Earth-fixed cell beam management for satellite communication system using dielectic lens-focused scanning beam antennas
US5736959A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 17, 1995 |
| Grant date | Apr 7, 1998 |
| Priority date | — |
| Expiry date | Apr 17, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B7/18552
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Earth-fixed cell beam management methods which may be employed to allocate beams generated by a constellation of low Earth orbit satellites (12) flying in orbits below geosynchronous altitudes are disclosed. These beams (19) are electronically steered so that they illuminate "Earth-fixed cells" (26) as opposed to "satellite-fixed cells." Beam steering apparatus using a spherical dielectric lens (106) is disclosed. In a system that employs satellite-fixed cells, the "footprint" of the beams propagated by a spacecraft defines the zone on the ground called a "cell" which is illuminated by the spacecraft. This satellite-fixed cell moves constantly as the spacecraft moves around the globe. In sharp contrast, an "Earth-fixed cell" (26) is a stationary region mapped onto the surface of the Earth (E) that has permanent fixed boundaries, just like a city or a state. Although the rapidly moving satellites (12) still shine their beams over the ground in rapidly moving footprints (16), the locations of the footprints at any given time do not determine the location of the unchanging Earth-fixed cells (26). The great advantage provided by using cells having boundaries that are fixed to an Earth-…
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