Upload
truongtruc
View
232
Download
0
Embed Size (px)
Citation preview
NAVAL SURFACE WARFARE CENTER
DAHLGREN DIVISION
16 April 2010
Mike SlocumE3 Assessment and Evaluation Branch
540-653-2212
Approving Authority: NSWCDD
Command
US Navy RFID HERO Risk Mitigation
&
Shipboard Demonstration
DISTRIBUTION STATEMENT “A"
Approved for Public release; Distribution is Unlimited
NSWCDD Electromagnetic Effects Division (Q50)
ELECTROMAGNETIC & SENSOR SYSTEMS DEPARTMENT
Agenda
HERO & E3 Stakeholders
HERO Governance
– Philosophy : Specification : Recommendations
– Certification Process
Electromagnetic Risk Assessment Tool (EMRAT)
Shipboard Demonstration of pRFID
ELECTROMAGNETIC & SENSOR SYSTEMS DEPARTMENT
RFID E3 Stakeholders
EMAC serves as the Lead E3 Engineering Agent for both
NAVSEA and NOSSA for AIT (RFID) and Wireless.
NOSSAOrdnance Safety
NSWCDDTechnical Development
EMACHERO & E3
OPNAVNAVSEA
ELECTROMAGNETIC & SENSOR SYSTEMS DEPARTMENT
HERO Philosophy
Conventional HERO evaluations are based on RF propagation in free space
– Safe operations are achieved by separation of transmitter and ordnance (direct line of sight)
In many/most cases RFID systems will be used in enclosed electrically reflective spaces– Free space attenuation is not always dominant
– RF reflections and multiple transmitters in enclosed spaces result in an additive effect Such spaces become low-power microwave ovens Resultant electric fields are dependent on construction
materials and volume
– A derivative of Reverberation Chamber Calibration methodology developed to characterize such spaces(1)(2)
(1) DoD E3 Symposium, San Diego, CA April 2008
(2) IEEE EMC Symposium, Detroit, MI August 2008
ELECTROMAGNETIC & SENSOR SYSTEMS DEPARTMENT
HERO E-Field Limits
Governing Specification
– NAVSEA OP 3565 Vol. 2
0.1
1
10
100
1000
0.01 0.1 1 10 100 1000 10000 100000
Frequency (MHz)
V/m
E=0.5 V/m
E=0.00625 fE=1/f
902 MHz = 5.6 V/m
928 MHz = 5.8 V/m
Figure 2-2, Maximum Allowable Environment for HERO Unsafe Ordnance
ELECTROMAGNETIC & SENSOR SYSTEMS DEPARTMENT
HERO E-Field Limits (cont.)
Governing Specification
– NAVSEA OP 3565 Vol. 2
HERO CLASSIFICATION MINIMUM SEPARATION
DISTANCE (FT.) SAFE SUSCEPTIBLE UNSAFE OR UNRELIABLE
> 10 General HERO
Requirements
Use Calculated Distance
per OP 3565
Use Calculated Distance
per OP 3565
5 0.5 < EIRP < 5 watts
All Frequencies
EIRP < 0.5 watts
Frequencies > 100 MHz
0.025 < EIRP < 0.1 watts
200 MHz < Freq < 1 GHz
1 0.1 < EIRP < 0.5 watts
All Frequencies
0.025 < EIRP < 0.1 watts
Frequencies > 200 MHz
0.025 < EIRP < 0.1 watts
Frequencies > 1 GHz
0 EIRP < 0.1 watts All
Frequencies
EIRP < 0.025 watts All
Frequencies
EIRP < 0.025 watts
Frequencies > 100 MHz
Table 3-1, Minimum Safe Separation Distance Exceptions
ELECTROMAGNETIC & SENSOR SYSTEMS DEPARTMENT
HERO E-Field Limits (cont.)
EMAC Recommendation to NOSSA
– Guidance to address interior spaces
0.0
50.0
100.0
150.0
200.0
250.0
300.0
350.0
400.0
450.0
0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000
Frequency (MHz)
uW
/Ft2
Ships
Shore
590367.0 fPA
90367.0 fPA
915 MHz = 92.58uW /Ft2
915 MHz = 42.58uW /Ft2
ELECTROMAGNETIC & SENSOR SYSTEMS DEPARTMENT
AIT HERO Certification Process
NSWCDD: Conducts technical evaluation of equipment to establish engineering constraints.
– SSD & TRP
Program Office/Installation Activity: Develops CONOPS which adheres to engineering constraints.
Program Office/Installation Activity : Submits usage plan (CONOPS) with associated engineering evaluation to NOSSA for certification.
– NOSSA will consult with DD as required
Joint services and industry not under Navy cognizance
– NSWCDD will provide engineering constraints in report Letter will state HERO compliance requires adherence with findings
to adequately mitigate risk of HERO
NOSSA will provide certification for government activities only.
ELECTROMAGNETIC & SENSOR SYSTEMS DEPARTMENT
Electromagnetic Risk
Assessment Tool (EMRAT)
Chamber
Measurements
Shipboard
Measurements
Statistical EM
Theory
EM Modeling
& Simulation
EM Below Deck
Risk Assessment
Tool
E-Field
Prediction(1)
(4)
(3)
(2)
Below-Decks Electromagnetic Environment
ELECTROMAGNETIC & SENSOR SYSTEMS DEPARTMENT
HERO Risk Mitigation Process
Space
Content
4)
Electromagnetic
Ray Casting
Simulation
3)
Statistical
EM
Space
Characteristics
Input
E < ELIMIT
2)
Load Q
Database
E < ELIMIT
1)
In-Situ
Measurement
Upper Bound
E-Field
N
N
Y
Upper Bound
E-Field
Upper Bound
E-Field
Y
“Tunable Accuracy”
ELECTROMAGNETIC & SENSOR SYSTEMS DEPARTMENT
Reverberant Spaces
Multi-path propagation
Statistical electromagnetic environment
Random walk properties
Electrically large, reflective spaces
ELECTROMAGNETIC & SENSOR SYSTEMS DEPARTMENT
Multi-Path vs. Direct PathIn
sert
ion
Lo
ss (
dB
)
0
-10
-20
-30
-40
-50
Tx – Rx Distance RC
Direct Path
Multi-Path
Critical Distance: c
volDDR rxtxC
2
1
ELECTROMAGNETIC & SENSOR SYSTEMS DEPARTMENT
Multi-Path Critical Distance
Example
Vol ~ 200 m3
~ 30 ns (Q ~ 500 at 2.4 GHz)
Antenna directivity ~ 1.6 (half-wave dipole)
Critical Distance for antenna separation RC ~ 3 m
R > RC Multi-Path is Dominant even if antennas are bore-sighted !
ELECTROMAGNETIC & SENSOR SYSTEMS DEPARTMENT
Reverberant Space Equations
Gain G
Quality Factor Q
Receive Power Probability
Binomial Trials for Random Walk
Q
Volf
c
P
PGain rxtx
input
locantrec 1
16
13
3
2
..
)(3 MHzf
AreaSurface
VolQ
r
xnx pp
x
nx
)1(}{Prob
x – number of successes
n – number of trials
p – probability of success per trial
thresholdP
thresholdrec ePP
}{Prob 2
2 Distribution:
ELECTROMAGNETIC & SENSOR SYSTEMS DEPARTMENT
Random Walk Receive Power
Power samples are separated in space by a distance greater than the
decorrelation length ld ~ l
-30
-25
-20
-15
-10
-5
0
5
10
0 20 40 60 80 100 120 140 160 180 200
Random Walk Sample
Me
an
No
rma
lize
d R
ec
eiv
e P
ow
er
(dB
)
Pthreshold
Complex Standing Wave Pattern
ELECTROMAGNETIC & SENSOR SYSTEMS DEPARTMENT
Random Walk Power Distribution
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 1 2 3 4 5 6 7
Mean Normalized Power
Cu
mu
lati
ve
Dis
trib
uti
on
Sample Distribution
Theoretical Chi-squared
2
2
ELECTROMAGNETIC & SENSOR SYSTEMS DEPARTMENT
Single Sample Probability
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
-30 -25 -20 -15 -10 -5 0 5 10
Mean Normalized Receive Power (dB)
Pro
bab
ilit
y
Probability that Prec Pthreshold per single sample location
Pthreshold
ELECTROMAGNETIC & SENSOR SYSTEMS DEPARTMENT
pRFID Application Of EMRAT
Interrogator to Tag
– Power delivery
– Ray Casting (EMRAT) is effective
Tag to Interrogator
– Data communications
– Multi-path can be considered noise
Ray Casting may be appropriate in
defining volumetric amplitudes
(Noise)
Ray Tracing expected to be more
accurate (Signal to Noise)
– Will require further development
Currently working with ONR and
Drexel University
ELECTROMAGNETIC & SENSOR SYSTEMS DEPARTMENT
Shipboard Demonstration
of pRFID
Objective
– Demonstrate effective and HERO safe shipboard use of pRFID.
Participating members
– NAVSUP, Sponsor
– NOLSC, Program Management
– XIO Strategies, Project Lead
– Alien Technologies, Equipment Supplier
– North Dakota State University, Read Range Assessment
– NSWCDD Q52, HERO Assessment
Execution
– Determine HERO SSD at selected transmit power levels.
– Evaluate read range & reliability at the selected transmit levels.
– Develop system configuration based on above.
– Install system at selected points aboard ship.
– Pass materials through read point and assess functionality.
– Electric eye triggered portal; tags read and data captured by GlobeRanger iMotion software
ELECTROMAGNETIC & SENSOR SYSTEMS DEPARTMENT
SSD (in.) Read Range (in. 100 of 100) ERR* (in.) Read Aperature# (in.)
0 10 10 20
6 24 18 36
12 40 28 56
24 66 42 84
~72 Not Conducted
* Effictive Read Range (ERR) = Read Range - SSD
# Read Aperature Width = 2*ERR
% Based on typical NOT WORST CASE
Hardware Preparation / Tuning
HERO SSD Evaluation
Amp Pwr (dBm) Att (dB) Tx Pwr (dBm) Tx Pwr (W) (Pt) Antenna Gain (dBi) Antenna Gain (Linear) (Gt) EIRP (W) (PtGt) SSD (in)
30 24 6 0.003981072 6 3.981071706 0.015848932 0
30 17 13 0.019952623 6 3.981071706 0.079432823 6
30 13 17 0.050118723 6 3.981071706 0.199526231 12
30 9 21 0.125892541 6 3.981071706 0.501187234 24
30 0 30 1 6 3.981071706 3.981071706 ~72
Read Range Evaluation 50mW / 42.58uW
= 1175 ft2
13 dB Attenuation
12” SSD Selected
ELECTROMAGNETIC & SENSOR SYSTEMS DEPARTMENT
Tagged Assets
MK 46 Torpedo container 54 Inert 5” projectiles MK 82 500lb bomb rack
Partially filled Tri-wall Partially filled “war wagon” Pallet of supplies w/liquids
ELECTROMAGNETIC & SENSOR SYSTEMS DEPARTMENT
Test Results
Port side clearway Container reads 100% (36 of 36) runs on 5 of 6 containers 97% realized on 5” projectile w/diesel forklift
– 100% w/electric forklift….Anomaly??
Cargo Hold / Magazine No diesel lift used below deck 100% (35 of 35) runs on 3 of 5 containers 81% on 500lb bomb rack 69% on tri wall container (suspected instrumentation issue)
Additional opportunity to collect data in elevator 3 most challenging containers selected
– Door open» 100% (20 of 20) reads on 2 of 3 containers
» 40% on war wagon
– Door closed» 100% (20 of 20) reads on all 3 containers
ELECTROMAGNETIC & SENSOR SYSTEMS DEPARTMENT
Demonstration Take Away
Observations
– Occasional stray tag reads picked up from
nearby containers.
– More reflective spaces provided greater read
probability of both containers and items within.
Conclusions
– HERO safe implementation of pRFID in a
shipboard environment is possible.
Business case will depend on desired degree of
asset visibility.