Wide Area Multilateration Demonstration System Rudolf Seller, Ádám Szüllő Budapest University of Technology and Economics Radar Research Group.

Wide Area Multilateration Demonstration System

Rudolf Seller, Ádám Szüllő

Budapest University of Technology and Economics

Radar Research Group

WAMLAT

• Passive distributed radar system to improve ATC reliability

• Wide-area coverage (>10km diameter)• Multiple receivers• Synchronization challenge• GPS based synchronization

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WAMLAT System

• GPS based synchronization• Data transfer via Ethernet• Server

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Geometry of the Receivers

• Multilateration is nonlinear• Location dependent position

estimation accuracy• Zone defined

by the receivers

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Synchronization

• GPS Disciplined Oscillator (GPSDO)• No physical clock distribution network• Tens of nanosecond accuracy

• Long term time difference measurement between two GPSDOs:

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Arrangement of the Receivers

• Across and around the city of Budapest• Not optimal geometry

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Results

• Persistent displaying• Fligth information from http://www.flightradar24.com

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Results

• Mode A and Mode C based multilateration has high false detection rate

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Results

• Only Mode S based multilateration

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Results

• „Invisible” aircraft

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Location dependent accuracy

• Multilateration is nonlinear

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Accuracy of the system

• Multilateration compared to ADS-B• ADS-B accuracy is questionable

(eg. systematic error because of delay)• Accuracy estimation based

on longterm dataset• Median error is 128 meters• Estimated accuracy is

150 meters

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Future work

• Develope tracking algorithm

• Expand the system nation-wide

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Thank You!

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