intelligent fuzing fuzing for penetrating munitions ... fuzing fuzing for penetrating munitions:...

Intelligent Intelligent fuzingfuzing for penetrating munitions: for penetrating munitions: experiments and analysis of representative experiments and analysis of representative

configurationsconfigurations

5353ndnd Annual Annual FuzeFuze ConferenceConference

Lake Buena Vista, FL, USA, 19Lake Buena Vista, FL, USA, 19--21 May 200921 May 2009

Jean-Marc SibeaudCentre d’Etudes de Gramat BP 80200

F-46500 GRAMAT

Centre d ’Études de Gramat 53rd annual Fuze Conférence 19-21 May 2009 Slide N°2

MINISTÈRE DE LA DÉFENSE

Area of Area of activityactivity

CEG is Technical Center of the French MoD procurement Agency (DGA)

Expert center for Terminal effectiveness of Conventional Air-to-Ground weapons and missiles

Gives support to program managers for weapons or components development (SCALP/EG missile, AASM PGM, MdCN Navy cruise missile, FBM 21 fuze for air delivered munitions)

Provide Armée de l’air and Aéronavale (French Air Force and Navy Air Force) with means for determining effectiveness of strikes and perform mission planning

Anticipate on threat evolution



Next generation Next generation fuzingfuzing will make use of will make use of embedded intelligenceembedded intelligence

Hardened targets (Hard target defeat) and soft targets

Objective: Improve warhead lethality while minimizing collateral damage

Capability to control weapon’s depth of burst and eventually full trajectory



Soil

Concrete

DHE

V

Desired depth of weapon

detonation

DN

Hard and soft targets defeat: optimal Hard and soft targets defeat: optimal fuzefuze delay delay depends on target and weapon parametersdepends on target and weapon parameters

Subsoil

Void

maximum lethality if point of detonation located at the right place

HE loading CoG



ValidatedValidated analyticalanalytical and and computationalcomputational toolstools existexist to help to help predictpredict the the fuzefuze delaydelay for for a a givengiven missionmission

CEG and the French targetting Center operate the CalPen3D analytical program that computes the curvilinear trajectory of the weapon within the target

The fuze delay is therefore accessible to the mission planner

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Case#1-configuration#1: triaxial nose and tail sensing

Case#2-configuration#1: triaxial nose and tail sensing

SoilConcrete

Concrete



Hard target defeat: unexpected situations using a Hard target defeat: unexpected situations using a constant constant fuzefuze delaydelay

Reduced lethality

Thicker Concrete slab than expected



Smart Smart fuzingfuzing

The munition analyses its environnement and triggers the HE charge when conditions are met

Void sensing

Layer counting

Trajectory calculation

In this latter option, the warfighter specifies the point of detonation instead of a fuze delay

High-G sensors, rugged electronics and complex algorithms must be developped and integrated



An illustration of the An illustration of the possibilitiespossibilities and challenges: and challenges: perforatingperforating of of spacedspaced concreteconcrete plates plates withwith a model a model scalescale projectileprojectile

T = 0

T = 10 ms

Prior to testingPost testing

Finite element simulation295 m/s

AOI = 0°



PresentationPresentation of the EMHAC of the EMHAC HighHigh--G recorder and G recorder and ExperimentalExperimental resultresult

CAPTEUR

Triaxial T2M-Junghans Shock datta recorder

Range of data acquisition ± 20 kGs (Channel X1) ; ± 60 kGs (channels X2, Y, Z)

Storage duration : unlimited (FLASH memory)

Sensors : Endevco Accelerometers

Sampling rate : up to 500kHz (4-channel) or 1MHz (2-channels)

Memory size : 256 M samples

Reusable

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EMAHC recovered data



Double Double integrationintegration of signalof signal

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2µs sampling period

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229 m/s

203 m/s

251 m/s

Nose position

295 m/s

10.8 ms

2500 mm

… provides continuous velocity and displacement time histories

prior knowledge of initial conditions (velocity) is required

Smart fuze development would require knowledge of initial conditions (velocity)

Must be transferred from weapon guidance system



Influence of Influence of samplingsampling rate and rate and filteringfiltering on on velocityvelocity

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2 µs sampling period2 µs sampling period - filtered 0.2 ms2 µs sampling period - filtered 0.6 ms0.01 ms sampling period0.1 ms sampling period

Consistent velocity prediction requires minimum sampling rate (at least 100 kHz or one sample every 0.01 ms)Filtering of acceleration signal has marginal effect on velocity determination



Influence of Influence of samplingsampling rate and rate and filteringfiltering on on locationlocation

Prediction of displacement highly affected by sampling rate

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2 µs sampling period filtered 0.2 ms

2 µs sampling period filtred 0.6 ms

0.01 ms sampling period

0.1 ms sampling period

~ 500 mm error in weapon location (at small scale) using lowest rate sampling



NumericalNumerical simulation simulation capabilitiescapabilities in in orderorder to to betterbetter understandunderstand processprocess

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Experiment 8049 - SDR Filtered 0.2 ms

Calculation - SDR filtered 0.2 ms

FE calculation result match reasonnably well data (both filtered similarly)

FE prediction need to be improved in order to reduce frequency mismatch (eigen modes of model must be monitored)



AnalyticalAnalytical modelingmodeling ((CalPenCalPen curvilinearcurvilinear calculationcalculation of of projectile projectile trajectorytrajectory withinwithin the the targettarget))

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from acceleration filtered - 0.6 msfrom acceleration filtered - 0.2 msFrom original acceleration samplingPléiades

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Experiment 8049 - SDR Filtered 0.2 ms

Calculation - SDR filtered 0.2 ms

Pléiades analytical calc.



Next step : analysis of a plane trajectory using Next step : analysis of a plane trajectory using experiments at scale 2/3 (see experiments at scale 2/3 (see FuzeFuze 52 paper)52 paper)

Assumption : plane trajectory

1 sensor – 1 axis

1 sensor 2 axis (longitudinal (x) and transverse (y) of projectile)

2 sensors 2-axis per sensor

t = 0 ms V = 349 m/s

t = 15 ms V = 229 m/s

Pléiades T5-D

t = 9.4 ms V = 230 m/s

Exp. T5-D



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T5T5--D configuration D configuration -- 2 sensors 2 sensors ––22--axisaxis

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CalPen Simulation

Integrated from 1 point 2-axissensor

From projectile x-axis only sensor

Single axis sensing performs well provided that initial direction of munition is given

If this data is not available integration of x and y strapdown signals provide the expected trajectory and depth. Error appears important because of ricochet of munition on vertical wall cannot be interpreted by a single point sensor



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CalPen

2-sensor 2-axis

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2-sensors 2-axis

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T5T5--D configuration D configuration -- 1 sensor 1 sensor –– 1 and 21 and 2--axisaxis

Accurate if trajectory is plane

Angle between projectile and inertial coordinate axis can be calculated and therefore inertial accelerations from which velocity and position are derived

Deviation due to out plane excursion



General case : curvilinear trajectoryGeneral case : curvilinear trajectory

To be developed and hopefuly presented at the 54th annual Fuze Conference



ConclusionConclusion

Shock data recorder provides invaluable information for penetrator trajectory analysis and identification of challenges posed by smart fuzing for Hard target Penetration applications

Three channel Shock data recorder currently investigated

Use of multiple miniature G-hardened sensors may allow inertial measurement to be done and therefore a precise determination of the detonation point in the target core

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