ADS-B Performance
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© Airservices Australia ADS-B Performance ADS-B Performance Greg Dunstone Technology Development Airservices Australia Greg Dunstone Technology Development Airservices Australia Template Last Updated: 24 February 2005 APANPIRG ADS-B TASK FORCE SEMINAR Nadi , Fiji APANPIRG ADS-B TASK FORCE SEMINAR Nadi , Fiji
Transcript of ADS-B Performance
© Airservices Australia
ADS-B PerformanceADS-B Performance
Greg DunstoneTechnology DevelopmentAirservices Australia
Greg DunstoneTechnology DevelopmentAirservices Australia
Template Last Updated: 24 February 2005
APANPIRG ADS-B TASK FORCE SEMINAR Nadi , FijiAPANPIRG ADS-B TASK FORCE SEMINAR Nadi , Fiji
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Introduction & Overview
• Ground stations• ATC systems
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Typical ADS-B Receive only systemDME OMNI ANTENNA
LOW NOISE AMPLIFIER
SIGNAL PROCESSOR COMPUTER
GROUND STATION
RF
MESSAGES TO ATCMDS= Better than 90 dB
Thales ATM Ground station
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Some sites power by Solar cells
ADS-B takes only 100 watts!
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Typically broadcast 2 / second
Ground Surveillance
ADS-B Ground station
DOWNLINK MESSAGES ADS-B OUT
ASTERIX DATA FORMAT
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Ground station functions• Receive and decode messages
– Position every 0.5 secs– Ident every 5 secs– Velocity every 0.5 secs
• Collate and package – send every second or so
• Remote monitoring capability
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Asterix Cat 21 MessagesAdobe Acrobat
Document
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Burnett Basin Trial Experience
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Qantas A330 ADS-B Operations
QFA794 BNE –CNS F410
QFA715 CNS -BNE F410
QFA924 SYD –CNS F400
QFA925 CNS -SYD F410
ADS-BGround Station
QFA6140 BNE -SYD F410220 Nm
240 Nm
260 Nm
240 Nm220 Nm
280 Nm260 Nm
• Mode S ADS-B gives excellent performance in Australia
Sensis Ground station @ Bundaberg
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BRISBANE TERMINAL AREA RADAR TOWER
ADS-B ANTENNA
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Better than radar
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Radar1030 Interrogate
1090 Reply
At least 4-6 replies required every antenna scanIe: At least 8-10 successful “messages” required
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ADS-B
1090 Message
In 5 seconds – 10 position messages
Only 1 needed for 5 second update !
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ADS-B & Radar Velocity vectors(B200 Sharp turn)
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Toulouse France Ground station
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ADS-B tracks
Melbourne Area
Evening 16 Feb 2005
On screenQFA - QANTASVOZ - Virgin BlueUAE - EmiratesJST - JetstarANZ - Air New ZealandHVN - Vietnam Airlines
50NM range rings
Airlines have ADS-B now
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ADS-B “Noise”POSITION NOISE IN NM
Actual vs Curve Fit
-0.15
-0.10
-0.05
0.00
0.05
0.10
0.15
148.0148.1148.2148.3148.4148.5148.6148.7148.8148.9
Anomaly 2Anomaly 1
STANDARD DEVIATION = 0.0067 NM(Sample = 3000 ADS-B reports)
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Radar & ADS-B Noise distributionVH-QPC System Tracks : ADS-B Position Noise vs Radar Position Noise
0
10
20
30
40
50
60
-1.1 -1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1
Dist in nautical miles from Smoothed Track
Num
ber o
f Rep
orts
ADS-B Position NoiseRadar Position Noise
Samples:240 ADS-B system track reports240 Multi radar system track reportsSame aircraftSame 20 min time interval
ADS-B
RADARError “tails”
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Radar & ADS-B “speed”
ADS-B System Track - Speed
390
400
410
420
430
440
450
460
470
0 50 100 150 200
ADS-B System Track Number
Spee
d in
Kno
ts
Radar System Track - Speed
390.0
400.0
410.0
420.0
430.0
440.0
450.0
460.0
470.0
0 50 100 150 200
Radar System Track Update Number
Spee
d in
Kno
ts
ADS_B RADAR
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Heading noise
Radar System Track Heading Variation from Mean
-7
-6
-5
-4
-3
-2
-1
0
1
2
3
0 50 100 150 200
Radar System Track Update Number
Deg
rees
ADS-B System Track Heading - Variation from Mean
-7
-6
-5
-4
-3
-2
-1
0
1
2
3
0 50 100 150 200
ADS-B System Track Update Number
Deg
rees
ADS_B RADAR
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Integrity
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Integrity data
GPS
Calculate HPL
ADS-BTRANSMITTER
POSITION +
HPL / HILARINC130
POSITION +
NUC (derived from HPL)
ADS-B GROUND STATION
ATC SYSTEM
POSITION +
FOM (derived from HPL)
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HPL / HFOM• HFOM : Accuracy measure assuming that all satellites are
operating correctly
• HPL : Integrity measure. Positional data within this limit with high degree of certainty (10-5/ flight hour)
– Even if a satellite gives false range data– Based on GPS receiver ability to detect satellite false range data given
Satellite geometryRAIM algorithm capabilityAssumption SA on/offWAAS signal receivedGeo satellite received
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Good HDOP / HFOM – Poor HPL
• Good accuracySatellite A
Satellite B
Satellite C
Satellite D
• Poor ability to detect error on Satellite A
• Poor HPL
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Data “quality” (integrity)
HPL =0 Nm
HPL =2 Nm(VSP)
HPL =0 Nm
HPL =20 Nm
HPL =0.5 Nm(VSP)
As good as radar : Display “Good position symbol”Use for separation & safety nets
Low Quality ADS-BNot as good as radar : “Situational awareness symbol”Use for CLAM/RAM
Discard data
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Discussion
More details on Airservices Websitehttp://www.airservicesaustralia.com/pilotcentre/projects/adsb/adsb.htm
Contact me :Greg Dunstone (02)62684286
