approved for public release presentation to 39 th annual gun/ammo & missiles/rockets conference...
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Approved for Public Release
Presentation to 39th AnnualGun/Ammo & Missiles/Rockets Conference
Deconstruction of Fuze Well Guidance Requirements
April 14, 2004Chris Geswender
cegeswender@raytheon.com Andy Hinsdale
Andrew_J_Hinsdale@raytheon.com
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Synthesis of Course Correcting Fuze Design
Determine best Solution Spaceto developing a fuze well based
guidance package to providefirst shot accuracy < 50 meters
Corrects major errors including• Inherent Gun laying errors• Muzzle Velocity Variation• MET errors
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Derived Requirements• Increase effectiveness and efficiency of cannon artillery
• CEP<50 meters
• Reduce logistics• Increase OPTEMPO
• Exploit large existing projectile war stocks• Fuze well implementation
• Reversionary mode (fuze only)
• Corrector must still be a fuze• Easy to install, program, and be robust to field handling
• Volume for fuze functions
• Must have a reversionary mode
• Cost << $5000
Unguided1DOF
2DOF
3DOF-7DOF
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ACCURACY Definitions
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Gun Target Line
(GTR)
Target Center
DEFLECTION Bias Error
Mean Point of Impact (MPI)
RANGE Bias Error
Mean Point of Impact
(MPI)
DEFLECTION
RANGE
Precision Error
(Range)
Precision Error
(Deflection)
Mean Point of Impact
(MPI)
(Dispersion)
(Dispersion)
Range errors dominated by• Muzzle velocity variation• MET
Deflection errors dominated by• Gun Laying errors• MET
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Alternate Concepts Number of known concepts1DOF- Downrange
1DOF- Cross range
2DOF-DecoupledRoll stabilizedRoll rate Stabilized
2DOF-Body fixedRoll Rate/Aerobrake (1+)Flow disruptionHF Fixed canardHF trailing canard / solenoid
Wide Potential Solution Space
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Some Examples
1DOFRange Correctors
2DOFRange/Deflection Correctors
NSWC GIF
STAR SPACIDODMS
MIT Concepts
ANSR
1DOFDeflection Corrector
CMATD
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Theory of Operation - 1DOF-R
Projectile initializedand fired
“over” target
Projectile acquires“truth” of its positionand estimates impact Projectile determines
best point for high dragtrajectory to impact
Projectile deploys
aerobrakes
Minor modificationto firing tables
required(range and deflection)
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Theory of Operation - 2DOF
Requires no modificationsto firing tables
Projectile initializedand fired at target
Projectile acquires“truth” of its positionand estimates impact
Projectile determines best point for start guidance
Projectile deploys
aero surfaces
Projectile continuously
corrects impact
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x 2 VmFCCF
mV
Out of plane force
Mass
Velocity
Rotation
Aerodynamic Force Vector
Spin Stabilizing Rotation
Body Rotational Moment
Aerodynamic Force Vector
No Rotation
Body Rotational Moment
Projectile (12)
Fc ( coriolis acceleration ) (15)
V ( linear motion ) (14)
( rotation ) (13)
Theory of Operation - 2DOF Control
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Potential “truth” sources for Guidance
• Ballistic
• Inertial
• Data Link Update (Command)
• GPS
• Ground Beacon Array
• Terminal Seeker • (seeker range, packaging, costs issues)
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Summary of “Truth” Sources for Guidance
Ba
llis
tic
Ine
rtia
l
Gro
un
d
Be
ac
on
s
GP
S /
IM
U
Co
mm
an
d (
PT
S)
Beacon Error Sources
Maximum range LOS altitudeBeacon siting error
Beacon NORTHing error
Beacon signal errors - range noise
Beacon signal errors - angle noisePlatform error corrections
Corrects Gun- Laying angle errorsCorrects gun NORTHing error
Corrects Muzzle exit velocity errorsOperational Considerations
All-weather
Sensitivity - Countermeasures
Compatible to moving targets
Radiating Shooter
GPS or GPS/INS Appear to be Most Appropriate Truth Sources
See
ker
Technical and Cost Considerations
Integration ChallengesUnit Cost
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Electronics
Stowed AeroSurfaces
Actuators
Representative 2DOF Fuze / Guidance Kit
Battery
FS&A Booster
Primer
Fuze
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Various Studies Have ShownConcept Feasibility
CL~.02
CL~.015
Reference –Aerodynamic Fuze Characteristics A.M. BudgeJune 1998 MIT
•Various CCF/GIF Studies have indicated sufficient Maneuverability with Low aerodynamic effect lifts. •However, these studies widely vary as to real life implementation fidelity (winds aloft / guidance law interaction, guidance start times, actuation constraints)•Without considering realistic winds aloft many control concepts will appear satisfactory•But due to physics of the spinning projectile there is a practical limit to useful CL authority
52224.0184222.05119941.0965133250.5877469690.25
67%33%10%Wind
Canard
6.0
4.0
2.0
1.0
0.5
0.25
100%67%33%10%
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GIF/CCF Requirements Deconstruction
Can Correct Trajectory Dispersion
1D-R 1D-D 1D+ 2D 3D 4D 5D 6D 7D
1D+ 2D 3D
1D+ 2D 3D 4D 5D 6D 7D
NATO STANAG Compatible Concepts
1D-R 1D-D 1D+ 2D 3D 4D 5D 6D 7D
Can Correct CEP <50m
Can Cost < $5K
1D+ 2D 3D
Fuze Well Compatible
1D+ 2D
A/J capable with no special handling HIGH GPS AJ capable
3D
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Summary
• Depending on desired Operational Flexibility and Cost Sensitivity, there are a number of potential solutions.
• Spiral development from the 1DOF (presently easily implementable) to the final desired operational product (2DOF or 3DOF) is an option
• GPS or GPS/INS are the most appropriate “truth” sources
• Joint service kit requires 2DOF or 3DOF kit at minimum
• To avoid developing new ballistic tables, nose weight/shape should conform to NATO STANAG OML
• Implementation of actuation and power source are the technical challenges
• Packaging of a gun hardened unit is also a challenge
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