JSC Files on Predator Frequency Bands I

April 18, 2010

Joint Spectrum Center (JSC)

The Joint Spectrum Center (JSC), a field activity of the Defense Information Systems Agency (DISA), was established to provide advice and assistance on all matters regarding the electromagnetic battlespace. Support is provided to the Secretary of Defense, the Joint Staff, the military departments, combatant commands, defense agencies, and other agencies of the US Government. The JSC works closely with the Joint Staff, Director for Command, Control, Communications, and Computer Systems, and the Assistant Secretary of Defense for Network and Information Integration on spectrum matters.
Direct support is provided to the Unified Commands and Joint Task Force Commanders on electromagnetic battlespace issues, including spectrum management and electronic warfare deconfliction. Support to DoD components and the US Government is provided through a sponsorreimbursed electromagnetic compatibility (EMC) program that provides EMC analyses for specific projects.

Predator MAE UAV

According to the Air Force, the Predator is a “Joint Forces Air Commander-owned theater asset for reconnaissance, surveillance and target acquisition in support of the Joint Force commander.” Because the Predator is unmanned it is suitable for deployment in “moderate risk areas”, unsecured air space, “open ocean environments, and biological or chemical contaminated environments.” In addition, as the October 2001 attacks in Afghanistan have illustrated, the Predator can now perform a search and destroy mission with no apparent risk to US military personnel.

The Predator system was designed to provide constant intelligence, surveillance, and reconnaissance to US strategic and tactical forces. This system is operated by the 11th and 15th reconnaissance squadrons at Indian Springs Air Force Auxiliary Field in Nevada.

Technical Specifications

The Predator Medium Altitude Endurance (MAE) Unmanned Aerial Vehicle (UAV) was developed as an Advanced Concept Technology Demonstration (ACTD) from January 1994 to June 1996. The Predator system is composed of three parts: the air vehicle [a derivative of the Gnat 750] with its associated sensors and communications equipment, the ground control station (GCS), and the product or data dissemination system. One Predator system has four air vehicles with sensors and data links, one Ground Control Station (GCS), and one Trojan Spirit II SATCOM system.

The air vehicle is a mid-wing monoplane with a slender fuselage housing the payload and fuel, a high aspect ratio wing, and inverted-V tails. A four-cylinder Rotax engine that requires 100-octane aviation gas powers the air vehicle. According to the The Air Force Fact Sheet the RQ-1A needs 5,000 by 125 feet of a hard surface runway. In addition, the vehicle requires line-of-sight with the GCS and all support components for the Predator system must be at a single location.

The air vehicle can be broken-down into six primary parts and packed into a container known as the “coffin.” The satellite communication system consists of a 20-foot satellite dish and its associated support equipment. This satellite system is especially important because is provides the Predator aerial vehicle to communicate beyond line-of-sight with its GCS. The benefits of this component system are that it can be easily deployed around the world.

The sensors include an electro-optic/infrared (EO/IR) Versatron Skyball Model 18 with a zoom lens and a spotter lens, and a Westinghouse 783R234 synthetic aperture radar (SAR). The ground control station consists of a pilot position and a payload operator position, which are interchangeable, a Data Exploitation, Mission Planning and Communications (DEMPC) position where imagery is annotated and initially exploited, and a SAR workstation. The GCS is housed in a 30 ft x 8 ft x 8 ft commercial van.

The current data dissemination is through the TROJAN SPIRIT II (TS II), a Special Compartmented Information (SCI) satellite communications (SATCOM) system that allows transmission and receipt of secure voice and National Imagery Transmission Format (NITF) imagery data. The TS II physically consists of two High Mobility Multi-purpose Wheeled Vehicles (HMMWVs) and two trailer-mounted SATCOM antennas. Sensor imagery is disseminated from the Predator ground control station via the Trojan Spirit II SATCOM system using the Joint Deployable Intelligence Support System (JDISS) and the Joint Worldwide Intelligence Communications System (JWICS). Live video is disseminated through the Joint Broadcast System (JBS).

Joint Spectrum Center

216 Sweeney Blvd, Room 109
Langley AFB, VA 23665

November 2003

Prepared by
Steve Bonter, Young Kim, Jonathan Timko, and Thu Luu
Alion Science and Technology

Distribution Authorized to DoD Components Only; Operational Use; November 2003. Other requests for this
document shall be referred to ACC/DR-UAV or JSC/J8.

The JSC conducted an electromagnetic compatibility (EMC) analysis to determine the potential for electromagnetic interference (EMI) between the Predator UAV LOS Data Link Terminal and the communications-electronics (C-E) environment near ISAFAF for four candidate frequency bands: 4.4-4.94, 5.25-5.85, 14.4-14.83, and 15.15-15.35 gigahertz (GHz). Since integration of Tactical Common Data Link (TCDL) terminals into the UAV and ground data terminal (GDT) is planned, this analysis also included determining the potential for EMI between the TCDL configured Predator and the C-E environment near ISAFAF for the 14.4-14.83 and 15.15-15.35 GHz frequency bands.
Each frequency band had a potential for EMI between the terminals and various C-E systems in the environment. Environmental systems analyzed included, but were not limited to: radar systems (fixed and mobile), terrestrial microwave links, telemetry systems, satellite downlink systems, and radio astronomy (RA) telescopes.
Where potential EMI was noted, mitigation techniques were recommended. Analysis of the interactions where the RL transmitter was the source of the interference to terrestrial microwave links indicates that the 14.4-14.8 GHz band RL transmitter may cause interference to select transportable microwave links.
It is recommended that RL transmitter operations be coordinated with the Department of Energy. For six Department of Justice (DOJ) fixed microwave links, it is recommended that there be a minimum frequency separation of 11 megahertz (MHz) between the RL transmitter and fixed microwave link. All of the DOJ microwave links operate in the upper portion of the 4400-4940 MHz band, and therefore it is recommended that the RL for this band be located in the lower portion of this band below 4749 MHz.
For RA systems, frequency separation is required to preclude interference to the very long baseline array at Owens Valley Radio Observatory, Owens Valley, CA. There were no interactions involving radar systems, telemetry systems, and satellite downlink systems that resulted in predicted EMI.

DoD Leaks: Download the file!

Joint Spectrum Center

Prepared for
Air Combat Command UAV Special Mission Office (ACC/DR-UAV)
November 2003
Prepared by
Steve Bonter and Clifford Price
Alion Science and Technology
Distribution authorized to US Government agencies only; Operational Use; November 2003.

The Predator Unmanned Aerial Vehicle (UAV) line-of-sight command link and return link frequency assignments are authorized for simultaneous operations of four General Atomics Aeronautical Systems Incorporated Predator air vehicles at Indian Springs Air Force Auxiliary Field (ISAFAF). With increased operational tempo of RQ-1/MQ-1 Predator and the introduction of MQ-9 Hunter-Killer (Predator B®) operations, requirements have been identified for simultaneous operations of seven
Predator air vehicles at IAFAF. As part of the RQ-1/MQ-1/9 beddown of communications architecture, ACC/DR-UAV requested the Joint Spectrum Center to perform electromagnetic compatibility (EMC) analyses to ensure EMC with unlicensed devices operating under the Code of Federal Regulations (CFR), specifically CFR 47 Parts 15.245, 15.247, 15.249, 15.401, and Part 90.

Systems representative of CFR 47 Part 15 and Part 90 devices that operate in the 5250-5850 megahertz band were identified for analysis as follows:
• 15.245 industrial point-to-point microwave
• 15.247 residential indoor and industrial outdoor radio local area network (RLAN)
• 15.249 outdoor video surveillance
• 15.401 outdoor industrial unlicensed national information infrastructure (U-NII)
• 90 outdoor industrial dedicated short range communications (DSRC) systems
A first cull noise-limited analysis was performed. A detailed interference-limited analysis was performed for cases where electromagnetic interference (EMI) was predicted. A signal-to-noise ratio threshold (S/NT) was determined for each modulation. Signal-to-interference-plus-noise (S/(I+N)) was calculated. S/(I+N) was compared to S/NT to quantify interference potential.

No EMI problems were identified for the analyzed operational location. Operations in closer proximity to residential and industrial areas may cause interference to potential victim systems analyzed in this report.

DoD Leaks: Download the file!


Predator UAV C-Band Data Link Site-Independent Emc With 5-Ghz 47 C.F.R. Part 15 And Part 90 Devices

Prepared for
Office Of The Assistant Secretary Of Defense (OASD)
Networks and Information Integration Spectrum Office
May 2004

Prepared by
Steve Bonter
Alion Science and Technology

Distribution authorized to DoD Components only; Operational Use; May 2004.
Other requests shall be referred to OASD/NII or JSC/J8.

The Predator Unmanned Aerial Vehicle (UAV) line-of-sight (LOS) command link and return link frequency band is allocated to aeronautical radionavigation, maritime radionavigation, meteorological aids, and radiolocation services. The Predator LOS links are in the aeronautical mobile service and are considered out-of-band. As such, Predator LOS link spectrum supportability is on a noninterference basis.

The Code of Federal Regulations (C.F.R.) authorizes unlicensed radio frequency (RF) devices in the frequency bands 5150 – 5350 MHz and 5725 – 5925 MHz. These RF devices utilize the same portion of the RF spectrum as the Predator LOS links, and they are being fielded at an accelerated rate. The Office of the Assistant Secretary of Defense for Networks and Information Integration requested that the DoD Joint Spectrum Center determine the electromagnetic compatibility issues associated with Predator UAV LOS data links and unlicensed devices operating under the C.F.R. in the same electromagnetic environment.

A first cull noise-limited analysis was performed; where electromagnetic interference (EMI) was predicted, a detailed interferencelimited analysis was performed. For any remaining cases of potential EMI, possible mitigation techniques were identified. The data in this report was current as of January 2004.

Electromagnetic Compatibility Analysis of the Predator UAV Line-Of-Sight Data Link Terminal With The Communications-Electronics Environment At Indian Springs Air Force Auxiliary FieldPredator Uav C-Band Data Link Emc With 5-Ghz Cfr 47 Part 15 And Part 90 Devices

DoD Leaks: Download the file!


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