TwoLineElementSet Class

A NORAD two-line element set (TLE). Note that the precision of most TLEs is limited by the string representations in the TLE. The resulting ephemeris has a precision on the order of kilometers. When creating a TLE based on orbital elements, it is important to note that information will be lost when converting precise elements into a string representation.

Inheritance Hierarchy

SystemObject
AGI.Foundation.PropagatorsSgp4Elements
AGI.Foundation.PropagatorsTwoLineElementSet

Namespace: AGI.Foundation.Propagators
Assembly: AGI.Foundation.Models (in AGI.Foundation.Models.dll) Version: 24.2.419.0 (24.2.419.0)

Syntax

C++

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public class TwoLineElementSet : Sgp4Elements

Public Class TwoLineElementSet
	Inherits Sgp4Elements

public ref class TwoLineElementSet : public Sgp4Elements

type TwoLineElementSet =  
    class
        inherit Sgp4Elements
    end

The TwoLineElementSet type exposes the following members.

Constructors

	Name	Description
	TwoLineElementSet	Initializes a new Two Line Element Set with default parameters.
	TwoLineElementSet(String)	Initializes a new Two Line Element Set from a string representation of the TLE. An invalid checksum value will be silently ignored.
	TwoLineElementSet(TwoLineElementSet)	Initializes a new instance as a copy of an existing instance.
	TwoLineElementSet(String, Boolean)	Initializes a new Two Line Element Set from a string representation of the TLE and optionally verifies the checksums.
	TwoLineElementSet(String, Boolean, Char)	Initializes a new Two Line Element Set from a string representation of the TLE and optionally verifies the checksums.
	TwoLineElementSet(Sgp4Elements, String, String, String, String, Double, Double, Int32, Int32)	Initializes a new Two Line Element Set (TLE) from a set of Sgp4Elements and additional meta-data contained in the TLE format.

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Properties

	Name	Description
	ArgumentOfPerigee	Gets or sets the argument of perigee, in degrees. (Inherited from Sgp4Elements.)
	BStar	Gets or sets the BSTAR drag term, in units of 1 / EarthRadii. This term represents a modification of the ballistic coefficient (Coefficient of drag times area over mass). The value is modified by one half atmospheric density and expressed in units of inverse Earth radii. Source: https://celestrak.com/ (Inherited from Sgp4Elements.)
	ChecksumLine1	Gets or sets the checksum for line 1.
	ChecksumLine2	Gets or sets the checksum for line 2.
	Classification	Gets or sets the classification.
	Eccentricity	Gets or sets the eccentricity (Inherited from Sgp4Elements.)
	ElementNumber	Gets or sets the element number
	EphemerisType	Gets or sets the ephemeris type. Ephemeris Type 0 is the correct type for Sgp4Propagator. Ephemeris type 4 is not supported by Sgp4Propagator, and it will throw an argument exception if a TwoLineElementSet has ephemeris type 4.
	Epoch	Gets or sets the epoch at which these initial conditions are defined. Note: The epoch will only be represented to the precision of the TwoLineElementSet format from the RawEpoch. For greater precision, use Sgp4Elements directly. (Overrides Sgp4ElementsEpoch.)
	Inclination	Gets or sets the inclination, in degrees (Inherited from Sgp4Elements.)
	InternationalDesignator	Gets or sets the international designator
	MeanAnomaly	Gets or sets the mean anomaly, in degrees. (Inherited from Sgp4Elements.)
	MeanMotion	Gets or sets the mean motion, in revolutions per day. (Inherited from Sgp4Elements.)
	MeanMotionDot	Gets or sets the first derivative of mean motion divided by two, in revolutions per day squared.
	MeanMotionDotDot	Gets or sets the second derivative of mean motion divided by six, in revolutions per day cubed.
	Name	Gets or sets the spacecraft name
	RawEpoch	Gets or sets the epoch at which these initial conditions are defined, represented in the standard form: YYDDD.DDDD. Note: this will be represented to only the precision of the TwoLineElementSet format. For greater precision, use Sgp4Elements directly. (Overrides Sgp4ElementsRawEpoch.)
	RevolutionNumber	Gets or sets the revolution number at epoch.
	RightAscensionOfAscendingNode	Gets or sets the right ascension of the ascending node, in degrees (Inherited from Sgp4Elements.)
	SatelliteNumber	Gets or sets the satellite number.
	SwitchingMethod	Gets or sets the method to use when switching between this element set and the following element set. By default, this is Sgp4ElementsSwitchByEpoch. (Inherited from Sgp4Elements.)

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Methods

	Name	Description
	Clone	Clones this object using the specified context. (Overrides Sgp4ElementsClone(CopyContext).)
	DownloadTles(String, JulianDate, JulianDate)	Downloads TLE data for a given satellite from an AGI server. Multiple TLEs are returned, spanning the interval provided. This method connects via HTTPS to ftp.agi.com.
	DownloadTles(String, JulianDate, JulianDate, IWebProxy)	Downloads TLE data for a given satellite from an AGI server. Multiple TLEs are returned, spanning the interval provided. This method connects via HTTPS to ftp.agi.com.
	Equals	Determines whether the specified object is equal to the current object. (Inherited from Object.)
	Finalize	Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
	GetHashCode	Serves as the default hash function. (Inherited from Object.)
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	ToString	Returns a string that represents the current object. (Inherited from Object.)
	ToTleString	Returns a TLE string representing this TwoLineElementSet in the standard NORAD format, described by CelesTrak. The format consists of two or three lines with a new line after each. If the Name is not and not empty, the output contains three lines where the first is the result of ToTleStringLine0, the second is the result of ToTleStringLine1, and the third is the result of ToTleStringLine2. If the name is or empty, line zero is omitted. In either case, the lines are separated by your platform's new line string, usually "\n" or "\r\n".
	ToTleStringLine0	Returns line 0 of the TLE represented in standard NORAD format, described by CelesTrak. Line 0 contains the Name padded to 24 characters. The returned line does not contain any new line or line break characters.
	ToTleStringLine1	Returns line 1 of the TLE represented in standard NORAD format, described by CelesTrak. Line 1 contains the classification, international designator, epoch, etc. The returned line does not contain any new line or line break characters.
	ToTleStringLine2	Returns line 2 of the TLE represented in standard NORAD format, described by CelesTrak. Line 2 contains the inclination, right ascension of the ascending node, eccentricity, etc. The returned line does not contain any new line or line break characters.
	TryConvertAlpha5SatelliteCatalogNumbersToIntegers	Tries to convert an Alpha-5 satellite catalog number into its corresponding integer representation.
	TryConvertIntegerSatelliteCatalogNumbersToAlpha5	Tries to convert an integer satellite catalog number into its corresponding Alpha-5 representation.
	VerifyChecksum	Verifies the checksum of the specified TLE line.

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Remarks

Warning: If the EphemerisType is 4, the TLE field for BStar is actually the ballistic coefficient (Coefficient of drag times area over mass), the TLE field for MeanMotionDotDot is actually the AGOM (Area times coefficient of solar radiation pressure over mass), and Sgp4Propagator will throw an exception if the TLE is input.

Examples

The following example shows how to create a TLE from a string and then use it to create an Sgp4Propagator:

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string tleString =
    "1 20724U 90068A   02173.73395695 -.00000086  00000-0  00000-0 0  1771\n" +
    "2 20724  56.1487  21.0845 0183651 226.6216 131.8780  2.00562381 85500\n";
TwoLineElementSet tle = new TwoLineElementSet(tleString);
Sgp4Propagator propagator = new Sgp4Propagator(tle);

Reference

AGI.Foundation.Propagators Namespace