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CcsdsOrbitEphemerisMessageSegmentCovarianceAxes Property

Gets or sets a collection containing the axes of the covariance data.

This collection is not provided automatically by ReadFrom(String) because the axes provided with OEM covariance data are optional, and they are not necessarily supported as Axes objects.

If this is not provided by the user, an attempt will be made to build a collection of axes from the axes of given reference frame, the covariance axes names collection, and other data provided by the OEM file. If this attempt fails, will be returned. The user would then have to build this collection manually.

Note that this data is not required by CreatePoint.

Namespace:  AGI.Foundation.Ccsds
Assembly:  AGI.Foundation.Models (in AGI.Foundation.Models.dll) Version: 24.2.419.0 (24.2.419.0)
Syntax
public DateMotionCollection<Axes> CovarianceAxes { get; set; }

Property Value

Type: DateMotionCollectionAxes
Remarks

All the reference frames supported in the remarks of ReferenceFrame are also supported. Additionally, several of the Orbit-Relative Reference Frames available at the SANA website are supported. Because these frames are orbit relative, the inference algorithm attempts to use CreatePoint to generate the orbit that is used to define the coordinates. If CreatePoint fails by throwing an exception, then will be returned. Additionally, a CentralBody must be able to be inferred from Center in order for the inference to work.

All the orbit relative systems other than SEZ/SEZ_ROTATING use the non-null ReferenceFrame if the ReferenceFrameType is Inertial. Otherwise, they use the InertialFrame of the CentralBody.

  • SEZ and SEZ_ROTATING use the South/East/Zenith topocentric horizon system. This system is right-handed, Cartesian system rotating with the observing site. The local horizon forms the fundamental plane, with the S axis pointing due south from the site (even in the Southern Hemisphere). The E axis points east from the site. The Z axis (zenith) points radially outward from the site, along the site's geodetic local vertical. SEZ and SEZ_ROTATING use the non-null ReferenceFrame if the ReferenceFrameType is Fixed. Otherwise, they use the FixedFrame of the CentralBody.
  • LVLH and LVLH_ROTATING stand for "Local Vertical Local Horizontal". The Z-axis of the rotating LVLH frame is a unit vector collinear and opposite sign of the gravicentric satellite position (planet center, spacecraft gravity center), the Y-axis is a unit vector collinear but with the opposite sign of the orbital kinetic momentum (normal to orbit plane), and the X-axis completes the orthonormal triad.
  • VNC, VNC_ROTATING, and VNB define a local orbital coordinate Velocity, Normal, Co-normal (Bi-normal for VNB) rotating frame that has the x-axis along the Velocity (or tangential) vector, y-axis Normal to the orbit along the orbital angular momentum vector, and z-axis is the "Co-normal" direction completing the right-handed system (i.e. for a circular orbit "C" points in the radius vector direction whereas for an eccentric orbit, "C" points as close to radial as possible while still being normal to the V-N plane).
  • RSW, RSW_ROTATING, RTN, RIC, and QSW define a Radial, Along track, Cross track, local orbital coordinate rotating frame, where the R axis always points out from the satellite along the central body's radius vector to the satellite as it moves through the orbit. The S axis is in the direction of (but not necessarily parallel to) the velocity vector and is perpendicular to the radius vector. The W axis is aligned with the orbit angular momentum vector.
  • NTW, NTW_ROTATING, and TVN define a local orbital coordinate rotating frame that has the y-axis along the Tangential (or inertial velocity) vector, z-axis ("W") along the orbital angular momentum vector, and N (the x-axis) completing the right-handed system (i.e., for a circular orbit "N" generally points in the radial direction and for an eccentric orbit, "N" points as close to radial as possible while still being normal to the T-W plane.
  • TNW and TNW_ROTATING define a local orbital coordinate Tangential, Normal, Cross-track rotating frame that has the x-axis along the Tangential (or velocity) vector, z-axis ("W") along the orbital angular momentum vector, and N completing the right-handed system (i.e. for a circular orbit "N" generally points in the Nadir direction and for an eccentric orbit, "N" points as close to Nadir as possible while still being normal to the T-W plane).
See Also