GNSS and GBAS Introduction_Honeywell

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GNSS and GBAS Introduction_Honeywell

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Dave Jensen, John Howard
Honeywell, Precision Landing Systems
29-30 Oct 2009
CAAC New Technology Seminar - GNSS
GNSS and GBAS Introduction
􀃆 Honeywell.com
GNSS and GBAS
• Global Navigation Satellite System (GNSS)
– Current implementations, applications
– How it works
– Accuracy, Integrity
• Types of GNSS Augmentation
• Ground Based Augmentation System (GBAS)
– How it works
– Architecture
– Subsystems
• GPS Accuracy and Aircraft Protection Levels
– Un-augmented
– With WAAS
– With GBAS
Dave Jensen/John Howard
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CAAC New Technology Seminar – GBAS 29-30 October 2009
􀃆 Honeywell.com
Current GNSS
GNSS Compass GPS Galileo GLONASS
Origin China USA Europe Russia
Operational 2015 1995 2012 1995
# Satellites NA / 35 30 / 32 NA / 30 19 / 24
21 150 k 22 200 k 23 222 k 19 100 k
• Global Navigation Orbits
21,150 km
12.6h
22,200 km
12.0h
23,222 km
14.1h
19,100 km
11.3h
Satellite Systems (GNSS)
– Have become a global utility
– Provide civilian and military (precise) positioning services
– Consistent, predictable, dependable performance
• Applications for GNSS Keep Growing
– Agriculture, Aviation, Marine, Surveying, Traffic, Timing, Tectonics...
P i i i ti ith h l )
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CAAC New Technology Seminar – GBAS 29-30 October 2009
– Precision navigation ( with help)
􀃆 Honeywell.com
GNSS Theory of Operation
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CAAC New Technology Seminar – GBAS 29-30 October 2009
􀃆 Honeywell.com
GNSS Theory of Operation
• Each satellite transmits its position and a time signal
• The signals are delayed by the distance traveled to user
• From the delay, user calculates distance or “pseudorange” to each satellite
• User determines where there pseudoranges “overlap”
– This is your position!
• GNSS Provides Position, but No Integrity and Limited Accuracy
– Precision application require accuracy
– Safety applications require integrity
• Receiver Autonomous Integrity Monitor (RAIM)
– Provides user with integrity of their position solution
• Used in aircraft receivers
– Requires at least 5 satellites in view
– Receiver excludes 1 or 2 satellites
• Determine a “position” (with satellite excluded)
– Repeat for all satellites in view
– Determine error bound (integrity) of position by
• Discarding outlier “position” solutions
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CAAC New Technology Seminar – GBAS 29-30 October 2009
• Computing variance of “position” solutions
􀃆 Honeywell.com
GNSS Accuracy
• GPS Position Errors can be up to 10 m
• Predominant GNSS Error Sources are:
– Ionosphere (up to 5 m)
– Satellite Position (up to 2.5 m)
– Troposphere (up to 2 m)
– Satellite Clock (up to 2 m)
– Multipath/Reflections (up to 1 m)
– Calculation/Rounding (up to 1 m)
• Poor Geometry of Satellites Increases these Errors
– Geometric Dilution of Precision (GDOP)
• Errors are Measurable, Locally-Correlated, but not Predictable
• Need a System that can Reliably Measure the Errors and Make
Available to Users
– GNSS Augmentation!
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CAAC New Technology Seminar – GBAS 29-30 October 2009
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􀃆 Honeywell.com
GNSS Augmentation Types
• Enhance GNSS Accuracy and Integrity
• Space Based Augmentation System (SBAS)
– Network of ground stations takes local measurements
– Control stations determine errors and transmits error “map” to satellites
– Satellite transmits corrections “map”, integrity data to users
e.g. “WAAS” augments GPS for North America
•Ground Based Augmentation System* (GBAS)
– Ground station determines local errors
– Ground station broadcasts local corrections, integrity data directly to users
e.g. “LAAS” augments GPS for an airport
• Aircraft Based Augmentation System (ABAS)
– Aircraft autonomously determines local errors
– On-board GPS monitors provide integrity
– RAIM concept with additional sensors and monitoring
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CAAC New Technology Seminar – GBAS 29-30 October 2009
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*Only GBAS provides required integrity, accuracy & availability for precision landing.
􀃆 Honeywell.com
Current GNSS Augmentation1
GNSS Compass GPS (SPS) Galileo GLONASS
WAAS (USA)
CDGPS2 (C d )
SBAS NA
Canada)
EGNOS (Europe)
MSAS3 ( Japan)
EGNOS EGNOS
p )
QZSS3 (Japan)
GAGAN (India)
GBAS NA SmartPathTM NA NA
1. As of October 2009.
2. CDGPS is not intended for aeronautical navigation applications.
3. MSAS provides GPS corrections and integrity. While QZSS provides additional high
elevation satellites to improve vertical accuracy.
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CAAC New Technology Seminar – GBAS 29-30 October 2009
􀃆 Honeywell.com
Ground Based Augmentation System
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CAAC New Technology Seminar – GBAS 29-30 October 2009
􀃆 Honeywell.com
GBAS Concept
• Take Multiple GNSS Pseudorange Measurements
– For all satellites currently in view
• Determine Correction (Average Error) of each PR Measurement
– Filtered, then average of PR measurements
• Monitor and Detect Known Threats to GNSS Integrity
– Ensure integrity of PR measurements & corrections
– Alert if integrity cannot be met
• VHF Broadcast Corrections & Error Bounds (Type 1)
– For validated satellites only
– Variance (error bound) of broadcast correction
• VHF Broadcast Ground & Tropospheric Data (Type 2)
– Defines region in which corrections may be safely used
–Provides parameters for tropospheric adjustment
• VHF Broadcast Approach Paths (Type 4)
– All Final Approach Segment (FAS) data
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CAAC New Technology Seminar – GBAS 29-30 October 2009
– No aircraft database required
􀃆 Honeywell.com
GBAS Architecture
Satellite/GNSS
Ground
Aircraft
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CAAC New Technology Seminar – GBAS 29-30 October 2009
􀃆 Honeywell.com
GBAS Architecture
• GBAS is Comprised of 3 Subsystems
– Satellite/GNSS
– Aircraft
– Ground
• Satellite/GNSS Subsystem
– Provides satellite status, position and timing signal
– Has sufficient number of satellites to determine user position
• Aircraft Subsystem
– Applies broadcast pseudorange corrections (PRC’s)
• Computes troposphere adjustment
– Computes position using corrected PR’s only
– Computes deviations from broadcast approach path
– Determines if GLS approach is possible (safe)
– Follows desired approach path to decision height (200 ft)
• Runway visible – continue with GLS approach
• Runway not – Dave Jensen/John Howard
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CAAC New Technology Seminar – GBAS 29-30 October 2009
visible execute missed approach
􀃆 Honeywell.com
GBAS Ground Subsystem
• Ground Subsystem Provides
– Pseudorange corrections for each satellite in view
• With error bound
– System (aircraft) integrity
• Protects aircraft against satellite and/or signal errors
• Protects aircraft against anomalous ionospheric errors
• Protects aircraft against ground subsystem errors
– Approach paths
• Final Approach Segment (FAS) for all runway ends
• No aircraft approach database required
– Local tropospheric parameters
• Necessary to compute aircraft tropospheric adjustment
– Predicted availability
• Availability for precision approaches in next 30 minutes
• Estimates aircraft protection levels against alert limits
Dave Jensen/John Howard
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CAAC New Technology Seminar – GBAS 29-30 October 2009
Single GBAS provides all approaches for an entire airport.
􀃆 Honeywell.com
Augmented GPS Performance1
System Direction
Accuracy
(95%)
Protection Levels
(95%)
GPS2
(Global)
Horizontal
Vertical
2.55 m
4.55 m
50 – 100 m
100 – 200 m
WAAS3 H i t l 0 70 11 16
(CONUS)
Horizontal
Vertical
0.70 m
1.20 m
– m
19 – 31 m
GBAS Horizontal
< 0 50 1 – 3 (Airport)
Vertical
0.50 m
< 0.50 m
m
3 – 5 m
1. Contribution to user position error.
2. April 2009 GPS SPS Performance Report.
3. July 2009 WAAS Performance Report.
Dave Jensen/John Howard
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CAAC New Technology Seminar – GBAS 29-30 October 2009
GPS satellites are ~25,000 km from user!
􀃆 Honeywell.com
Recap
• Global Navigation Satellite Systems (GNSS) Provide Position,
but not Integrity
– Up to 10 m position error
– Aircraft use RAIM to determine integrity
• GNSS Augmentation Improves Accuracy & Provides Integrity
– Continent (SBAS), Airport (GBAS), Aircraft (ABAS)
• GBAS provides Accuracy, Integrity & Approach Paths
– Only GBAS provides accuracy, integrity, availability for precision landing
• GBAS can Achieve 0.50 m Accuracy (95%)
– Aircraft Protection Levels 1 to 5 m
• Questions?
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CAAC New Technology Seminar – GBAS 29-30 October 2009

drjones

支持！正对此感兴趣！

ganxing

xiexie!!!!!!!!!!!!!

xiuhuwang

很想看看是什么内容

超级跑车chaoji

谢谢，先看看

scienceon

very useful to me , thank you!

scienceon

why the google link to   controller arrangement for hilstone  is connected to this page?

lht520yy

Introduction_Honeywell

skycloud1011

Good!Thanks!