Fiber optic radio frequency distribution system

• US 7,715,722 B1
• Filed: 01/27/2006
• Issued: 05/11/2010
• Est. Priority Date: 01/27/2006
• Status: Active Grant

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Pobiel, Joseph, Hoke, Terry L.
• Primary Examiner(s): Liu; Li
• Application Number:
  US11/340,936
• Time in Patent Office: 1,565 Days
• Field of Search: 398/19, 398/28, 398/33, 398/45, 398/115, 398/116, 398/58, 398/66, 455/3, 455/39, 455/73, 455/562, 455/561, 455/562.1
• US Class Current: 398/115
• CPC Class Codes: H04B 10/25758 between a central unit and a single remote unit by means of an optical fibre

Abstract

A scalable, flexible, automated radio frequency distribution system (FORFDS) employs fiber optics to eliminate the need for metallic/coaxial type interconnections between onboard and fixed-site radios and antennas. Key elements of the FORFDS may include, for example, 1) electrical to optical conversion (and vice versa) of RF signals, 2) optical switching, 3) automated control and monitoring, including Ethernet interfaces, and 4) high density packaging. The system is compatible with JTRS (2 MHz to 2000 MHz), is scalable and cost effective (no longer in the laboratory or concept high cost ranges), compared with known technologies.

Claims

1. A fiber optic RF distribution system (FORFDS), comprising:

a plurality of fiber optic cables;

a radio system;

an antenna system;

a plurality of electrical to optical converters coupled to the radio system and configured to convert analog signals to optical signals;

a plurality of electrical to optical converters coupled to the antenna system and configured to convert analog signals to optical signals;

a plurality of optical to electrical converters coupled to the radio system and configured to convert optical signals to analog signals;

a plurality of optical to electrical converters coupled to the antenna system and configured to convert optical signals to analog signals;

at least one optical switch co-located with the antenna system and configured to selectively interface the optical signals with optical to electrical converters selected from the plurality of optical to electrical converters coupled to the radio system and the antenna system, and further configured to interface the analog signals with electrical to optical converters selected from the plurality of electrical to optical converters coupled to the radio system and the antenna system, such that low level analog signals can be transferred accurately between the radio system and the antenna system via at least one fiber optic cable selected from the plurality of fiber optic cables in response to a control signal;

automated control and monitoring systems configured to monitor operation of the at least one optical switch and to generate the control signal, such that the at least one optical switch selectively passes an analog signal between a desired portion of the radio system and a desired antenna via at least one fiber optic cable selected from the plurality of fiber optic cables;

at least one system module that is configured to provide signal filtering and conditioning such that analog signals can pass accurately between the radio system and the antenna system; and

a second optical switch co-located with the radio system;

wherein the automated control and monitoring systems comprise at least a network manager system associated with the radio system and at least a local control system associated with the antenna system.

2. The FORFDS according to claim 1, wherein the optical switch is configured as a photonic matrix switch.

3. The FORFDS according to claim 1, wherein the radio system comprises at least one radio selected from the group consisting of a joint tactical radio, and a digital mode radio.

4. The FORFDS according to claim 1, wherein the at least one system module is selected from the group comprising a high frequency module, a very high frequency module, a ultrahigh frequency module, a multiband module, and a RF module, and

wherein the at least one system module provides signal filtering and conditioning in order to achieve a desired Noise Figure (NF) and a desired Spurious Free Dynamic Range (SFDR) between the radio system and the antenna system.

5. A fiber optic RF distribution system (FORFDS), comprising:

at least one radio system coupled via a plurality of electrical-to-optical and optical-to-electrical converters and at least one fiber optic cable to at least one antenna system remote from the radio system;

means for controlling selection of the plurality of converters, such that a low level analog signal can be transferred accurately between the at least one radio system and the at least one antenna system via the at least one fiber optic cable;

means for monitoring and controlling operation of at least one optical switch, such that the at least one optical switch selectively passes the low level analog signal between a desired portion of the at least one radio system and a desired antenna via the at least one fiber optic cable; and

means for filtering and conditioning at least one analog signal selected from the group comprising a high frequency signal, a very high frequency signal, a ultrahigh frequency signal, a multiband signal, and a RF signal;

wherein the means for controlling selection of the plurality of converters comprises an optical switch co-located with the at least one antenna system;

wherein the means for monitoring and controlling operation of the at least one optical switch comprises at least a network manager system associated with the at least one radio system and at least a local control system associated with the at least one antenna system;

wherein the at least one radio system is remotely located from the at least one antenna system to create a network centric architecture devoid of metallic cabling;

wherein the optical switch is configured as a photonic matrix switch;

wherein the at least one radio system comprises at least one radio selected from the group consisting of a joint tactical radio, and a digital mode radio; and

wherein the means for filtering and conditioning is configured to provide signal filtering and conditioning to achieve a desired Noise Figure (NF) and a desired Spurious Free Dynamic Range (SFDR) between the at least one radio system and the at least one antenna system such that analog signals can pass accurately between the at least one radio system and the at least one antenna system.

6. The FORFDS according to claim 5, wherein the at least one radio system is associated with a seagoing vessel.

7. The FORFDS according to claim 5, wherein the at least one radio system is associated with a fixed-site location.

8. A method of analog signal communication comprising:

providing a fiber optic RF distribution system coupling a radio system with an antenna system via at least one optical switch and a plurality of electrical-to-optical and optical-to-electrical converters, wherein the antenna system is remote from the radio system to create a network centric architecture;

transferring low level analog signals accurately between the radio system and the antenna system via the fiber optic RF distribution system;

controlling selection of the plurality of electrical-to-optical and optical-to-electrical converters, such that the low level analog signal can be transferred accurately between the radio system and the antenna system via a fiber optic cable;

monitoring and controlling operation of the at least one optical switch, such that the at least one optical switch selectively passes the low level analog signal between a desired portion of the radio system and a desired antenna via the fiber optic cable;

wherein controlling selection of the plurality of electrical-to-optical and optical-to-electrical converters comprises an optical switch co-located with the antenna system;

wherein monitoring and controlling operation of the at least one optical switch comprises a network manager system associated with the radio system and a local control system associated with the antenna system;

wherein the radio system comprises technology selected from the group consisting of joint tactical radio technology and digital mode technology;

wherein transferring low level analog signals accurately between the radio system and the antenna system via the fiber optic RF distribution system comprises conditioning and filtering the low level analog signals to achieve a desired Noise Figure (NF) and a desired Spurious Free Dynamic Range (SFDR) between the radio system and the antenna system.

9. The method according to claim 8, wherein the analog signal levels are less than 0 dBm in a range between about 2 MHz and about 2 GHz.