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Helmet-Mounted Microbolometer Hostile Fire Sensor


TECHNOLOGY AREA(S): Electronics 

OBJECTIVE: Develop and deliver an uncooled microbolometer based small and medium arms hostile fire detection (HFD) sensor to be mounted on a helmet or small semi-autonomous or autonomous ground system. Appropriate algorithms to provide, at a minimum, angular direction to the origin of hostile fire events are required. 

DESCRIPTION: Especially when first engaged, it is often difficult for a soldier or autonomous system to quickly ascertain from where hostile fire has originated. This confusion prevents a quick and effective response to counter and eliminate the threat. This topic seeks to provide the soldier and autonomous system with a means to eliminate this confusion and allow well-informed and timely actions to be taken in response to hostile fire. Acoustic systems have been developed, but system performance is severely degraded in environments which are prone to multi-path acoustic reflections such as urban or forest environments [1]. Because the system is meant to be mounted on a helmet or small platform, it must be extremely light weight, low power, and possess an appropriate form factor: this is of primary importance in gaining user acceptance. Additionally, it should be compatible and not interfere with other commonly helmet-mounted systems such as night vision goggles. The final production system must also be cheap enough to justify equipping ground troops and small robotic platforms and run >12 hours minimum on batteries, ideally >24 hours. The sensor need not be imaging, but must provide at least angular direction to the origin of the hostile fire event. In order to provide the user with the best chance of quickly identifying and engaging the threat, the system should minimally be capable of identifying the angle to the threat with <30° resolution and <±15° error, but ideally <5° resolution with <±2.5° error. But, this must be balanced against SWAP-C; horizontal angular (azimuth) resolution is more important than vertical (zenith). The time lag between the shot and display to the user should be minimal, ideally <50 ms. Of course, probability of detection at tactically relevant ranges for small arms (500–600 m), such as common assault rifles and carbines, and medium arms (1–1.5 km), such as large rifles and machine guns, should be maximized (>90% minimum, ideally >95%) and false alarms close to zero. Other features, such weapon type identification, the ability to squelch alerts generated from friendly fire, and range to target, are desirable. The system must minimally operate at a brisk walking speed, >6.5 kph, and ideally at a sprint, = 25 kph. 

PHASE I: The proposer shall provide a complete helmet-mounted sensor design using only components which are COTS (commercial off-the-shelf) or those that could reasonably be designed and fabricated within the time and budget constraints. The sensor design need not be optimized for SWAP-C at this stage, but it must show extensibility to a usable and wearable system. A complete and thorough understanding of the algorithms necessary to make the sensor successful shall be demonstrated. Rigorous modeling shall be performed to estimate system performance, including at least probability of detection verses range, angular resolution and error, time to detect, and any other features. Sources of false alarms and potential mediation should be well thought-out and incorporated into the design. 

PHASE II: Using the results of Phase I, fabricate and deliver a prototype helmet-mounted HFD system. Prototype should meet requirements for TRL 4: component and/or breadboard validation in laboratory environment. All required sensors must be mounted to the helmet, but processing and power may be external at this stage so long as a detailed design path is provided to show that it can all be integrated onto the helmet (full integration is preferred). Probability of detection, angular resolution and error, and time to detect shall be measured through live-fire laboratory testing at close to moderate distance, at least 50–100 m. False alarm mitigation techniques should also be laboratory or field tested when possible. 

PHASE III: Transition applicable techniques and processes to a production environment with the support of an industry partner. Finalize a sensor design with appropriate SWAP-C and form factor based on human factors testing. Determine the best integration path as a capability upgrade to existing or future systems, including firmware and interfaces required to meet sensor interoperability protocols for integration into candidate systems as identified by the Army. 


1: G Tidhar, "Hostile fire detection using dual-band optics," SPIE Newsroom (2013).

2:  AMRDEC Public Affairs, "Serenity payload detects hostile fire," (2014).

3:  "Uncooled Multi-Spectral (UMiS) Hostile Fire Detection and Discrimination System for Airborne Platforms," (2015).

4:  E Madden, "Small Arms Fire Location for the Dismounted Marine," Navy SBIR 2015.3, (2015)

5:  L Zhang, F Pantuso, G Jin, A Mazurenko, M Erdtmann, S Radhakrishnan, J Salerno, "High-speed uncooled MWIR hostile fire indication sensor," Proc. SPIE, Vol 8012 (2011)

6:  S Nadav, G Brodetzki, M Danino, M Zahler, "Uncooled infrared sensor technology for hostile fire indication systems," Opt. Eng., Vol 50, No 6 (2011)

7:  M Pauli, W Seisler, J Price, A Williams, C Maraviglia, R Evans, S Moroz, M Ertem, E Heidhausen, D Burchick, "Infrared Detection and Geolocation of Gunfire and Ordnance Events from Ground and Air Platforms," (2004)

KEYWORDS: Hostile Fire, HFD, HFI, Uncooled, Bolometer, Helmet 


Dennis Waldron 

(703) 704-1488 

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