SATELLITE COMMUNICATION SYSTEM

• US 3,676,778 A
• Filed: 08/20/1970
• Issued: 07/11/1972
• Est. Priority Date: 08/20/1970
• Status: Expired due to Term

• Current Assignee: Nippon Telegraph and Telephone Corporation
• Original Assignee: Yoshibumi Mori
• Inventors: Mori, Yoshibumi
• Primary Examiner(s): Griffin, Robert L.
• Assistant Examiner(s): Weinstein, Kenneth W.
• Application Number:
  US05/065,653
• Time in Patent Office: 691 Days
• Field of Search: 325/4,15,56,63,65,67,303,301,302,51,52,53,55 343/228,175
• US Class Current: 455/12.1
• CPC Class Codes: H04B 7/12 Frequency diversity
• CPC Class Codes: H04B 7/18515 Transmission equipment in satellites or space-based relays

Abstract

Attenuation caused by precipitation in a radio satellite communication system is minimized by monitoring transmission between the stations and the rate of precipitation at each station so that frequency bands having low attenuation to precipitation may be assigned to the stations in accordance with their rate of precipitation. A local monitor and controller provides switching information in response to the rate of precipitation to switch the transmission and reception respectively to transmitting and receiving frequency converters which operate in selected frequency bands.

Claims

1. A satellite communication system using selected frequency bands for transmission between a group of terrestrial stations and at least one satellite wherein one of said terrestrial stations is a central control station having communication paths to each of the other terrestrial stations via said satellite and a ground link, comprising;

means at said central control station for determining whether the rainfall at said terrestrial stations exceeds a maximum acceptable precipitation rate for communication and for transmitting to said other terrestrial stations switching control signals when the precipitation rate exceeds said maximum acceptable precipitation rate, each of said terrestrial stations comprising;

transmitting and receiving frequency converter means, carrier terminal equipment connected to said converters, each converter means including a plurality of converters tuned to a selected frequency band, precipitation collecting and measuring means for determining the incident rate of precipitation at said station and transmitting an output indication thereof to said control station, and means responsive to said control signals for switching the station transmission and reception from converter means having a frequency band attenuated by said precipitation to converter means having a frequency band less affected by said precipitation.

2. A satellite communication system as in claim 1 wherein each of said stations includes a back-up station located at a position spaced from its associated terrestrial station to have a small precipitation correlation therewith and means at each station for switching to said back-up station.

3. A satellite communication system as in claim 1 wherein each of said terrestrial stations further comprises a plurality of intermediate frequency modulators and demodulators each operating at a different frequency band and interconnecting, respectively, said carrier terminal equipment and an associated receiving and transmitting converter.

4. A satellite communication system as in claim 3 wherein said means for switching is a pair of diode matrices each having outputs respectively connected to said transmitter converters and to said receiver converters and each having inputs respectively connected to said modulators and to said demodulators.