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High Acceleration and Hypervelocity Inertial Measurement Unit

Description:

TECHNOLOGY AREA(S): Weapons 

OBJECTIVE: Develop projectile compact inertial measurement units (IMUs) that are resilient to the high accelerations of gun launches and sufficiently small to fit in 155mm projectiles. 

DESCRIPTION: Gun-launching high-speed projectiles creates very significant acceleration loads on the projectile components. IMUs for a 155mm projectile also must be compact to meet size constraints and lightweight to minimize projectile weight. Additionally, a useful IMU must be sufficiently stable to have low drift rates when off-board sources of position, navigation, and timing are unavailable. The objective is to develop novel IMs for 155mm projectiles that survive the launch environments and are sufficiently small and lightweight to fit in a 155mm projectile. Given battery constraints of projectiles, the IMU must have low electrical drains. Similarly, hypervelocity projectiles operate in a thermally challenging environment, so, the IMU should contribute minimally to projectile internal heating. The IMU will need to meet operational requirements after gun launch accelerations of 50,000 g. The IMU should require no more than 0.5 cubic inches of volume, weigh less than X ounces, operate from -55°C to 140°C, and require no more than 1 Watt of power. Gyros: Dynamic range: ±36,000°/s and ±2,000°/s Bias, Turn on: <0.028°/s Bias, In-run: <0.1°/s Scale Factor: <0.035% Angle Random Walk: <0.1°/√hr Rate Random Walk: <1°/Hr/√hr Bandwidth: >70 Hz Misalignment: <3 mr G-sensitivity: <0.05°/s/g Accelerometers: Dynamic range: ±150 g Bias, Turn on: <10 mg Bias, In-run: 0.5 mg Scale Factor: 0.1% Velocity Random Walk: 0.04 m/s/√hr Bandwidth: >70 Hz 

PHASE I: Define and develop a concept for a lightweight, g-survivable projectile IMU. Perform modeling and simulation to provide initial assessment of concept performance. Phase I Option, assuming the assessment supports concept feasibility; describe the approach and capability to build prototype components in Phase II. 

PHASE II: Development of two prototype IMUs based on Phase I work for demonstration and validation. The prototypes should be delivered at the end of Phase II for testing by the government. IMUs will undergo canister gun launches to assess gun launch survivability. 

PHASE III: Manufacture of prototype IMUs based on Phase II and integration into three Government furnished projectiles for dynamic flight-testing. Successful testing will result in transition of the projectile IMUs into a program of record for acquisition. 

REFERENCES: 

1: Keith Sheard, Ian Scaysbrook, Derrick Cox. MEMS sensor and integrated navigation technology for precision guidance. Position, Location and Navigation Symposium, 2008 IEEE/ION.

2:  Soheil Habibi, Stuart J. Cooper, Jean-Michel Stauffer, and Bertrand Dutoit. Gun hard inertial measurement unit based on MEMS capacitive accelerometer and rate sensor. Position, Location and Navigation Symposium, 2008 IEEE/ION.

KEYWORDS: Projectile, Hypervelocity, Inertial Measurement Unit, IMU, High-g, Micromechanical Structures, Navigation, Production, Measurement Units, Sensor Systems, Electric Shock 

CONTACT(S): 

Francis Barnhart 

(703) 526-2681 

francis.barnhart@sco.mil 

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