Multiplex communications – Communication over free space – Repeater
Reexamination Certificate
1999-11-02
2003-08-12
Kincaid, Lester G. (Department: 2685)
Multiplex communications
Communication over free space
Repeater
C455S012100
Reexamination Certificate
active
06606307
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates in general to satellite communications, and, in particular, to techniques for fully utilizing the bandwidth capabilities of space assets.
2. Description of Related Art
Communications satellites are in widespread use. The communications satellites are used to deliver television and communications signals around the earth for public, private, and military uses.
The primary design constraints for communications satellites are antenna beam coverage and radiated Radio Frequency (RF) power. These two design constraints are typically thought of to be paramount in the satellite design because they determine which customers on the earth will be able to receive satellite communications service.
Satellite weight is also a factor, because launch vehicles are limited as to how much weight can be placed into orbit. Lower orbits, such as Low Earth Orbit (LEO), and Medium Earth Orbit (MEO), also known as Intermediate Circular Orbit (ICO) do not require as large of a launch vehicle per pound of satellite weight, but LEO and MEO satellites are also weight limited. Since launch costs are large, the satellite must be utilized as much as possible in order to make the satellite commercially viable. If there is not enough usage of the satellite, the satellite manufacturer or the satellite owner will not be able to recoup the financial outlay for the satellite, thus decreasing the available worldwide communications links.
Proper selection of beam coverage, radiated RF power, and weight do not guarantee that the satellite services, also known as “space assets,” are utilized in an efficient or complete manner. For example, the fact that a satellite transponder channel has enough radiated RF power supplied by an RF amplifier, and the satellite has a proper antenna to direct the transponder channel to a given area on the earth's surface, does not guarantee full utilization of the transponder signal. The bandwidth of the signal must be reviewed, analyzed, and configured to fully utilize the transponder channel to maximize the usage of the space asset, i.e., the transponder channel.
From the foregoing, it can be seen that there is a need in the art for techniques to review, analyze, and configure a satellite to fully utilize the services provided by the satellite. It can also be seen that there is a need in the art to provide more complete utilization of space assets without dramatically increasing weight. There is also a need in the art to provide more complete utilization of space assets without dramatically increasing the cost of manufacturing and operating a satellite.
SUMMARY OF THE INVENTION
To overcome the limitations in the prior art described above, and to overcome other limitations that will become apparent upon reading and understanding the present specification, the present invention discloses methods for operating a satellite constellation that utilize spatial diversity and directional gain antennas at ground terminal locations to provide multiple data rate services on a single frequency channel.
One method comprises receiving a signal at a first and second satellite in the satellite constellation from a first communications device. A communications channel at a first frequency from the first satellite is used to communicate with the first communications device. A signal from a second communications device is received at the second satellite at the first frequency, and the second satellite is used to communicate with the second communications device at the first frequency without substantially interfering with the communications with the first communications device.
An object of the present invention is to provide techniques to review, analyze, and configure a satellite to fully utilize the space assets of the satellite. Another object of the present invention is to provide more complete utilization of space assets without dramatically increasing weight. Still another object of the present invention is to provide more complete utilization of space assets without dramatically increasing the cost of manufacturing and operating a satellite.
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Chang Donald C. D.
Chang Ming U.
Cheng David C.
Novak, III John I.
Taormina Frank A.
Duraiswamy V. D.
Hughes Electronics Corporation
Kincaid Lester G.
Mehrpour Naghmeh
Sales M. W.
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