mshook with known

#orbit #determination
http://faculty.nps.edu/dad/orbital/halif.pdf
"General perturbation techniques SGP SGP BL on the contrary do not
use multiple time steps to transfer from a set of initial conditions to a nal
solution Rather general perturbation techniques implement an analytical in
tegration of the equations of motion to transform a set of initial conditions
directly to a nal solution However due to the complex nature of the equa
tions representing the physical models exactly integrable expressions are di
cult to obtain For this reason simplications approximations and truncations
are made to the equations of motion to obtain expressions which are integrable
These simplications however greatly reduce the accuracy attainable with gen
eral perturbation techniques In summary computational eciency is gained
at the cost of accuracy these techniques have typically been used for the bulk
of Space Commands operational missions due to the computational efficiency
advantages"

Michael Shook