGP4 type of ephemeris.

See Also:

Constant Field Values

SDP4

public static final int SDP4

Identifier for SDP4 type of ephemeris.

See Also:

Constant Field Values

SGP8

public static final int SGP8

Identifier for SGP8 type of ephemeris.

See Also:

Constant Field Values

SDP8

public static final int SDP8

Identifier for SDP8 type of ephemeris.

See Also:

Constant Field Values

B_STAR

public static final String B_STAR

Parameter name for B* coefficient.

See Also:

Constant Field Values

Constructor Detail

FieldTLE

@DefaultDataContext
public FieldTLE(Field<T> field,
                                    String line1,
                                    String line2)

Simple constructor from unparsed two lines. This constructor uses the default data context.

The static method isFormatOK(String, String) should be called before trying to build this object.

Parameters:

field - field utilized by default

line1 - the first element (69 char String)

line2 - the second element (69 char String)

See Also:

FieldTLE(Field, String, String, TimeScale)

FieldTLE

public FieldTLE(Field<T> field,
                String line1,
                String line2,
                TimeScale utc)

Simple constructor from unparsed two lines using the given time scale as UTC.

This method uses the default data context.

The static method isFormatOK(String, String) should be called before trying to build this object.

Parameters:

field - field utilized by default

line1 - the first element (69 char String)

line2 - the second element (69 char String)

utc - the UTC time scale.

FieldTLE

@DefaultDataContext
public FieldTLE(int satelliteNumber,
                                    char classification,
                                    int launchYear,
                                    int launchNumber,
                                    String launchPiece,
                                    int ephemerisType,
                                    int elementNumber,
                                    FieldAbsoluteDate<T> epoch,
                                    T meanMotion,
                                    T meanMotionFirstDerivative,
                                    T meanMotionSecondDerivative,
                                    T e,
                                    T i,
                                    T pa,
                                    T raan,
                                    T meanAnomaly,
                                    int revolutionNumberAtEpoch,
                                    double bStar)

Simple constructor from already parsed elements. This constructor uses the default data context.

The mean anomaly, the right ascension of ascending node Ω and the argument of perigee ω are normalized into the [0, 2π] interval as they can be negative. After that, a range check is performed on some of the orbital elements:

     meanMotion >= 0
     0 <= i <= π
     0 <= Ω <= 2π
     0 <= e <= 1
     0 <= ω <= 2π
     0 <= meanAnomaly <= 2π
 

Parameters:

satelliteNumber - satellite number

classification - classification (U for unclassified)

launchYear - launch year (all digits)

launchNumber - launch number

launchPiece - launch piece (3 char String)

ephemerisType - type of ephemeris

elementNumber - element number

epoch - elements epoch

meanMotion - mean motion (rad/s)

meanMotionFirstDerivative - mean motion first derivative (rad/s²)

meanMotionSecondDerivative - mean motion second derivative (rad/s³)

e - eccentricity

i - inclination (rad)

pa - argument of perigee (rad)

raan - right ascension of ascending node (rad)

meanAnomaly - mean anomaly (rad)

revolutionNumberAtEpoch - revolution number at epoch

bStar - ballistic coefficient

See Also:

FieldTLE(int, char, int, int, String, int, int, FieldAbsoluteDate, CalculusFieldElement, CalculusFieldElement, CalculusFieldElement, CalculusFieldElement, CalculusFieldElement, CalculusFieldElement, CalculusFieldElement, CalculusFieldElement, int, double, TimeScale)

FieldTLE

public FieldTLE(int satelliteNumber,
                char classification,
                int launchYear,
                int launchNumber,
                String launchPiece,
                int ephemerisType,
                int elementNumber,
                FieldAbsoluteDate<T> epoch,
                T meanMotion,
                T meanMotionFirstDerivative,
                T meanMotionSecondDerivative,
                T e,
                T i,
                T pa,
                T raan,
                T meanAnomaly,
                int revolutionNumberAtEpoch,
                double bStar,
                TimeScale utc)

Simple constructor from already parsed elements using the given time scale as UTC.

The mean anomaly, the right ascension of ascending node Ω and the argument of perigee ω are normalized into the [0, 2π] interval as they can be negative. After that, a range check is performed on some of the orbital elements:

     meanMotion >= 0
     0 <= i <= π
     0 <= Ω <= 2π
     0 <= e <= 1
     0 <= ω <= 2π
     0 <= meanAnomaly <= 2π
 

Parameters:

satelliteNumber - satellite number

classification - classification (U for unclassified)

launchYear - launch year (all digits)

launchNumber - launch number

launchPiece - launch piece (3 char String)

ephemerisType - type of ephemeris

elementNumber - element number

epoch - elements epoch

meanMotion - mean motion (rad/s)

meanMotionFirstDerivative - mean motion first derivative (rad/s²)

meanMotionSecondDerivative - mean motion second derivative (rad/s³)

e - eccentricity

i - inclination (rad)

pa - argument of perigee (rad)

raan - right ascension of ascending node (rad)

meanAnomaly - mean anomaly (rad)

revolutionNumberAtEpoch - revolution number at epoch

bStar - ballistic coefficient

utc - the UTC time scale.

Method Detail

getLine1

public String getLine1()

Get the first line.

Returns:

first line

getLine2

public String getLine2()

Get the second line.

Returns:

second line

getParametersDrivers

public List<ParameterDriver> getParametersDrivers()

Get the drivers for TLE propagation SGP4 and SDP4.

Returns:

drivers for SGP4 and SDP4 model parameters

getParameters

public T[] getParameters(Field<T> field)

Get model parameters.

Parameters:

field - field to which the elements belong

Returns:

model parameters

getSatelliteNumber

public int getSatelliteNumber()

Get the satellite id.

Returns:

the satellite number

getClassification

public char getClassification()

Get the classification.

Returns:

classification

getLaunchYear

public int getLaunchYear()

Get the launch year.

Returns:

the launch year

getLaunchNumber

public int getLaunchNumber()

Get the launch number.

Returns:

the launch number

getLaunchPiece

public String getLaunchPiece()

Get the launch piece.

Returns:

the launch piece

getEphemerisType

public int getEphemerisType()

Get the type of ephemeris.

Returns:

the ephemeris type (one of DEFAULT, SGP, SGP4, SGP8, SDP4, SDP8)

getElementNumber

public int getElementNumber()

Get the element number.

Returns:

the element number

getDate

public FieldAbsoluteDate<T> getDate()

Get the TLE current date.

Specified by:

getDate in interface FieldTimeStamped<T extends CalculusFieldElement<T>>

Returns:

the epoch

getMeanMotion

public T getMeanMotion()

Get the mean motion.

Returns:

the mean motion (rad/s)

getMeanMotionFirstDerivative

public T getMeanMotionFirstDerivative()

Get the mean motion first derivative.

Returns:

the mean motion first derivative (rad/s²)

getMeanMotionSecondDerivative

public T getMeanMotionSecondDerivative()

Get the mean motion second derivative.

Returns:

the mean motion second derivative (rad/s³)

getE

public T getE()

Get the eccentricity.

Returns:

the eccentricity

getI

public T getI()

Get the inclination.

Returns:

the inclination (rad)

getPerigeeArgument

public T getPerigeeArgument()

Get the argument of perigee.

Returns:

omega (rad)

getRaan

public T getRaan()

Get Right Ascension of the Ascending node.

Returns:

the raan (rad)

getMeanAnomaly

public T getMeanAnomaly()

Get the mean anomaly.

Returns:

the mean anomaly (rad)

getRevolutionNumberAtEpoch

public int getRevolutionNumberAtEpoch()

Get the revolution number.

Returns:

the revolutionNumberAtEpoch

getBStar

public double getBStar()

Get the ballistic coefficient.

Returns:

bStar

toString

public String toString()

Get a string representation of this TLE set.

The representation is simply the two lines separated by the platform line separator.

Overrides:

toString in class Object

Returns:

string representation of this TLE set

stateToTLE

@DefaultDataContext
public static <T extends CalculusFieldElement<T>> FieldTLE<T> stateToTLE(FieldSpacecraftState<T> state,
                                                                                             FieldTLE<T> templateTLE)

Convert Spacecraft State into TLE. This converter uses Newton method to reverse SGP4 and SDP4 propagation algorithm and generates a usable TLE version of a state. New TLE epoch is state epoch.

This method uses the default data context, as well as EPSILON_DEFAULT and MAX_ITERATIONS_DEFAULT for method convergence.

Type Parameters:

T - type of the element

Parameters:

state - Spacecraft State to convert into TLE

templateTLE - first guess used to get identification and estimate new TLE

Returns:

TLE matching with Spacecraft State and template identification

Since:

11.0

See Also:

stateToTLE(FieldSpacecraftState, FieldTLE, TimeScale, Frame), stateToTLE(FieldSpacecraftState, FieldTLE, TimeScale, Frame, double, int)

stateToTLE

public static <T extends CalculusFieldElement<T>> FieldTLE<T> stateToTLE(FieldSpacecraftState<T> state,
                                                                         FieldTLE<T> templateTLE,
                                                                         TimeScale utc,
                                                                         Frame teme)

Convert Spacecraft State into TLE. This converter uses Newton method to reverse SGP4 and SDP4 propagation algorithm and generates a usable TLE version of a state. New TLE epoch is state epoch.

This method uses EPSILON_DEFAULT and MAX_ITERATIONS_DEFAULT for method convergence.

Type Parameters:

T - type of the element

Parameters:

state - Spacecraft State to convert into TLE

templateTLE - first guess used to get identification and estimate new TLE

utc - the UTC time scale

teme - the TEME frame to use for propagation

Returns:

TLE matching with Spacecraft State and template identification

Since:

11.0

See Also:

stateToTLE(FieldSpacecraftState, FieldTLE, TimeScale, Frame, double, int)

stateToTLE

public static <T extends CalculusFieldElement<T>> FieldTLE<T> stateToTLE(FieldSpacecraftState<T> state,
                                                                         FieldTLE<T> templateTLE,
                                                                         TimeScale utc,
                                                                         Frame teme,
                                                                         double epsilon,
                                                                         int maxIterations)

Convert Spacecraft State into TLE. This converter uses Newton method to reverse SGP4 and SDP4 propagation algorithm and generates a usable TLE version of a state. New TLE epoch is state epoch.

Type Parameters:

T - type of the element

Parameters:

state - Spacecraft State to convert into TLE

templateTLE - first guess used to get identification and estimate new TLE

utc - the UTC time scale

teme - the TEME frame to use for propagation

epsilon - used to compute threshold for convergence check

maxIterations - maximum number of iterations for convergence

Returns:

TLE matching with Spacecraft State and template identification

Since:

11.0

isFormatOK

public static boolean isFormatOK(String line1,
                                 String line2)

Check the lines format validity.

Parameters:

line1 - the first element

line2 - the second element

Returns:

true if format is recognized (non null lines, 69 characters length, line content), false if not

toTLE

public TLE toTLE()

Convert FieldTLE into TLE.

Returns:

TLE

equals

public boolean equals(Object o)

Check if this tle equals the provided tle.

Due to the difference in precision between object and string representations of TLE, it is possible for this method to return false even if string representations returned by toString() are equal.

Overrides:

equals in class Object

Parameters:

o - other tle

Returns:

true if this tle equals the provided tle

hashCode

public int hashCode()

Get a hashcode for this tle.

Overrides:

hashCode in class Object

Returns:

hashcode