Satellite: Astrogator Values: Relative Motion

Calc Objects for relative ephemeris. The relative ephemeris is computed with respect to two rotating frames, the RIC (Radial, In-Track, Cross-Track) frame and the NTC (Normal, Tangential, and Cross-Track) frames, that are defined using the primary's ephemeris. Cross-track refers to the direction perpendicular to the position and inertial velocity; in-track refers to the direction perpendicular to both the radial and cross-track (positive in the direction of motion); tangential refers to the direction along the velocity vector; and normal refers to the direction perpendicular to the velocity and cross-track directions (positive outward along radial). Each Calc Object allows a choice of a central body. The default is Earth. See Also Formation

Name Dimension Type Description
Time DateFormat Real Number Time.
CrossTrack DistanceUnit Real Number The cross-track component of the relative position vector.
CrossTrackRate Rate Real Number The cross-track component of the relative velocity vector as observed in the RIC rotating frame.
InTrack DistanceUnit Real Number The in-track component of the relative position vector.
InTrackRate Rate Real Number The in-track component of the relative velocity vector as observed in the RIC rotating frame.
Normal DistanceUnit Real Number The normal component of the relative position vector.
NormalRate Rate Real Number The normal component of the relative velocity vector as observed in the NTC rotating frame.
RICAzimuth AngleUnit Real Number The angle measured in the plane formed by the in-track and cross-track directions, positive from the In-Track direction toward the Cross-Track direction
RICAzimuthRate AngleRateUnit Real Number The rate of change of the RIC azimuth
RICElevation AngleUnit Real Number The angle measured perpendicular to the plane formed by the in-track and cross-track directions, positive toward the Radial direction
RICElevationRate AngleRateUnit Real Number The rate of change of the RIC elevation
Radial DistanceUnit Real Number The radial component of the relative position vector.
RadialRate Rate Real Number The radial component of the relative velocity vector as observed in the RIC rotating frame.
Range DistanceUnit Real Number The range (i.e., distance between the primary and secondary object) at the given time.
RangeRate Rate Real Number The rate of change of the magnitude of the relative position vector.
Tangential DistanceUnit Real Number The tangential component of the relative position vector.
TangentialRate Rate Real Number The tangential component of the relative velocity vector as observed in the NTC rotating frame.
TimeDifference TimeUnit Real Number Alternative measure for in-track position difference, computed as as duration. The duration is computed by dividing the in-track component of the relative position vector by the inertial velocity of the primary object.

STK Programming Interface 11.0.1