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Tracking Aircraft With GNU Radio

Nick Foster9/14/2011

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What Is ADS-B?

Automatic Depenent Sur!ei""ance-Broacast

A#$ o% the %uture &FAA Ne't(en pro)ect*

+e,uire on most A$ in S . 2020 a"rea re,uire in urope

Auments primar sur!ei""ance raar &ADS-B 3ut* (i!es pi"ots their on raar picture &ADS-B In*

#ransport "aer not phsica" &3SI "e!e" 4*

Se!era" 567 "aer imp"ementations

A#

Mode S Extended Squitter

8D moes 2/4

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ADS-B enhance A#$ sstem

10:0;6 ;oe $ > ;oe S*

ni,ue" ienti%ies everyaircra%t . air%rame ID

No meia access contro" at a"" transponers )ust step on each other &@F+I#*

ADS-B uses @e'tene s,uitter 112 .it packets

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+ecei!er 5er%ormance an +esu"ts

Aircra%t success%u"" tracke %rom 2E nautica" mi"es aa

#pica" rane 100-1E0nm epenin on irection an a"titue

Setup

S+51

DBS+=

;ini-$ircuits NA

1090;6< SAW %i"ter

Interestin aircra%t hear Air Force 3ne B"ue Ane"s $-1:0AWA$S

(-24 0 0.000000) Type 17 subtype 04 (ident) from adfdf8 with data AF1(-26 0 0.000000) Type 4 (short surveian!e atitude repy) from adfdf8 at 112"ft(-2" 0 0.000000) Type 0 (short #-# surveian!e) from adfdf8 at 112"ft (speed$00-600%t)

(-24 0 0.000000) Type 11 (a !a repy) from adfdf8 in repy to interro&ator 0

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;u"ti"ateration

ADS-B is reat an a"" .ut on" :0G comp"iance in the S

What oo is a co""ision a!oiance sstem hich inores0G o% the tra%%ic?

What a.out interestin nonparticipatin aircra%t &AF1 B"ue

Ane"s etcH*? ;oe S pro!ies a uni,ue air%rame ID to i%%erentiate rep"ies

6per.o"ic positionin .ase on #D3A )ust "ike (5S

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T2

T3

T1

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;a.e its not "ike (5S a%ter a""

We et a %ree .it o% kno"ee a"titue

ets us mu"ti"aterate ith three rather than %our stations&a".eit ith poor eometr*

'tra @recei!er "ocate at arths center ith simu"ate#D3A to knon a"titue

Non-snchroni

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#he ine!ita."e math

Iterati!e "east s,uares so"!er .ase on (5S e,uation

So"!er operates on the partia" eri!ati!es o% the pseuoranes usin Netons ;etho

@'tra station compute usin one stations "at/"on an the aircra%ts knon a"titue pseuorane chanes "itt"e ith "at/"on chanes ue to sma"" anu"ar separation

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+esu"ts#ir!raft heard for !o!% drift estimate' ab!64*+ a8"22b+

a82aa!+ a*821*+ a6a!$*+ a8a7$d,Tota reports used' 640 over $48."* se!ondsdrift from 0 reative to station 0' 0.000ppmdrift from 1 reative to station 0' ".477ppmmean offset from 0 reative to station 0' 0.000 se!ondsmean offset from 1 reative to station 0' 2.21* se!ondsRMS error in TDOA: 209.9 meters

Better c"ock ri%t estimation&%i"terin instea o% mean*ou" pro!ie sini%icant"reuce error

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Future impro!ements

+ea"-time mu"ti"ateration instea o% post-processin

Better c"ock rate estimation

Ja"man %i"ter %or position estimation

$5 optimi

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Cuestions

$oe is at ithu.Hcom/.istromath

$ome see me %or a "i!e emo on a S+5 B100