A satellite that orbits the Earth on a course that takes it over (or near) the North and South Pole.
An artificial satellite that has an orbit that travels over the vicinity of the geographic poles; it usually revolves in its orbital plane around the earth at an altitude ranging from 400 to 1200 km, passing over essentially all points on earth daily as the earth rotates under the plane of the satellite. Contrast with geosynchronous satellite.
A satellite that provides complete coverage of the Earth's surface twice per day. It normally orbits 800 to 900 km above the Earth and has a field of view that is about 2400 km, centered on the orbit path.