Chain: Event Data
Reports certain data at defined event
times during each interval, for strands consisting of only two
objects. The 'From-object' is the first object listed in the
strand; the 'To-object' is the second object listed. Values are
reported for each strand access interval that lies within the
requested report intervals. The azimuth and elevation angles are
reported with respect to a frame determined by the first object.
The azimuth angle is the angle from the X axis (positive about the
Z-axis) to the projection of the apparent relative position vector
into the XY plane. The elevation is the angle of the apparent
relative position vector from the XY plane, with positive angles
being used when the vector has a negative Z component. When the
first object is a Facility, Place, or Target, the XYZ frame is
Topocentric (X aligned with North, Y aligned with East, and Z
aligned with the detic nadir of the detic subpoint of the first
object with respect to its central body). When the first object is
a Satellite, Missile, or LaunchVehicle, the XYZ frame is CbiVVLH
(inertial vehicle velocity local horizontal frame, with the Z axis
aligned with the anti-radial direction and the X axis constrained
toward the inertial velocity direction). When the first object is
an Aircraft, GroundVehicle, or Ship, the XYZ frame is CbfVVLH
(fixed vehicle velocity local horizontal frame, with the Z axis
aligned with the anti-radial direction and the X axis constrained
toward the central body fixed velocity direction) when the central
body fixed velocity is not close to zero; when the velocity is
close to zero, then the Topocentric frame is used. When the first
object is a Sensor, then the frame is determined by its parent
object as described above.
Type: Interval data
Availability: Reports
Name |
Description |
AOS
|
The event time is the start time of the interval (a.k.a.
acquisition of signal). |
LOS
|
The event time is the end time of the interval (a.k.a. loss of
signal). |
TME
|
The event time is the time of maximum elevation during the
interval. |
TCA
|
The event time is the time of closest approach (i.e., minimum
range) during the interval. |
STK Programming Interface 11.0.1