I See Airplanes:
How to build your own radar system
Eric Blossom eb@comsec.com
More fun with GNU Radio...
What is radar?
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“Radio Detection and Ranging” Watches the reflection of radio waves off of objects and figures out:
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How far away Velocity of object Bearing (direction) to object Type of object (classification)
A bit of history
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First radar 1904 Christian Helsmeyer:
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Spark gap; 40 – 50 cm; detected ships
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First unambiguous bistatic detection:
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Sept 1922, Holt & Young, 50W 60 MHz Observed reflections from trees and wooden steamer (boat) Demonstrated aircraft detection
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UK 1935 “Daventry experiment”
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WWII, ...
Airport surveillance radar
PAVE PAWS
Busted!
Radar configurations
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Monostatic Bistatic Multi-static (networked)
Bistatic radar
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Transmitter & Receiver are at different locations. Original motivations:
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Avoiding anti-radiation missles Remote target illumination
Bistatic triangle
Bistatic doppler
Bistatic radar equation
Passive radar
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A subclass of of Bistatic Radar Use somebody else's transmitter!
For example...
The basic idea
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Use other people's transmitters Use multiple coherent receivers One or more Tx and/or Rx locations Watch reflections Do a bunch of math Detemine position and velocity
Choice of transmitter
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Don't control signal, but know the general characteristics Obvious choices:
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Broadcast FM (100 kHz wide) Analog and/or digital TV (6-8 MHz wide) GSM cellular / UMTS High power satellites (DBS) GPS satellites Existing radar transmitters
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Other choices:
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Primary and/or secondary surveillance
Existence proofs:
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Lockheed “Silent Sentry” Manastash Ridge Radar
Lockheed “Silent Sentry”
Manastash Ridge radar
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University of Washington
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Prof John Sahr & students Interested in ionospheric phenomenon
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Very simple Two locations separated by 150 km Takes advantage of mountains GPS synced time references Sees stuff up to...