Columbia subject headings:
Artificial satellites--Orbits--Measurement.
Celestial mechanics.
Gravitation.
Perturbation (Mathematics)
Harvard subject headings:
Artificial satellites--Orbits--Measurement.
Celestial mechanics.
Gravitation.
Perturbation (Mathematics)
Princeton subject headings:
Artificial satellites--Orbits--Measurement.
Celestial mechanics.
Gravitation.
Perturbation (Mathematics)