Data Provider Groups | Data Provider Elements

AER Data

Provides azimuth, elevation, and range related information for the relative position vector between the base object and the target object. The information is available in a variety of coordinate axes.

Reference Frames in AER Reports

AER reports for accesses are based on a default local coordinate system for every type of STK object. If the AER Report is based on a sensor, then the coordinate frame of the parent object is used.

For facilities, places, and targets the local coordinate system is LH.

• Azimuth is referenced to X, positive towards Y (clockwise from above).
• Elevation is referenced to X-Y plane, positive along negative Z.

For aircraft, ships, and ground vehicles the local coordinate system is VVLH CBF (Central Body Fixed).

• Azimuth is referenced to X, positive towards Y (clockwise from above).
• Elevation is referenced to X-Y plane, positive along negative Z.

For satellites and missiles the local coordinate system is VVLH CBI (Central Body Inertial).

• Azimuth is referenced to X, positive towards Y.
• Elevation is referenced to X-Y plane, positive along negative Z.

where,

LH (Local Horizontal)

X axis = constrained toward local north
Y axis = local east
Z axis = aligned with local geodetic nadir

VVLH (Vehicle Velocity, Local Horizontal)

X axis = constrained toward velocity vector
Y axis = perpendicular to X and Z.
Z axis = aligned with geocentric nadir

How Azimuth and Elevation are Defined

The following frames are used in defining azimuth (Az) and elevation (El):

Vehicle Velocity Local Horizontal (VVLH) coordinate system

Local Horizontal (LH) coordinate system

Topocentric coordinate system

Topocentric System

VVLH & LH Systems

For more information, see Access Tool.

Available for these objects: Access

Type: Time-varying data.

Availability: Reports | Graphs | Dynamic Displays | Strip Charts

Data Provider Groups

Name	Description
Default	Axes used to express the results by default (i.e., when no specific axes have been chosen by the user). The base object class type determines which axes are used by default.
VVLH CBI	Axes aligned with the VVLH axes based on the CBI velocity of the base object. Elevation is measured positive toward the -Z-axis.
VVLH CBF	Axes aligned with the VVLH axes based on the CBF velocity of the base object. Elevation is measured positive toward the -Z-axis.
BodyFixed	Axes aligned with the body axes of the base object. Elevation is measured positive toward the +Z-axis.
NorthEastDown	Axes aligned with North (X), East (Y), and Down (Z) of the detic subpoint of the base object (i.e., the detic projection of the base object's position to its central body's ellipsoid. Elevation is measured positive toward the -Z-axis (i.e, Up).

Data Provider Elements

Name	Dimension	Type	Description
Access Number	Unitless	Integer	The number of the current access interval from the list of access intervals.
Time	Date	Real Number or Text	Time.
Azimuth	Longitude	Real Number or Text	Angle measured from the X-axis of the direction of the relative position vector, positive about the axis used to measure positive elevation.
Elevation	Angle	Real Number or Text	Angle measured from the XY-plane to the direction of the relative position vector.
Range	Distance	Real Number	Magnitude of the relative position vector. The relative position vector reflects the access settings for light time delay, aberration, and refraction.
AzimuthRate	AngleRate	Real Number	The rate of change of azimuth.
ElevationRate	AngleRate	Real Number	The rate of change of elevation.
RangeRate	Rate	Real Number	The rate of change of range.
Path Delay	Time	Real Number	The range divided by the speed of light.
From Precision Pass	Unitless	Real Number	The precision pass number of the base object. Applicable only for Satellites.
To Precision Pass	Unitless	Real Number	The precision pass number of the target object. Applicable only for Satellites.
From Precision Path	Unitless	Real Number	The precision path number of the base object. Applicable only for Satellites.
To Precision Path	Unitless	Real Number	The precision path number of the target object. Applicable only for Satellites.
Strand Name	Unitless	Text	Lists the names of the objects in the best strand of the stored best strands. The object names are reported as truncated paths, without class names, separated by “to".
Local Hour Angle	Angle	Real Number or Text	The local hour angle of the target object with respect to the base object. The local hour angle is the angle from the X-axis of the central body Fixed axes to the projection of the relative position vector into the XY-plane of the central body Fixed axes.