2.3 OPTIMIZATION OF THE ELLIPSO? AND ELLIPSO 2G? PERSONAL COMMUNICATIONS SYSTEMS

摘要

The innovative 17-satellite ELLIPSO? Personal Communication System is being developed to provide affordable personal telephonic and data communications using hand-held (cellular-type) terminals through a unique constellation that employs both elliptical and circular orbit communications satellites. This system uses the L-Band frequencies (1610 to 1621 MHz) for the hand-held or fixed user terminals. The use of inclined elliptical orbits permits the biasing of earth coverage by latitude, longitude and time of day so that satellite coverage can be matched to the market needs for particular geographical regions and their populations' daily work schedules. Circular equatorial orbits are used for continuous day and night coverage in the tropics and the Southern Hemisphere down to 55° South latitude. On September 26, 1997, MCHI filed an application with the Federal Communications Commission (FCC) for a new 26-satellite system named ELLIPSO 2G? to be operated in the 2 GHz band. This new system is also described, with emphasis on the orbital design and ephemerides of the array. A distinguishing feature of the newer system is the use of a combination of circular and elliptic orbits that will now bias total coverage towards daylight hours, in the tropics and the Southern Hemisphere. BOREALIS 2G? is similar to the basic BOREALIS? array except that it has three planes instead of two, giving extra daytime coverage. Both of these systems are atypical, from the classic constellation design methods (Walker, Beste or Ballard), in that they employ subconstellations of different periods and orbital characteristics (i.e., "hybrid" systems).