Satellite: Ephemeris Diff in Curvilinear Coordinates

The relative ephemeris of the assigned object with respect to the primary object, expressed in curvilinear coordinates, as a function of time. It produces three coordinates and their rates (Crossrange, Downrange, and Crosstrack) that are defined relative to the osculating orbit of the reference satellite.

Type: Time-varying data

Availability: Reports | Graphs | Dynamic Displays | Strip Charts

NameDimensionTypeDescription
TimeDateFormatReal NumberTime.
CrossrangeDistanceUnitReal NumberCross range is in the orbit plane along the outward normal to the osculating orbital ellipse.
DownrangeDistanceUnitReal NumberDown range is along the curved orbit in the direction of flight.
CrosstrackDistanceUnitReal NumberCross track is orthogonal to the osculating orbital plane completing the right-handed triad.
Crossrange RateRateReal NumberRate of change of the cross range coordinate.
Downrange RateRateReal NumberRate of change of the down range coordinate.
Crosstrack RateRateReal NumberRate of change of the cross track coordinate.
Position Combined Cov SigmaUnitlessReal NumberPosition difference measured in terms of the combined position covariance of primary and target satellites. Reports N where the current relative position vector lies on an N sigma ellipsoid, where the ellipsoid is obtained from the sum of the covariances matrices of the two objects. This can only be computed if position covariance is available.
Position Cov SigmaUnitlessReal NumberPosition difference measured in terms of the position covariance. Reports N where the current relative position vector lies on a N sigma ellipsoid, where the ellipsoid if obtained from the position covariance of the primary satellite. This can only be computed if position covariance is available.