Transcript Agilent RF sensor networks for Improved Detection and

Aerospace and Defense
Symposium 2009
RF Sensor Networks
For Improved Detection and
Geolocation
Robin Wang
RF/uW and A/D Application Engineer
RF Geolocation Techniques Used Today
– Direction Finding (DF)
• The de facto standard approach today
• Measures angle of arrival (AoA) to generate a Line of Bearing
• Triangulation of signal from two or more DF systems
– Time Difference of Arrival – TDOA
• Determine difference in time a signal arrives at multiple receivers
• Triangulation from 3 or more sensors
• Used today for cell phone location in US E911 (uses cooperative approach)
– Signal Amplitude Comparison
• Stronger signal ~ closer proximity
• Poor geolocation accuracy - need high monitoring density
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RF Sensor Networks
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Synchronized measurements involving two or more sensors
System Performance Parameters, not just receiver specs.
Software-Defined Sensors
Supports Partitioning
Manageable
Expandable
Fault Tolerant
Sensors
• Just enough
performance
• Low Price
• Easily Installed
• Remotely managed
Example Network Architecture
Location 3
(Mobile)
(Existing) Surveillance or DF System
Location 1
Ops Client
Host Server
VPN Router
User
Intranet
VPN Router
Wireless
Broadband
Public
Internet
Remote Client
VPN Router
Location 2
Location ‘n’
GPS Synchronization
Power vs. Time
Power
Measured by GPS synchronized receivers
at four different locations in London
Time
This over-the-air measurement
clearly shows three different
time slots. From this plot we
observe:
1.The relative powers change
from slot-to-slot indicating
three different transmitters.
For example blue is higher
than yellow in the second slot,
and lower in the first.
2. The power is fluctuating
differently at each receiver for
the middle slot. Power
fluctuation is probably caused
by fading from a moving
transmitter.
IEEE-1588 Network Based Time Synchronization
• Invented by Agilent
• Implemented in N6841A RF Sensors
• Provides alternate method of
synchronization when GPS can’t be used
• Indoor Environments
• GPS frequency monitoring
• GPS jamming
• Time accuracies similar to GPS
(10’s of nsec or better)
• 1588 Boundary- and Transparent-clock
switches available from several vendors
1588 Switch
Master
Clock
(or sensor as
Master)
Product Overview
N6841A
Remote RF Sensor
N6841A RF Sensor
GPS antenna
Key Features
• Indoor and outdoor spectrum
monitoring and geolocation
• 20 MHz to 6 GHz
• 20 MHz of information BW
• Integrated GPS for time
synchronization and location
(outdoor)
• Network synchronization < 20
nS accuracy (indoor)
• Sealed Weatherproof
Enclosure (rated IP67) inc
mounting kit
• Low cost, for deploying sensor
networks
GPS Power Data
RF Inputs
RF Sensor Key Benefits:
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Low-Cost
Weatherproof: IP 67!
Synchronization < 20 nS!
Proven Reliability (<2% returns)
SMS and SMT For Expandable Sensor Networks
File Edit Tools Help
SMT
PC
PC
Sensor List
1. Scarborough
2. 192.168.1.23
3. Mississauga
4. St George
Start
Stop
Status
Configure
Surveyor
My App 1
Skagit Demo
Surveyor
3rd Party App
Surveyor
API
API
N6841A
Sensor
SMS
N6841A
Sensor
API
N6841A
Sensor
SMS – Sensor Management Serv
SMT – Sensor Management Tool
Targeting Market
Example Target Customer : Frequency Regulators
• Responsible for Managing the RF Spectrum, issuing
Licenses.
Resolving unlicensed use and interference problems.
– They need it : Demand for Spectrum increasing.
Higher population density and more services.
More unlicensed spectrum often brings problems.
Drive to reduce staff and costs.
– Their old kit doesn’t do the job: More challenging
standards, networks of lower power devices more
sensitive to interference.
– Competitive Opportunity : They want to replace
but traditional approaches too expensive.
Other Target Customers
• Thinking of ‘out-door’ users
• General remote Monitoring. Checking
transmitters and other operational services
etc. Police Radios etc.
Probably a VSA/Signal Surveyor Opportunity.
• Airport Perimeter
Interference to Airport Services (ATC, Landing
systems etc.) Opportunity for large network
of Sensors.
Application Software
N6820E Signal Surveyor Software
N6820E Signal Surveyor Software
Software Features and Hardware Requirements
Spectral Shape Correlation (wideband part of USD)
Remote Programming Interface
User Programming (Thresholds, Features, Filters, Alarm
Tasks, Handoff Rx, Menus, Panes)
Handoff Receiver Interface
Direction Finding Interface
Modulation Recognition
IQ Time Snapshots
Alarms
Feature Extraction
Thresholds
High Speed Search
N6820E Signal Surveyor Software
Modulation Recognition (Option MR1)
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FSK
3-level FSK
4-level FSK
8-level FSK
Analog FM (includes multilevel FSK not shown above)
– MSK (includes GMSK and
Offset (aka Staggered) QPSK)
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BPSK
QPSK (includes DQPSK)
/4 QPSK (incl. /4 DQPSK)
8 PSK
16 PSK
V.29 Modem
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– Pure Carrier
16 QAM
– Noise
32 QAM
– Unknown Digital
64 QAM
(reports symbol rate of other
digital modulation formats)
128 QAM
256 QAM
Modulation
AM
Attributes
AM DSBSC
– Frequency
LSB
– Bandwidth
– SNR
USB
– Symbol Rate
OOK (aka ASK)
– Frequency Deviation
4PAM (aka 4-level ASK)
Manual Morse
Machine Morse
N6820E Signal Surveyor Software
Universal Signal Detection
Shape
New frequency domain
power correlation algorithm
(iDEN)
Peaks
New frequency domain
peak detection algorithm
(great for n-FSK)
Limit Lines
Simple mask
(NADC)
(HF ALE)
N6820E Signal Surveyor Software
Energy Detection Thresholds
Level
threshold
Auto (noise-riding)
threshold
Environment
threshold
Noise threshold
N6820E Signal Surveyor Software
Energy History
N6820E Signal Surveyor Software
Capturing a Snapshot
Snapshot captures can be triggered…
Automatically from an alarm
Manually by pressing the snapshot
marker button.
Recording and Playback
Signal Data Post-processing options
89601 VSA software
(no hardware mode)
N6841A RF Sensor
N6829B Snapshot Radio
N6820E software
Time series
Snapshot Files
•N6820E software and VSA software share a
common capture file format.
N6854A Geolocation How it all looks…
Geo measurement
results
Geo measurement
setup parameters
Geo measurement
results plotted on the
SMT map.
Historic measurement
database
Time domain, spectrum and
correlation displays
How it looks in Google Earth (using export KML)
How it looks in Surveyor 4D
Geo measurement
setup parameters
Geo measurement
results
Agilent Spectrum Visualizer
89601B Vector Signal Analyzer software
N6854A London Demo System
N6854A Geo Server
Winnersh, UK
Client Demo PC
Agilent Office
Battersea
Southwark
DSL
Holborn
Public Internet
Agilent
Intranet
Peckham
Agilent Firewall
UMTS
/GPRS
VPN Router
Shoreditch
Network Server
Everett, WA USA
Network Server
Santa Clara, CA USA
Stratford
Excel
Rotherhithe
Sensor Network Deployment
17 km
17 km
Sensor Installations
Peckham
Battersea
Small Area - Town
• Typically more Sensors
required particularly for
PMR radios.
• Similar site deployments
• Height
• Open area
Battery-powered Accessory Kit!
•6
to 8 hour operation
• Lightweight and rugged
• VSA, Surveyor 4D, Agilent
Spectrum Visualizer , SMT
supported
•
Backpack, battery, charger
• Antenna Kit
• All cables
• GPS Patch antenna for
shoulder mount
Wide Area Solution
– Sensors separated 2 to 10km apart
depending upon signals of interest.
(2km more PMR, 10km more Unlicenced FM)
– Typical Frequency Regulator
Application
– We have a setup in conjunction with
UK customer we can demonstrate by
prior arrangement.
Small Area – Town
: Hybrid Result
Small Area – Airport– On-site PMR Radio
Locate PMR radios
• 400MHz narrow-band signal
• Measurement automatically triggered
on Transmission.
Airport Examples – Off-site Interference
Broadband signal interfering with PMR
radios
• Emission outside sensor area so
direction shown.
• Location could be obtained with
sensors deployed outside the Airport
(W-CDMA operator)
Success Story #1: N6854A London Demo System
• The London Demo
System has
permanently installed
N6841A RF Sensors
• Usage is spectrum
monitoring and
interference location
• Real life case studies of
located interferers
N6854A Geo Server
Winnersh, UK
Battersea
Southwark
DSL
Holborn
Public Internet
17 km
• From customer:
Peckham
– “TDOA is working
very well”
– “Performance
consistently
exceeding
expectation”
UMTS/
GPRS
Shoreditch
Stratford
Excel
Rotherhithe
Success Story #2 Airport GPS Interference
 Interference on GPS L1 frequency
 Very low power level; jammer was
present but difficult to detect
 Intermittent occurrences
 Tools used:
 Spectrum Analyzers & Field Fox
 N6841A RF Sensor / N6820A Signal
Surveyor S/W
 N6854A Geolocation Server System
Fixed Sensor locations
Mobile Sensor locations
Success Story #3: Geolocation of the GPS Jammer
RF Interference (RFI) confirmed via field observations
RFI not present
Starburst
appears to
detect GPS
Satellites
Illegal device
located
Success Story # 4 Jakarta Demo System
Success Story # 5 Pakistan University Good
Summary
• RF Trends Drive paradigm shift in monitoring
– Can’t buy/build receivers with enough performance
– Receiver performance can’t solve co-channel signal problems
• Network Trends support paradigm shift
– Transfer data to common processing point for processing gain
• Synchronization
– Required because of dynamic signal environment
– Required for geolocation
• Focus on system price/performance
– Sensor density is important
– Trade off density with price/performance of individual receivers