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Gunner Primary Sight (GPS) Shock Isolator




OBJECTIVE: Develop a material and structural solution designed to be integrated onto the M1A2 Abrams tank and isolate the Abrams Gunner Primary Sight (GPS) system from the turret. The isolator shall reduce MIL-STD-810G ballistic shock inputs in all 3 axes, to levels which allow various optical vision systems to continue functioning. This problem can be solved by leveraging structural and material solutions to dampen the shock input to the sights system by the turret. It’s critical that the proposed isolator shall take into account secondary effects on that of boresight alignment/retention, and stabilization both prior to and after a ballistic shock. The successful isolator design concept shall not introduce resonances that would amplify input shock and vibration levels. It should be noted that while the isolator may grow the GPS in the vertical direction, there should be no structural modifications to the current turret, with the present GPS mounting bolt pattern being utilized. 


DESCRIPTION: As currently designed the Abrams GPS is hard mounted to the turret so as to minimize spatial movement and maintain the GPS’ angular relationship with the turret and other hardware mounted within the turret. This mounting strategy is intended to provide improved capability as it relates to locating and hitting targets. However, this strategy also allows shock impulses to be transmitted to hardware within the GPS with little attenuation. As a result of advancements in technology and materials it’s the intent of the Abrams office to determine an alternative means of mounting the GPS so as to maintain current capabilities while improving the survivability of the sight system (GPS) when subjected to a ballistic shock event. In order to reduce the number of modifications to other turret systems/hardware as a result of integrating the isolator, there is a maximum height constraint of 4 inches (T), with a design objective for the isolator to add 0 inches of height (O) to the Abrams turret. The described Threshold and Objective height constraints are measured from the current mounting location for the GPS on the turret roof. The Threshold defined maximum height of 4 inches allocated to the shock isolator will not have an effect on transportability given the height of other components mounted to the Abrams turret. Currently the secondary sight on the tank, CITV, has an isolator which provides this ballistic protection capability to the Commanders sight. While technology challenging, this integrated design has proven that fielded solutions exist. The challenge moving forward is the two sights are structurally different and therefore a common solution is not possible. 


PHASE I: Demonstrate feasibility of an isolator concept by means of modeling and simulation tools. For this analysis, the Government will provide a GPS model with appropriate mass and material properties. In addition to a reduction in ballistic shock, any analysis should also include the effect the isolator would have on the operation of the GPS due to vibration in the tanks operational environment. Success in Phase I would be to show a reduction in shock loading to the GPS as a result of the Abrams turret (to include shock isolator) being subjected to the Government defined MIL-STD-810G ballistic shock (an SRS plot can be provided if needed). Shock reduction to the GPS as a result of the isolator should be less than or equal to the shock profile defined as 200G 0.5ms half sine (an SRS plot can be provided if needed). An assessment for how easily the proposed isolator can be manufactured shall be delivered in this phase. 


PHASE II: Design and build the prototype isolator for integration onto an Abrams M1A2 SEPv2 or M1A2 SEP V3. This should include a Bill of Materials that identifies if the parts are “off the shelf “custom made and so on. The delivered prototype must be suitable for testing at an Army facility by technical personnel. As noted in Phase I, success is achieved when the Abrams turret (with isolator and GPS installed) is subjected to a live fire test event and the isolator is able to reduce the shock input on the GPS to a value less than or equal to 200G 0.5ms sine wave. If required, clear installation and operational manuals shall be submitted but no specific military format. During this phase, the Army expects to work closely to clarify mission integration requirements appropriate for the initial prototype maturity. 


PHASE III: Final solution is an isolator designed for the Abrams GPS which maintains current capabilities of the sight system while also improving survivability of the sight systems after a ballistic shock. The Army can integrate the technology solution developed under this SBIR into the family of Abrams vehicles, Army and Marines, given the commonality of the GPS structure to all variants. 



1: MIL-STD-810G, Department of Defense Test Method Standard for Environmental Engineering Considerations and Laboratory Tests" (PDF). United States Department of Defense. 31 Oct 2008.

2:  Walton, W. Scott, "Ballistic Shock Simulation Techniques for Testing Armored Vehicle Components," Proceedings of the 64th, Shock and Vibration Symposium, Volume I, October 1993, pp. 237-246. Shock & Vibration Information Analysis Center (SAVIAC), Three Chopt Rd. (Suite 110), Richmond, VA 23229.

3:  Walton, W. Scott and Joseph Bucci, "The Rationale for Shock Specification and Shock Testing of Armored Ground Combat Vehicles," Proceedings of the 65th Shock and Vibration Symposium, Volume I, October 1994, pp. 285-293. Shock & Vibration Information Analysis Center (SAVIAC), Three Chopt Rd. (Suite 110), Richmond, VA 23229.

4:  Egbert, Herbert W. "The History and Rationale of MIL-STD-810," February 2005 ; Institute of Environmental Sciences and Technology, Arlington Place One, 2340 S. Arlington Heights Road, Suite 100, Arlington Heights, IL 60005-4516.

5:  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.



KEYWORDS: Abrams, Gunner Primary Sight, GPS, Shock, Ballistic, Isolation, Isolator, Sights, Boresight, Survivability 


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