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School of Electrical EngineeringTel Aviv University
Single Antenna Geo-location Based on Signal Structure
Elad Tzoreff, Ben-Zion Bobrovsky, Anthony J. Weiss
(Free space Radio Signals)(Free space Radio Signals)
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School of Electrical EngineeringTel Aviv University
Background: Common Geo-location methods
Direction of Arrival (DOA)
Time Difference of Arrival (TDOA)
Differential Doppler (DDOP)
Received Signal Strength (RSS)
Finger Printing
Combinations of the above
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School of Electrical EngineeringTel Aviv University
DOADOA
RSSRSS
DDOPDDOP
TDOATDOA
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School of Electrical EngineeringTel Aviv University
Common Geo-location methods
Multiple sensors Synchronization between sensors Communication between sensors
All these mean: Complex system architecture Expensive support systems
Synch beaconSynch beacon
sensorssensors
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School of Electrical EngineeringTel Aviv University
We are interested in simplifying geo-location system, but how?
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School of Electrical EngineeringTel Aviv University
Observation
Most radars are periodic or at least predictable:
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School of Electrical EngineeringTel Aviv University
Digital Communication Signals
Communication Carrier is periodic
Communication symbols appear periodically
Communication synch frame appear periodically
Spreading code is periodic
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School of Electrical EngineeringTel Aviv University
Basic Idea and Advantages
Use a single moving receiver for location Low costLow weightEasy to hide (small, passive, moving)Simple to implementNo synch. between sitesNo data link between sitesCan enhance existing system
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School of Electrical EngineeringTel Aviv University
Potential Platforms
UAVUAV
UAVUAV
Localization shellLocalization shell
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School of Electrical EngineeringTel Aviv University
Localization Based on Signal Structure
A B
Time
Time
DTOA
Receiver path
Transmitter
The periodicity as observed at A
The periodicity as observed at B
Observed at A
Observed at B
Ext rapolation
Receiver moving from A to B
{ {{
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School of Electrical EngineeringTel Aviv University
TDOA Lines of Position
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School of Electrical EngineeringTel Aviv University
The LOPs Associated with DTOA
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School of Electrical EngineeringTel Aviv University
DDOP Lines of Position
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School of Electrical EngineeringTel Aviv University
LOPs Associated with DDOP
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School of Electrical EngineeringTel Aviv University
Potential Obstacles
Transmitter Oscillator instability
Receiver clock instability
Receiver Position inaccuracy
TDOA/DDOP measurements errors (Noise, BW,
Multipath)
Transmitted signal is too short
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School of Electrical EngineeringTel Aviv University
Oscillator Imperfection Timing Errors
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School of Electrical EngineeringTel Aviv University
Oscillator InstabilityTiming errorTiming error
error due to frequency skew
( ) random errort
hh = Random error intensity = Random error intensity
• Voltage controlledVoltage controlled
• Temp. compensatedTemp. compensated
• Oven compensatedOven compensated
1min, ( ) 8 [ ]
10min, ( ) 25 [ ]
t t ns
t t ns
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School of Electrical EngineeringTel Aviv University
Sensor trajectory 6 KmSensor trajectory 6 Km
Signal period 10 msSignal period 10 ms
Sensor speed 300 m/sSensor speed 300 m/s
Simulation ResultsSimulation Results
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School of Electrical EngineeringTel Aviv University
Heat Map straight trajectory
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School of Electrical EngineeringTel Aviv University
Heat Map Curved Trajectory
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School of Electrical EngineeringTel Aviv University
At High SNR Accuracy is Limited by Oscillator Instability
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School of Electrical EngineeringTel Aviv University
The Slower the Receiver Moved the Larger the error
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School of Electrical EngineeringTel Aviv University
For Good Oscillators the Accuracy is Determined by SNR
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School of Electrical EngineeringTel Aviv University
Thank you, Questions, Comments or Thank you, Questions, Comments or remarks?remarks?
