SITIS Archives - Topic Details
Program:  SBIR
Topic Num:  AF071-146 (AirForce)
Title:  Deeply Buried Hardened Target Fuze
Research & Technical Areas:  Weapons

 The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), which controls the export and import of defense-related material and services. Offerors must disclose any proposed use of foreign nationals, their country of origin, and what tasks each would accomplish in the statement of work in accordance with section 3.5.b.(7) of the solicitation.
  Objective:  Develop a non-inertial sensor and associated signal analysis algorithms for reliably sensing the presence and characterizing voids during penetration of a hardened target.
  Description:  “Smart” fuzes for penetrating weapons currently utilize various algorithms to detect the presence of layers and voids (i.e., empty spaces, such as floors) in a hardened target. The analysis is performed on the output from a set of accelerometers, but the dynamic penetration environment introduces a large amount of mechanical noise that makes detection difficult. Additionally, the dynamics of the penetrator itself is highly variable even under nominally identical impact conditions. This uncertainty can be mitigated through the use of additional sensing means. AFRL/MNMF, in conjunction with AAC, seeks to develop novel approaches and the underlying technologies to augment the detection of voids and layers by inertial sensors. The output of non-inertial sensors is expected to improve the recognition of target features from a sensor fusion standpoint, potentially providing an orthogonal (statistically independent) information stream. With further refinement, using complementary information may enable “brilliant” fuzes that can recognize particular target features (such as a surrounding media) in addition to events (such as impact with a hardened concrete layer). Eligible approaches can utilize any non-inertial means to probe the environment, such as electromagnetic radiation. The approach can be active, passive, or a combination of several types. However, the approach must fit within the physical constraints of a fuze (a cylinder approx. 3 in diameter and 6 in long) without modifying the existing warhead casing or other internal components of the warhead. The penetration of a target involves rapid movement through disintegrating media. The resulting debris field is a potential source of interference for the detector(s). Additionally, the harsh environment of penetration gives rise to spurious broadband noise that might degrade the signal-to-noise ratio of particular approaches. All features of the sensor must be able to survive and function under extreme mechanical loading, with instantaneous accelerations exceeding 100kg (i.e., 100,000 times the acceleration of gravity) possible over a several millisecond time span. The recognition of target features must also be nearly instantaneous, with a decision rate greater than 5 kHz; this implies a much faster sensor sampling rate. For example, a weapon traveling at 500 fps must be able to recognize a layer or void in much less than 1 ms to obtain one foot resolution while preventing aliasing and improving detection confidence. The expected radial detection range from the axis of the weapon must be greater than 5 ft; detection of near-field (<6 in) features is desirable. The sensor must be able to detect at least three voids in a 15 ft. target. Use of the candidate method(s) for cavitation measurements in penetration experiments will also be explored.

  PHASE I: Perform an analysis of alternatives (AOA) trade study to identify and justify the best concept(s) for non-inertial void detection and layer counting during hard target penetration. Provide a “proof-of-concept” benchtop demonstration of a brassboard non-inertial sensor.
  
  PHASE II: Demonstrate functionality of a hardened prototype of the proposed sensor concept during impact loading of ~30kg for 1 ms. Perform field testing to demonstrate robustness and accuracy of the concept.

  DUAL USE COMMERCIALIZATION: Military application: A successful effort will have military application in future hard target smart fuzes that will be used within hard target weapons such as the BLU-109. Commercial application: Potential commercial uses include automotive testing (crash tests), search and rescue, and vehicle design for dynamic control.

  References:  1. Jane’s Defense Weekly 2. Munitions Directorate Homepage <http://www.mn.afrl.af.mil/> 3. Military Handbook of Fuzes, MIL-HDBK-757(AR), 15 April 1994. (Public Releasable via USA Information Systems, Inc; www.usainfo.com, 757-491-7525) 4. CAF-90-I/II-A Hard Target Smart Fuze ORD

Keywords:  Smart fuze, fuzing, void sensing, void detection, layer counting, hard target, penetration environment, programmable fuze, sensor, non-inertial, accelerometers.

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