Data Providers: 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.

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.