getelem and evsgp4

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 action

getelem blueprint action

getelem 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

Computing Hubble Space Telescope’s location from TLEs

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