Data Providers: AdvCAT: Event Ephemeris

AdvCAT: Event Ephemeris

Reports ephemeris and other related information as a function of time for each close approach event.

Type: Time-varying data. Intended to be used only with elements from this same data provider.

Availability: Reports

Name	Dimension	Type	Description
Approach Angle	AngleUnit	Real Number	The angle between the inertial velocity of the primary object and the inertial velocity of the secondary object at the given time
Ellipsoid Norm wrt Primary	Unitless	Real Number or Text	A measure of the "distance" between the primary and secondary object, using the primary object's ellipsoid size as a norm, at the given time. If the primary ellipsoid size were to be scaled uniformly by this value, then the ellipsoid would just touch the secondary. The value is set to "Undefined" if an error occurs computing the norm.
Ellipsoid Norm wrt Secondary	Unitless	Real Number or Text	A measure of the "distance" between the primary and secondary object, using the secondary object's ellipsoid size as a norm, at the given time. If the secondary ellipsoid size were to be scaled uniformly by this value, then the ellipsoid would just touch the primary. The value is set to "Undefined" if an error occurs computing the norm.
Primary Alt	DistanceUnit	Real Number	The primary object's detic altitude at the given time.
Primary Concurrent Events	Unitless	Integer	The number of secondaries experiencing a close approach event with the primary at this time.
Primary Ellipsoid - CrossTrack	DistanceUnit	Real Number	For a Covariance class threat volume, this is the crosstrack position-estimation-error standard deviation for the primary vehicle. For other threat ellipsoid types expressed in the TCN principal axes frame, this is the length of the crosstrack-aligned semi-axis.
Primary Ellipsoid - Max	DistanceUnit	Real Number	The length of the longest symmetry axis of the primary object's ellipsoid at the given time.
Secondary Alt	DistanceUnit	Real Number	The secondary object's detic altitude at the given time.
Primary Ellipsoid - Middle	DistanceUnit	Real Number	The length of the intermediate symmetry axis of the primary object's ellipsoid at the given time.
Primary Ellipsoid - Min	DistanceUnit	Real Number	The length of the shortest symmetry axis of the primary object's ellipsoid at the given time.
Range wrt Primary - CrossTrack	DistanceUnit	Real Number	The component of the relative position vector (i.e., secondary position vector minus primary position vector) in the primary object's cross-track direction at the given time. The cross-track direction lies along the object's orbit normal.
Primary Ellipsoid - Normal	DistanceUnit	Real Number	For a Covariance class threat volume, this is the normal position-estimation-error standard deviation for the primary vehicle. For other threat ellipsoid types expressed in the TCN principal axes frame, this is the length of the normal-aligned semi-axis.
Secondary Lat	LatitudeUnit	Real Number	The secondary object's detic latitude at the given time.
Primary Ellipsoid - Tangential	DistanceUnit	Real Number	For a Covariance class threat volume, this is the tangential position-estimation-error standard deviation for the primary vehicle. For other threat ellipsoid types expressed in the TCN principal axes frame, this is the length of the tangential-aligned semi-axis.
Secondary Lon	LongitudeUnit	Real Number	The secondary object's detic longitude at the given time.
Secondary Ellipsoid - CrossTrack	DistanceUnit	Real Number	For a Covariance class threat volume, this is the crosstrack position-estimation-error standard deviation for the secondary vehicle. For other threat ellipsoid types expressed in the TCNl principal axes frame, this is the length of the crosstrack-aligned semi-axis.
Range wrt Primary - Tangential	DistanceUnit	Real Number	The component of the relative position vector (i.e., secondary position vector minus primary position vector) in the primary object's tangential direction at the given time. The tangential direction lies along the object's inertial velocity.
Range wrt Primary - Normal	DistanceUnit	Real Number	The component of the relative position vector (i.e., secondary position vector minus primary position vector) in the primary object's normal direction at the given time. The normal direction completes a triad involving the tangential and cross-track directions and is akin to the radial direction.
Secondary Ellipsoid - Max	DistanceUnit	Real Number	The length of the longest symmetry axis of the secondary object's ellipsoid at the given time.
Secondary x	DistanceUnit	Real Number	The X component of the inertial position vector of the secondary object at the given time.
Secondary Ellipsoid - Tangential	DistanceUnit	Real Number	For a Covariance class threat volume, this is the tangential position-estimation-error standard deviation for the secondary vehicle. For other threat ellipsoid types expressed in the TCN principal axes frame, this is the length of the tangential-aligned semi-axis.
Secondary y	DistanceUnit	Real Number	The Y component of the inertial position vector of the secondary object at the given time.
Secondary: Time Since Epoch	TimeUnit	Real Number	The difference between the given time time and the secondary object's epoch.
Primary Lat	LatitudeUnit	Real Number	The primary object's detic latitude at the given time.
Secondary Ellipsoid - Normal	DistanceUnit	Real Number	For a Covariance class threat volume, this is the normal position-estimation-error standard deviation for the secondary vehicle. For other threat ellipsoid types expressed in the TCN principal axes frame, this is the length of the normal-aligned semi-axis.
Secondary z	DistanceUnit	Real Number	The Z component of the inertial position vector of the secondary object at the given time.
Secondary vx	Rate	Real Number	The X component of the inertial velocity vector of the secondary object at the given time.
Secondary Ellipsoid - Middle	DistanceUnit	Real Number	The length of the intermediate symmetry axis of the secondary object's ellipsoid at the given time.
Secondary vy	Rate	Real Number	The Y component of the inertial velocity vector of the secondary object at the given time.
Range wrt Primary - Radial	DistanceUnit	Real Number	The component of the relative position vector (i.e., secondary position vector minus primary position vector) in the primary object's radial direction at the given time.
Secondary vz	Rate	Real Number	The Z component of the inertial velocity vector of the secondary object at the given time.
Secondary Ellipsoid - Min	DistanceUnit	Real Number	The length of the shortest symmetry axis of the secondary object's ellipsoid at the given time.
Range wrt Primary - InTrack	DistanceUnit	Real Number	The component of the relative position vector (i.e., secondary position vector minus primary position vector) in the primary object's in-track direction at the given time. The in-track direction completes a triad involving the radial and cross-track directions.
Primary Lon	LongitudeUnit	Real Number	The primary object's detic longitude at the given time.
Primary NumberID	Unitless	Text	The number identifier of the primary object involved in the close approach event. If the object has no number identifier, then the value will be "Not Avail".
Secondary Pitch	AngleUnit	Real Number	The pitch angle for the secondary object's ellipsoid at the given time. The pitch angle locates the major axis of the ellipsoid from the plane whose normal is the cross-track direction.
Primary Pitch	AngleUnit	Real Number	The pitch angle for the primary object's ellipsoid at the given time. The pitch angle locates the major axis of the ellipsoid from the plane whose normal is the cross-track direction.
Secondary Roll	AngleUnit	Real Number	The roll angle for the secondary object's ellipsoid at the given time. The roll angle locates the minor axis of the ellipsoid as a rotation about the major axis, with zero being aligned with the cross-track direction.
Secondary Yaw	AngleUnit	Real Number	The yaw angle for the secondary object's ellipsoid at the given time. The yaw angle locates from the tangential direction the projection of the major axis of the ellipsoid onto the plane whose normal is the cross-track direction.
Range wrt Secondary - CrossTrack	DistanceUnit	Real Number	The component of the relative position vector (i.e., primary position vector minus secondary position vector) in the secondary object's cross-track direction at the given time. The cross-track direction lies along the object's orbit normal.
Primary Roll	AngleUnit	Real Number	The roll angle for the primary object's ellipsoid at the given time. The roll angle locates the minor axis of the ellipsoid as a rotation about the major axis, with zero being aligned with the cross-track direction.
Primary SSC	Unitless	Integer	The SSC number of the primary object involved in the close approach event.
Range wrt Secondary - Tangential	DistanceUnit	Real Number	The component of the relative position vector (i.e., primary position vector minus secondary position vector) in the secondary object's tangential direction at the given time. The tangential direction lies along the object's inertial velocity.
Range wrt Secondary - Normal	DistanceUnit	Real Number	The component of the relative position vector (i.e., primary position vector minus secondary position vector) in the secondary object's normal direction at the given time. The normal direction completes a triad involving the tangential and cross-track directions and is akin to the radial direction.
Primary StringID	Unitless	Text	The string identifier of the primary object involved in the close approach event. If the object has no string identifier, then the value will be "Not Avail".
Range wrt Secondary - Radial	DistanceUnit	Real Number	The component of the relative position vector (i.e., primary position vector minus secondary position vector) in the secondary object's radial direction at the given time.
Range wrt Secondary - InTrack	DistanceUnit	Real Number	The component of the relative position vector (i.e., primary position vector minus secondary position vector) in the secondary object's in-track direction at the given time. The in-track direction completes a triad involving the radial and cross-track directions.
Primary vx	Rate	Real Number	The X component of the inertial velocity vector of the primary object at the given time.
Primary vy	Rate	Real Number	The Y component of the inertial velocity vector of the primary object at the given time.
Primary vz	Rate	Real Number	The Z component of the inertial velocity vector of the primary object at the given time.
Primary x	DistanceUnit	Real Number	The X component of the inertial position vector of the primary object at the given time.
Primary y	DistanceUnit	Real Number	The Y component of the inertial position vector of the primary object at the given time.
Primary Yaw	AngleUnit	Real Number	The yaw angle for the primary object's ellipsoid at the given time. The yaw angle locates from the tangential direction the projection of the major axis of the ellipsoid onto the plane whose normal is the cross-track direction.
Primary z	DistanceUnit	Real Number	The Z component of the inertial position vector of the primary object at the given time.
Primary: Time Since Epoch	TimeUnit	Real Number	The difference between the given time and the primary object's epoch.
Range Sigma	Unitless	Real Number	The value of the range between the objects measured at TCA, expressed in terms of sigma (i.e., the scale factor by which the combined covariance ellipsoid would need to be scaled to just touch the range vector).
Range Uncertainty	DistanceUnit	Real Number	The uncertainty in the range at the given time. The uncertainty is computed by treating the ellipsoid size and orientation as a measure of the position covariance for each object. The relative position covariance is then computed and projected onto the line of sight direction between the two objects to compute the value.
Velocity wrt Primary - CrossTrack	Rate	Real Number	The component of the relative inertial velocity vector (i.e., secondary inertial velocity vector minus primary inertial velocity vector) in the primary object's cross-track direction at the given time. The cross-track direction lies along the object's orbit normal.
Range	DistanceUnit	Real Number	The range (i.e., distance between the primary and secondary object) at the given time.
Relative Velocity	Rate	Real Number	The magnitude of the difference in the inertial velocities of the primary and secondary objects at the given time.
Velocity wrt Primary - Tangential	Rate	Real Number	The component of the relative inertial velocity vector (i.e., secondary inertial velocity vector minus primary inertial velocity vector) in the primary object's tangential direction at the given time. The tangential direction lies along the object's inertial velocity.
Velocity wrt Primary - Normal	Rate	Real Number	The component of the relative inertial velocity vector (i.e., secondary inertial velocity vector minus primary inertial velocity vector) in the primary object's normal direction at the given time. The normal direction completes a triad involving the tangential and cross-track directions and is akin to the radial direction.
Secondary NumberID	Unitless	Text	The number identifier of the secondary object involved in the close approach event. If the object has no number identifier, then the value will be "Not Avail".
Velocity wrt Primary - Radial	Rate	Real Number	The component of the relative inertial velocity vector (i.e., secondary inertial velocity vector minus primary inertial velocity vector) in the primary object's radial direction at the given time.
Velocity wrt Primary - InTrack	Rate	Real Number	The component of the relative inertial velocity vector (i.e., secondary inertial velocity vector minus primary inertial velocity vector) in the primary object's in-track direction at the given time. The in-track direction completes a triad involving the radial and cross-track directions.
Secondary SSC	Unitless	Integer	The SSC number of the secondary object involved in the close approach event.
Secondary StringID	Unitless	Text	The string identifier of the secondary object involved in the close approach event. If the object has no string identifier, then the value will be "Not Avail".
Velocity wrt Secondary - CrossTrack	Rate	Real Number	The component of the relative inertial velocity vector (i.e., primary inertial velocity vector minus secondary inertial velocity vector) in the secondary object's cross-track direction at the given time. The cross-track direction lies along the object's orbit normal.
Separation	DistanceUnit	Real Number or Text	The separation distance between the primary and secondary threat volumes at the given time. If the ellipsoids intersect, then the value will be "Intersect".
Time	DateFormat	Real Number	Time.
Velocity wrt Secondary - Tangential	Rate	Real Number	The component of the relative inertial velocity vector (i.e., primary inertial velocity vector minus secondary inertial velocity vector) in the secondary object's tangential direction at the given time. The tangential direction lies along the object's inertial velocity.
Velocity wrt Secondary - Normal	Rate	Real Number	The component of the relative inertial velocity vector (i.e., primary inertial velocity vector minus secondary inertial velocity vector) in the secondary object's normal direction at the given time. The normal direction completes a triad involving the tangential and cross-track directions and is akin to the radial direction.
Velocity wrt Secondary - InTrack	Rate	Real Number	The component of the relative inertial velocity vector (i.e., primary inertial velocity vector minus secondary inertial velocity vector) in the secondary object's in-track direction at the given time. The in-track direction completes a triad involving the radial and cross-track directions.
Velocity wrt Secondary - Radial	Rate	Real Number	The component of the relative inertial velocity vector (i.e., primary inertial velocity vector minus secondary inertial velocity vector) in the secondary object's radial direction at the given time.
Primary Ellipsoid - CrossTrack - Tangential	Unitless	Real Number	For a Covariance class threat volume, this is the correlation coefficient between the crosstrack and tangential position estimation errors for the primary vehicle.
Primary Ellipsoid - Normal - Tangential	Unitless	Real Number	For a Covariance class threat volume, this is the correlation coefficient between the normal and tangential position estimation errors for the primary vehicle.
Primary Ellipsoid - Normal - CrossTrack	Unitless	Real Number	For a Covariance class threat volume, this is the correlation coefficient between the normal and crosstrack position estimation errors for the primary vehicle.
Secondary Ellipsoid - CrossTrack-Tangential	Unitless	Real Number	For a Covariance class threat volume, this is the correlation coefficient between the crosstrack and tangential position estimation errors for the secondary vehicle.
Secondary Ellipsoid - Normal-Tangential	Unitless	Real Number	For a Covariance class threat volume, this is the correlation coefficient between the normal and tangential position estimation errors for the secondary vehicle.
Secondary Ellipsoid - Normal-CrossTrack	Unitless	Real Number	For a Covariance class threat volume, this is the correlation coefficient between the normal and crosstrack position estimation errors for the secondary vehicle.