The last few decades have seen extensive use of polar/near-polar and inclined orbits for the purposes of remote sensing, surveillance, meteorology and scientific research. Highly-inclined LEO and MEO constellations are also being implemented for global communications. Tropical humid countries around the equatorial belt, however, are at great disadvantages in the case of highly-inclined orbits, in terms of short and infrequent passes. This paper evaluates the use of Equatorial Low-Earth Orbits (ELEO) to provide highly-improved coverage patterns for areas at or near the equator. It is shown that a single satellite in ELEO can provide more than 12 passes per day over a point at or near the equator, all of them being almost overhead, thus a great advantage in terms of communication time and required transmitted power and the corresponding issues. It is also shown that for a 1000 Km ELEO, an overhead pass will provide more than 16-17 minutes of communication time with a sufficient value of elevation angle i.e. ¿ ¿ 3-5° degrees. Thus, a number of 6-7 satellites would be sufficient to provide continuous 24-hour coverage for all the areas at or near the equator, namely at latitudes as high as -30 to 30 degrees, well above the tropic of Cancer and tropic of Capricorn which translates into complete coverage of the central African continent and coverage of more than 90% of the whole African continent.
Equatorial Low-Earth Orbits for Missions Concerning the African Continent
2008-03-01
354430 byte
Conference paper
Electronic Resource
English
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