propTLE

MATLAB

[G ECI] = propTLE(TLE,startTime,elapsedTime,[GEOM]);
[pos vel time] = propTLE(TLE,startTime,elapsedTime);

Description

Returns a geometry structure of ECF positions and velocities by propagating the input TLE set using the NORAD SGP4/SDP4 propagator. This code runs much faster when using the calling sequence with three outputs: matrices for position and velocity in ECI coordinates and time.

Parameters

Parameters	Description
TLE [struct]	TLE structure from TLEExtract
startTime [date]	Start time (in UT1) - can be any acceptable Matlab date format. If empty, startTime is the TLE Epoch Date.
elapseTime [vector]	Time vector for propagation from startTime or length of time to propagate from startTime (sec)
GEOM [struct/list]	(Optional) Geometry structure defining observer position and velocity as from GeomStruct or a list of (RPLLA,[VPLLA],[RE]). Defaults to LLA position and velocity equal [0 0 0].
RPLLA [vector]	(Optional) Observer LLA position [Lat Long Alt]
VPLLA [vector]	(Optional) Observer LLA velocity [Vxy Heading Vz]
RE [scalar/vector]	(Optional) Earth radius, defaults to PhysicalConst('reequator','repole')

Return Values

Return Values	Description
G [struct]	Array of ECF geometry structures
ECI [struct]	Contains the satellite position, velocity, and time data
ECI.pos [array]	X, Y, Z position data (m)
ECI.vel [array]	X, Y, Z velocity data (m/s)
ECI.time [array]	Time required for conversion from ECI to ECF (sec)
pos [array]	X, Y, Z position data in ECI coordinates (m)
vel [array]	X, Y, Z velocity data in ECI coordinates (m/s)
time [array]	Time required for conversion from ECI to ECF (sec)

References

Hoots F., Roehrich R., Spacetrack Report No.3, 1980