Airborne free space optical communication apparatus and method with subcarrier multiplexing
First Claim
Patent Images
1. Apparatus for communicating data in free space comprising:
- first and second communication terminals, each of said communication terminals further comprising;
an RF transmission module for receiving multiple data channels from a data source and processing said data channels to combine said data channels into an aggregate radio frequency subcarrier signal;
an optical transmission module for receiving said aggregate radio frequency subcarrier signal, impressing said subcarrier signal onto a laser optical carrier signal, and transmitting said laser carrier signal in free space;
an optical reception module for receiving a laser carrier signal from free space and extracting an aggregate radio frequency subcarrier signal therefrom;
an RF reception module for receiving said aggregate radio frequency subcarrier signal and separating said data channels therefrom; and
wherein said optical transmission and reception modules have means to acquire and track a remote communication terminal; and
a terminal controller connected to said RF transmission module and said RF reception module to control the processing of signals through said modules.
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Abstract
A free space laser communication system uses subcarrier multiplexing to prepare multiple data communication channels for impressing onto a laser carrier. Sending and receiving terminals mutually track to insure acquisition of the transmitted data signals.
13 Citations
25 Claims
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1. Apparatus for communicating data in free space comprising:
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first and second communication terminals, each of said communication terminals further comprising; an RF transmission module for receiving multiple data channels from a data source and processing said data channels to combine said data channels into an aggregate radio frequency subcarrier signal; an optical transmission module for receiving said aggregate radio frequency subcarrier signal, impressing said subcarrier signal onto a laser optical carrier signal, and transmitting said laser carrier signal in free space; an optical reception module for receiving a laser carrier signal from free space and extracting an aggregate radio frequency subcarrier signal therefrom; an RF reception module for receiving said aggregate radio frequency subcarrier signal and separating said data channels therefrom; and wherein said optical transmission and reception modules have means to acquire and track a remote communication terminal; and a terminal controller connected to said RF transmission module and said RF reception module to control the processing of signals through said modules. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. In a communication system of a local communication terminal and a remote communication terminal, a method for communicating data in free space comprising the steps of:
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receiving multiple individual channels of data from a data source at said local communication terminal; digitally processing said individual data channels for RF transmission; modulating said individual data channels on an intermediate frequency subcarrier signal; combining said individual data channels into an aggregate RF subcarrier signal; generating a communication laser carrier signal; impressing said aggregate RF subcarrier signal on said laser carrier signal; acquiring and tracking a remote communication terminal from said local communication terminal; transmitting said laser carrier signal in free space from said local communication terminal to said remote communication terminal; acquiring and tracking said local communication terminal from said remote communication terminal; receiving said laser carrier signal from free space from said local communication terminal; extracting said aggregate RF subcarrier signal from said laser carrier signal; decombining said aggregate RF subcarrier signal into a subcarrier signal containing said individual data signals; demodulating said intermediate subcarrier signal to obtain said individual data channels; and digitally processing said individual data channels for storage and use, and controlling the processing of the transmitted and received RF signal through a terminal controller connected to an RF transmission module and an RF reception module at each of said local and remote communication terminal. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25)
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Specification