Everything Is Nothing

Everything Is Nothing

  • Submitted By: nrkoko
  • Date Submitted: 09/16/2013 12:46 PM
  • Category: Miscellaneous
  • Words: 646
  • Page: 3
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I See Airplanes:
How to build your own radar system

Eric Blossom eb@comsec.com

More fun with GNU Radio...

What is radar?
● ●

“Radio Detection and Ranging” Watches the reflection of radio waves off of objects and figures out:
– – – –

How far away Velocity of object Bearing (direction) to object Type of object (classification)

A bit of history

First radar 1904 Christian Helsmeyer:

Spark gap; 40 – 50 cm; detected ships

First unambiguous bistatic detection:
– –

Sept 1922, Holt & Young, 50W 60 MHz Observed reflections from trees and wooden steamer (boat) Demonstrated aircraft detection

UK 1935 “Daventry experiment”

WWII, ...

Airport surveillance radar



Radar configurations
● ● ●

Monostatic Bistatic Multi-static (networked)

Bistatic radar

Transmitter & Receiver are at different locations. Original motivations:
– –

Avoiding anti-radiation missles Remote target illumination

Bistatic triangle

Bistatic doppler

Bistatic radar equation

Passive radar
● ●

A subclass of of Bistatic Radar Use somebody else's transmitter!

For example...

The basic idea
● ● ● ● ● ●

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

Don't control signal, but know the general characteristics Obvious choices:
– – –

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

Other choices:
– – –

Primary and/or secondary surveillance

Existence proofs:
● ●

Lockheed “Silent Sentry” Manastash Ridge Radar

Lockheed “Silent Sentry”

Manastash Ridge radar

University of Washington
– –

Prof John Sahr & students Interested in ionospheric phenomenon

● ● ● ● ●

Very simple Two locations separated by 150 km Takes advantage of mountains GPS synced time references Sees stuff up to...

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