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Expendable Active RF Technology for Helicopters (EARTH)




OBJECTIVE: To develop an expendable active RF radar countermeasure that can be deployed from rotary wing aircraft and effective at defeating threats independently or in conjunction with low powered directed energy RF countermeasures.

DESCRIPTION: The Army is interested in novel RF countermeasures compatible with the limited size, weight, and power (SWaP) of rotary wing aircraft to counter advances in radar threat systems as a replacement for traditional passive radar countermeasure expendables. The radar countermeasure would be expected to provide a false radar target through active jamming from an expendable. Future expendable technology concepts should consider small power source and aerodynamics that could support enough flight/transmit time and coverage for the platform to maneuver or eliminate the threat. Deployment of this type of countermeasure would be a low weight and low cost alternative and/or supplement to traditional countermeasure systems against radar and RF guided weapons. Current RF expendables on Army Rotary wing are a simple chaff, basically metallic shavings that create a false radar signature in an attempt to either hide the platform or distract an active radar system. This topic is expected to replace chaff by providing active transmission of countermeasure waveforms through application of digital RF memory countermeasure techniques from an expendable.

Developed expendable size constraints are 1 inch x 1 inch x 8 inches (length). Furthermore the expendable should be activated via an impulse cartridge (also known as squib), examples include OMI-M796, and OMI-BBU-355. Objective weight of the expendable is below 200g and must be operable in all weather conditions and temperatures from -45 to 75 degrees Celsius. Preliminary output power objective is 10W average power and a frequency range from 2-18 GHz. Active emission times is expected to be between 15 and 30 seconds from ejection, giving the equipped rotor craft time to mask it’s signature with terrain or other countermeasure capability.

PHASE I: Provide trade analysis and develop overall system design that includes transmitter circuit design and aerodynamics flight model accounting for rotor wash of the aircraft. Expected deliverable from Phase I would include a white paper describing the engineering trade space for potential system designs, notional circuit designs and an analysis of the viability of the aerodynamic flight model.

PHASE II: Develop and demonstrate expendable prototype with realistic power source suitable for long shelf life. Conduct testing to prove feasibility of flight time in operational conditions. Phase II deliverables would include a detailed design of prototype system, including bill of materials and layout, as well as a white paper focused on potential a long shelf life power supply solution.

PHASE III DUAL USE APPLICATIONS: At conclusion of Phase III, the expendable would be an additional asset for employment by military rotary wing aircraft by providing countermeasure effects against advanced radar threat systems. Installation and operation would be compatible with current expendable dispensing systems. Information on specifications of existing expendable dispenser system can be found at BAE Systems reference the AN/ALE-47 Dispenser System. The most likely transition of this technology would be to Program Manager (PM) Aircraft Survivability Equipment (ASE) and/or PM Close Combat Systems (CCS) for fielding on Army helicopters. The flight dynamics of the expendable could be modified to suit high-altitude commercial jetliner for self-protection against military grade radars.


  • Avionics Department, Naval Air Warfare Center Weapons Division Pt. Mugu. Electronic Warfare and Radar Systems Engineering Handbook. 2013.
  • United States General Accounting Office. Report to the Secretary of Defense: Electronic Warfare. 2001.
  • Electronic Warfare Technology -- Trends and Visions. Kenneth Helberg, Tony White, Kevin Geiger, Joseph Koesters, David Wilkes, and Lt Ron Merryman, Wright-Research & Development Center Avionics Lab (WRDC/AAWW).1990
  • Chaff,
  • EW 104: Electronic Warfare Against a New Generation of Threats by David L. Adamy. Artech House, Feb 1 2015
  • ALE-47 Airborne Countermeasures Dispenser System,

KEYWORDS: Expendable, active, Radio Frequency, helicopter, countermeasure, self-protection, electronic, radar, missile


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