Data Provider Groups | Data Provider Elements

Spherical Elements

The position and velocity of the object with respect to the object's central body, as observed from the requested coordinate system, expressed in spherical elements as a function of time.

Available for these objects: LaunchVehicle, Missile, Satellite

Type: Time-varying data.

Availability: Reports | Graphs | Dynamic Displays | Strip Charts

Data Provider Groups

Data can be requested in a variety of coordinate systems, where the origin of the coordinate system is the object's central body. The available coordinate systems depend on the object's central body. Nominally, the systems Fixed, Inertial, J2000, TrueOfDate, and MeanOfDate are supported, although some central bodies (notably the Earth and Sun) have more.

The following lists the systems available for Earth.

Name	Description
TrueOfDateRotating	A variation of the Fixed system where pole wander is ignored. The equator is the same as the TrueOfDate equator and the frame spins about the TrueOfDate z-axis.
Fixed	A coordinate system attached to the central body and rotating with it. The z-axis is nominally along the rotation axis.
ICRF	International Celestial Reference Frame. The ICRF axes are defined as the inertial (i.e., kinematically non-rotating) axes associated with a general relativity frame centered at the solar system barycenter (often called the BCRF).
MeanOfDate	The mean equator mean equinox coordinate system evaluated at the requested time.
MeanOfEpoch	The mean equator mean equinox coordinate system evaluated at the epoch of the object.
TrueOfDate	The true equator true equinox coordinate system evaluated at the requested time.
TrueOfEpoch	The true equator true equinox coordinate system evaluated at the epoch of the object.
B1950	The mean equator mean equinox coordinate system evaluated at the beginning of the Besselian year 1950 (31 December 1949 22:09:46.866 = JD 2433282.4234591).
TEMEOfEpoch	The true equator mean equinox coordinate system evaluated at the epoch of the object.
TEMEOfDate	The true equator mean equinox coordinate system evaluated at the requested time.
AlignmentAtEpoch	The non-rotating coordinate system coincident with the Fixed system evaluated at the object's coordinate reference epoch.
J2000	The mean equator mean equinox coordinate system evaluated at the J2000.0 epoch (2000 January 1.5 TDB = JD 2451545.0 TDB).

Data Provider Elements

Name	Dimension	Type	Description
Time	Date	Real Number or Text	Time.
Right Ascen	Longitude	Real Number or Text	The signed angle measured from the X axis to the projection of the position vector into the XY plane. The angle increases in the direction found by the right hand rule about the Z axis.
Declination	Angle	Real Number or Text	The signed angle measured from the XY plane to the position vector, where positive angles are used for locations above the XY plane, and negative for those below.
Radius	Distance	Real Number	The magnitude of the position vector (i.e. the radius vector).
Horiz Flt Path Ang	Angle	Real Number or Text	The angle between the position vector and the plane whose normal is the velocity vector.
Inertial Flt Path Azi	Longitude	Real Number or Text	The angle, measured in the plane perpendicular to the position vector, between the local north direction and the projection of the velocity vector onto that plane, measured as positive moving toward local east.
Inertial Vel	Rate	Real Number	The magnitude of the velocity vector, as observed in the coordinate system.