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Naval Special Warfare Ultra High Frequency (UHF) Satellite Communications (SATCOM) Low Elevation Angle Antenna



TECHNOLOGY AREA(S): Battlespace, Electronics, Sensors

ACQUISITION PROGRAM: PMS340, Naval Special Warfare Program Office (Acquisition Program: SDV, SWCS) USSOCOM (PEO-M) DCS

OBJECTIVE: Develop a UHF SATCOM antenna with low elevation angle coverage to meet the operational needs of Naval Special Warfare.

DESCRIPTION: Naval Special Warfare (NSW) Forces employ the use of undersea mobility platforms including the in-service SEAL Delivery Vehicles (SDV) and two additional platforms that are currently under development. All of these platforms include the capability to communicate via UHF SATCOM. The current UHF SATCOM antenna used in the SDV fleet provides usable coverage only in the upward looking direction at elevation look angles greater than 45 degrees above the horizon. The SDV program office seeks the development of a Low Elevation Angle UHF Mast Antenna that will be used for UHF SATCOM communication on NSW Submersibles including the SDV and Dry Combat Submersibles (DCS). The antenna will be mast-mounted and will be a modular replacement with the existing UHF SATCOM antenna in use. It should be capable of being submerged in seawater to 125m. Prior to use, the antenna will be raised above the water line.

A mathematical approach is described to determine the required look angles (Ref. 1) to point an antenna to a geostationary communication satellite such as the Ultra High Frequency Follow-on (UFO) Satellite, which is used for military UHF SATCOM. Earth coverage analysis and simulation is described (Ref. 2) along with the difficulties of maintaining coverage with satellites for communication.

Physical Characteristics:

The existing UHF SATCOM antenna in use is housed in a government designed cylindrical radome made from G-10/FR4 fiberglass. The low angle antenna should be developed to fit within this exiting radome if possible. Novel and innovative ideas will be considered that exceed the existing radome envelope if they show promise for operating in a submerged marine environment and for successful integration into an NSW undersea mobility platform. This effort will reduce the life-cycle cost by 20-30% of future undersea mobility platforms through the development of a common solution that can be used on multiple platforms and ultimately Operations & Maintenance (O&M) costs during the sustainment phase for these platforms (Logistics, Maintenance, and Training).

Radome inner dimensions:


Diameter: 5.875 inches


Length: 23.49 inches

Radome exterior dimensions:


Diameter: 6.88 inches


Length: 26.95 inches


Maximum Weight (including radome): 35lbs



Elevation Coverage Pattern: +18 degrees to +45 degrees above the horizon


Radiation Pattern: Omni-directional in azimuth


Polarization: Right Hand Circular Polarized (RHCP)


Frequency Range: Ultra High Frequency Follow-On (UFO) uplink/downlink frequencies


Impedance: 50 ohms


Power Handling: 100W

The antenna will be characterized in a radio frequency (RF) measurement facility (Anechoic Chamber) or other suitable facility.

PHASE I: The company will develop a conceptual design of the Low Elevation Angle UHF SATCOM antenna that meets the technical requirements outlined in the description section above. The company will demonstrate the initial feasibility of this effort through software modeling and simulation. The Phase I Option if exercised, will include the initial design and capabilities description to build a prototype in Phase II.

PHASE II: Based on the results of Phase I effort and the Phase II Statement of Work (SOW), the company will develop a prototype antenna for evaluation and test it on an SDV or other available platform. Coordination to use a Government test platform will occur through NAVSEA PMS340. This effort will focus on integration into a government-supplied radome (if desired) or other efforts to make the antenna suitable for use in a submerged marine environment. The prototype antenna will be characterized in an anechoic chamber or other suitable antenna measurement facility prior to integration and testing on an SDV or other available platform in an operationally relevant environment. Success during testing will be characterized by making successful UHF SATCOM communications with a UFO satellite at an elevation between 18 and 45 degrees above the horizon. Evaluation results will be used to refine the prototype into a final design that will meet the desired performance goals. The Government will be required to coordinate the use of Department of Defense (DoD) communications assets and to identify funding for Government test platform and support.

PHASE III DUAL USE APPLICATIONS: The company will be expected to support the Navy in transitioning the Low Elevation Angle Antenna for use on undersea mobility platforms. The company will support the Navy for test, validation and certification in accordance with SDV and DCS specifications to certify and qualify the system for Navy use and for transition to operational undersea mobility platforms. Following testing and validation, the end design is expected to produce a product that provides improved low elevation angle UHF SATCOM coverage. The technology is expected to be integrated into the Dry Combat Submersible and SDV Programs. Private Sector Commercial Potential: This technology could be used in any situation where there is a need to reliably establish communications with low elevation angle satellites where antenna size is limited. While this particular effort is tailored to marine environments this could be used for land, aviation, and space applications as well.


  • Tomás Soler and David Eisemann, “Determination of Look Angles to Geostationary Communications Satellites” Journal of Surveying Engineering, Vol. 120, No. 3, August 1994, pp. 115-127
  • Shkelzen Cakaj, Bexhet Kamo, Algenti Lala, Alban Rakipi, “The Coverage Analysis for Low Earth Orbiting Satellites at Low Elevation” International Journal of Advanced Computer Science and Applications, Vol 5, No. 6, 2014, P. 6-10

KEYWORDS: Naval Special Warfare communications; SEAL Delivery Vehicle; UHF SATCOM Antenna; Satellite Communications; UFO Satellite; Low Elevation Angle UHF Mast Antenna

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