Data Provider Groups | Data Provider Elements

To Position Velocity

Reports the apparent position and velocity information of the target object as observed from the base object, expressed with respect to the base object's central body.

Planets report position and velocity with respect to the Sun.



Available for these objects: Access

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.
NameDescription
FixedA coordinate system attached to the central body and rotating with it. The z-axis is nominally along the rotation axis.
ICRFInternational 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).
MeanOfDateThe mean equator mean equinox coordinate system evaluated at the requested time.
MeanOfEpochThe mean equator mean equinox coordinate system evaluated at the epoch of the object.
TrueOfDateThe true equator true equinox coordinate system evaluated at the requested time.
TrueOfEpochThe true equator true equinox coordinate system evaluated at the epoch of the object.
B1950The 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).
TEMEOfEpochThe true equator mean equinox coordinate system evaluated at the epoch of the object.
TEMEOfDateThe true equator mean equinox coordinate system evaluated at the requested time.
AlignmentAtEpochThe non-rotating coordinate system coincident with the Fixed system evaluated at the object's coordinate reference epoch.
J2000The mean equator mean equinox coordinate system evaluated at the J2000.0 epoch (2000 January 1.5 TDB = JD 2451545.0 TDB).
BodyThe body fixed axes of the base object.

Data Provider Elements

NameDimensionTypeDescription
TimeDateFormatReal NumberTime.
xDistanceUnitReal NumberThe X component of the apparent position vector.
yDistanceUnitReal NumberThe Y component of the apparent position vector.
zDistanceUnitReal NumberThe Z component of the apparent position vector.
RangeDistanceUnitReal NumberThe magnitude of the apparent position vector.
x/RangeUnitlessReal NumberThe direction cosine for the X-axis.
y/RangeUnitlessReal NumberThe direction cosine for the Y-axis.
z/RangeUnitlessReal NumberThe direction cosine for the Z-axis.
xVelRateReal NumberThe X-component of apparent velocity.
yVelRateReal NumberThe Y-component of apparent velocity.
zVelRateReal NumberThe Z-component of apparent velocity.
RelSpeedRateReal NumberThe magnitude of the apparent velocity vector.
Right AscenLongitudeUnitReal NumberThe signed angle measured from the X axis to the projection of the apparent position vector into the XY plane. The angle increases in the direction found by the right hand rule about the Z axis.
DeclinationLatitudeUnitReal NumberThe angle between the apparent position vector and the XY-plane. The angle is positive when the Z component is positive.
LightTimeDelayTimeUnitReal NumberThe light time delay used in computing the base and target object's location.