SIGNAL PROCESSING MEANS FOR DETECTING AND SIGNAL PROCESSING MEANS FOR DETECTING AND DISCRIMINATING BETWEEN STRUCTURAL DISCRIMINATING BETWEEN STRUCTURAL
CONFIGURATIONS AND GEOLOGICAL GRADIENTS CONFIGURATIONS AND GEOLOGICAL GRADIENTS ENCOUNTERED BY KINETIC ENERGY PENETRATING ENCOUNTERED BY KINETIC ENERGY PENETRATING
PROJECTILESPROJECTILES
14 May 08
Expanding the Realm of Possibility
Program OverviewDevelop a Signal Processing Method to:
Detect and Discriminate betweenNatural & Structural Layers Encountered During Terra-Flight
Distinguish Gradients Encountered During Flight
Verify the Algorithm (method) Against Multiple Real World EventPatent the Algorithm
Expanding the Realm of Possibility
Program GoalsSet-up a Matlab Simulink Algorithm SimulatorVerify the Algorithm (method) against Multiple Real World Events (digital signals)Transfer Algorithm to ‘g’ Hardened DSP Controller Chip Develop Operator Interface for DSP ChipVerify Chip Operation with Real World Analog Signal Inputs
Expanding the Realm of Possibility
The Acceleration MeasurementThe Acceleration Measurement
Rigid Body (RB) Movements (Tape Measure) form basis of the Algorithm
Body encountering a resisting target with a force of opposite sense as velocity and proportional to V2
Rise time equal to crater depth (Nose Length)RB Waveform a non-structured trapezoid (= low frequency <100 Hz)
Expanding the Realm of Possibility
Time
Dec
eler
atio
n
ReboundSpringEnergy
Release
Lock-upProportional to VViscous/StokesDrag
Nose Entry
Penetration Phase
Characteristics of RB Acceleration Records
End of EventIgnored inAlgorithm
Expanding the Realm of Possibility
Superimposed On the Superimposed On the Measurement & Masking the Measurement & Masking the Rigid Body are:Rigid Body are:
KHz signal movements representing (i.e., measured by micrometers)
Vibrational modes of the penetrator structureMounting of the transducerInternal Component Freight Training
Some MHz signals representingSteel on Steel contactKinematic Mass Property Changes 0.015 0.02 0.025 0.03 0.035 0.04 0.045 0.05 0.055
-2
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-1
-0.5
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1
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x 104
time(seconds)
g's
Expanding the Realm of Possibility
UnUn--Masking the Rigid Body MovementMasking the Rigid Body Movement
It is known (One Way) that an integral will detect layers
But slope detection merely returns the signal
What Venue supports detection of targets masked by High Frequency Content signals?
AnswerRadar TargetsLFM Acquisition (Purposely Masks LF Target) and detected by Pulse Compression (An Integration)
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x 104
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Expanding the Realm of Possibility
Pulse CompressionPulse Compression ItIt’’s Analog to Decelerations Analog to Deceleration
Energy to a target has been purposely modulated with multiple frequencies. Multiple Freq Sources in Projectile.The target is hit with the energy and returns a high frequency content (HFC) signal. Penetrator strikes target & returns HFC SignalEach ‘f’ contains target information, both cases – Goal = ExtractThe return pulse is compressed by slowing down the high frequencies and speeding up the low frequencies using analog devices or
A matched filter used but this is an autocorrelationDue to the high frequency of the return radar signal analog pulse compression is easier then digitizing and running an autocorrelation.Due to the relatively low frequency of a penetration event KHz versus GHz, digitization and autocorrelation is more appropriate.Results are the same:
Target resolved in range (ringing removed and info stored in low freq range resolved pulse)
Expanding the Realm of Possibility
Pulse Compression = Auto CorrelationPulse Compression = Auto Correlation
Pseudo
Expanding the Realm of Possibility
0.75ft (5ksi) + 13ft air + 0.75ft (5ksi) + 13ft air + 0.75ft (5ksi) + 13ft air + 4 ft (10ksi) + 1.7ft air + 4ft (10ksi)
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-0.5
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1x 10
4
Counts = Time*200000
g's
Multi-Layer Target
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3x 107
Counts = Time*25000
g2
Autocorrelation
+ Nice Range Resolution
Expanding the Realm of Possibility
Where is the Uniqueness?Where is the Uniqueness?In a sphere, cylinder, plane, concrete?In a radar system each target is identified by a unique number (its RCS)In a penetrating system each target is identified by a unique unit less value called peak ‘g’This identifier is independent of striking or draining velocity and only dependent on geometry and target resistanceTherefore penetrator targets (for the same penetrator geometry) that are not the same are different
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Peak 'g' Convergence
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Penetration Depth
Peak 'g' Convergence
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Expanding the Realm of Possibility
2
)42.32( 1
1gtVstNL −=
2)(2.32 2
2tgNLDF =−2
]2[2.32 21 ttgVs −=
G’s
1t 2t
Vs=Striking Velocity NL=Nose Length
DF=Final Depth of Penetration
Expanding the Realm of Possibility
If Correct Data Should ConvergeIf Correct Data Should Converge to Single Valueto Single Value
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y ft/s
ec
Depth of Penetration ft
Peak 'g' Convergence
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Velocity (feet/ sec)
Dep
th o
f Pen
etra
tion
(fee
t)
GENPEN 9.25 CRH 350#L/D = 10 Antelope Lake, Nevada
GENPENFit
Velocity Stepped thru Natural Cemented Sand Target
Expanding the Realm of Possibility
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Peak 'g' Convergence
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Velocity (ft/ sec)
Pene
trat
ion
Dep
th (i
nche
s)
3CRH, 1Kg, L/D=10,Limestone
Concrete DataFit
Velocity Stepped thru Limestone Target
Expanding the Realm of Possibility
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g's
Velo
city
Penetration Depth
Peak 'g' Convergence
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Velocity (ft/ sec)
Pene
trat
ion
Dep
th (i
nche
s)
3CRH, 13Kg, L/D=7, 3.5Ksi Concrete
Concrete DataFit
Velocity Stepped thru Concrete Target
Expanding the Realm of Possibility
Expanding the Realm of Possibility
7x10^6
Expanding the Realm of Possibility
Expanding the Realm of Possibility
Expanding the Realm of Possibility
Program AccomplishmentsA Robust Matlab Simulink Algorithm Simulator was set-upThe Algorithm was Tested against Multiple Real World Events (digital signals)The Algorithm was transferred to a ‘g’ Hardened Freescale DSP Controller Chip with Operator InterfaceChip Operation was verified with Real World Analog Signal Inputs to the ChipThe Algorithm is Patent Pending