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Innovative Technologies for Precision Timingof Onboard Munition Navigation Systems

Description:

TECHNOLOGY AREA(S): Weapons

OBJECTIVE: Develop a technology for precision time in the onboard navigation systems of precision guided munitions (PGM) for purposes of navigation and to assist with post launch acquisition and tracking of Global Positioning System (GPS) or alternate navigation sources (ALT-NAV).

DESCRIPTION: The U.S. Army has a need for precision time in the onboard navigation systems of precision guided munitions (PGM), such as Excalibur or Precision Guidance Kit, for purposes of navigation and to assist with post launch acquisition and tracking of Global Positioning System (GPS) or alternate navigation sources (ALT-NAV).Current PGM systems can experience relatively large errors in timekeeping (seconds) during the gun launch, due to the shock of the 12,000+g loads experienced in the gun barrel.The resultant time uncertainty increases the risk to acquiring GPS or ALT-NAV sources in challenged environments, makes the PGM entirely reliant on successful acquisition of a trusted time source (eg. GPS) to reset the clock post-gun-launch.Currently available alternatives are either less survivable in the gun environment, do not meet size (less than 1 cubic cm), weight (less than 1 ounce), and power constraints (less than 1 watt) (SWaP), or would require too much time to temperature stabilize pre-launch. Operating temperatures range from -40 degrees to +160 degrees Fahrenheit. Technologies that have the potential to be significantly more preciseand less susceptible to time shifts during gun launch, enabling the keeping of accurate time (less than 10 ms) through the gun environment and enabling improved acquisition of GPS and ALT-NAV sources without any adverse SWaP impacts.Potential beneficial applications extend beyond the PGM environment, since these devices could prove to have positive SWaP implications without compromising performance. The end result of this effort would be a technology that is fully performance characterized and proven in the extreme gun environments, and ready for integration in munitions such as Excalibur, Precision Guidance Kit - Anti-Jam (PGK-AJ) and Hypervelocity Projectile (HVP).

PHASE I: Phase I will consist of an engineering study that will result in laboratory bench top prototypes demonstrating the performance requirements in a laboratory setting. The main focus of the testing will be to demonstrate the timing capability, with an engineering assessment of performance in the actual weapon firing environment. A final report will document all results and analyses. THe Phase I Option, if exercised will develop the system performance specification documenting system requirements and test methods.

PHASE II: Phase II will further mature the technology to meet all requirements in the system requirements specification, with a final demonstration in a relevant environment such as gun launch. Actual gun launch tests will be performed at a government facility with contractor support.

PHASE III: Phase III will integrate and qualify the technology in a full-up munition in preparation for transition to production.

KEYWORDS: precision timing, precision munitions, guidance and navigation, PNT, GPS, atomic clock, oscillator

References:

No Warmup Crystal Oscillator, Naval Research Laboratory (no author), December 1981, (https://apps.dtic.mil/dtic/tr/fulltext/u2/a494478.pdf); TCMO(tm): A Versatile MEMS Oscillator Timing Platform, K. J. Schoepf et al, November 2009 (https://apps.dtic.mil/dtic/tr/fulltext/u2/a519709.pdf); Comparison of Crystal Oscillator and Si-MEMS, Seiko Epson Corp, no date(https://www5.epsondevice.com/en/information/technical_info/pdf/wp_e20140911_osc.pdf); Electronic Components for High-g Hardened Packaging, Morris S. Berman, January 2006 (https://apps.dtic.mil/dtic/tr/fulltext/u2/a443252.pdf); Development of an Air Gun Simulation Model Using LS-DYNA, Mostafiz Chowdhrey & Ala Tabiei, July 2003 (https://apps.dtic.mil/dtic/tr/fulltext/u2/a417052.pdf); NOTE: The reference to any particular company or product is for information only and not an endorsement of that company or their technology.

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