Blueprint action getelem
can be used to parse TLEs into a representation that can be used to compute state.
getelem
Abstract
Parse the “lines” of a two-line element set, returning the elements in units suitable for use in SPICE software.
getelem blueprint actiongetelem
returns a STwoLineElements
value, as Elems
.
ev2lin
Accepts a STwoLineElements
value as input. This is the return value of getelem
. The ev2lin
action computes a state variable and returns it as a SStateVector
value, State
.
Note that ev2lin is deprecated, the new method is evsgp4
.
getgeophs
This action returns a STLEGeophysicalConstants
value. ev2lin
requires this value, which is obtained by getgeophs
from kernel pool variables, as input. Earth’s geophysical constants are located in Kernel data file geophysical.ker
located here.

Computing Hubble Space Telescope’s location from TLEs