Orbit selection for optimum satellite system performance

In the case of orbital altitudes between approximately 3000 to 20,000 nmi (medium altitude), it is possible to conduct an especially simple orbit analysis. Questions of orbit analysis are explored and an orbit selection based on visibility statistics is considered. Various approaches are discussed to optimize the coverage of satellite systems. The average elevation angle criterion is found to be inadequate. It does not discriminate strongly against low elevation angles. Five and six satellite combinations of Molniya and synchronous systems are shown to offer excellent elevation angle statistics in maritime areas when the satellites are placed to minimize the average cosecant elevation angle. A new statistical measure is introduced for cost effectiveness comparisons of any constellations. The most desirable systems are discussed.