Global positioning System GPS

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Global positioning System (GPS)
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Overview
Basic GPS Theory GPS Installation Approach
Overview DGPS
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GPS Constellation
24 Satellites, 6 Orbital Planes, 4 in each Plane,
4 to 5 satellites should be visible anywhere on
earth
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Navigation Coverage
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Geographic Region Database
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GPS Avionics Equipment
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The Equipment
CFR Part 91. 121 and CFR PART 135.144
1. Hand held VFR GPS units.
2. Instrument panel installed VFR GPS units.
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The Equipment
IFR certified GPS must be installed and FAA
approved and certified in accordance with the
following documents 1. Advisory Circulars, AC
20-138 and AC 20-139A, 2. Technical Standard
Order, TSO C-129 and or 3. Technical Standard
Order, TSO C-115a for Flight Management Systems
with multiple navigation sensor equipment. 4.
Wide and local area augmentation GPS, Technical
Standard Order, TSO C-145a and 146a apply. 5.
FAA-P-8000-3, GPS - A guide for the approval of
GPS receiver installation and operation.
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The Equipment

• Properly installed IFR-certificated GPS equipment
  is used for
• 1. IFR Enroute.
• 2. Terminal.
• 3. Nonprecision instrument approach.
• 4. Substitutes for VOR, NDB, DME.

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IFR Requirements for GPS

• 1. FAA approved aircraft flight manual (AFM).
• 2. Flight manual supplement or Approved
  operations manual.
• 3. GPS database must be current.
• 4. RAIM or equivalent method.
• 5. NDB, VOR or DME ground facility may be
  temporarily out of service for primary
  destination airport.
• 6. Ground navigation facility must be
  operational at the alternate airport!

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King KLN 94
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System Equipment
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Garmin 430
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Garmin 530
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Apollo CNX80
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King GNS XLS
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Collins FMS / CDU
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Cirrus SR22 instrumentation
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Basic GPS Theory
"How does this thing work anyway?"
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Theory
1. The GPS navigation system provides world wide
common grid reference based on the earth-fixed
coordinate system (World Geodetic System of 1984
or WGS-84 datum). 2. GPS navigation is based on
ranging and triangulation. 3. Range to the
satellite is known as Pseudo Range. 4. The
position of a satellite is known as its
Ephemeris. 5. Mask range of a satellite is about
5 degrees above the horizon.
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Theory
If we know when the signal departed the satellite
and
exactly where that satellite is in space at that
time.
Distance
we can figure the distance between the
satellite and our position.. then
line of position
A line of position can be drawn our aircraft
will be some where on the line of position!
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2
Theory
To triangulate, GPS measures the distance using
the travel time of a CA Code signal.
(Pseudo Range)

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To measure travel time of the CA Code signals,
the NAVSTAR Satellites use extremely accurate
atomic clocks.
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In addition to knowing the distance to a NAVSTAR
Satellite, the GPS receiver needs to know the
satellites position. (Ephemeris)

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1
Though GPS signals are not affected by weather,
the signals do travel through the earths
atmosphere delaying the CA Code signals.

Triangulation from the NAVSTAR Satellites is the
basis of the system.
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Theory
How many satellites do you need?
4 satellites needed for 3D navigation
5 satellites needed for an approach
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System Accuracy

• The accuracy of GPS position data can be affected
  by
• Equipment characteristics
• Atmospheric propagation (Multi-path errors)
• Inaccuracies of the atomic clock
• Receiver processing (mathematical rounding,
  electrical interference)
• Signal reflection

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Availability

• ExpectationWorld-wide 24 hours a day
• System StatusData messages transmitted by
  satelliteNotice to Airman (NOTAMs)Telephone
  data service 703-313-5910Voice U.S. Coast
  Guard 703-313-5907
• www.navcen.uscg.gov

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Integrity
RAIM
RECEIVER
AUTONOMOUS
INTEGRITY
MONITORING
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Integrity Performance
GS
GS
GS
GS
GS
GS
/- 5.0 MILES
ENROUTE
/- 1.0 MILES
TERMINAL
/- 0.3 MILES
APPROACH
FULL SCALE CDI DEFLECTION RANGE
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Integrity Performance
Approach Transition Operation
Approach Transition Operation within the
Terminal Approach Area (TAA)
Enroute Operation
Approach ACTIVE Operation
CDI Scale 1.0nm
CDI Scale 0.3nm
CDI Scale 5.0nm
CDI Scale 1.0nm
2nm tp FAF (FAWP)
30nm to Airport
MAHP (MAHWP)
FAF (FAWP)
MAP (MAWP)
IAF (IAWP)
5.0nm (Approx..)
5.0nm (Approx..)
A
CDI Scale Gradually Ramps Down From
1.0 to 0.3
RAIM Check
CDI Scale Ramps Down from 5.0 to 1.0
5.0nm (Approx..)
MSG Enunciator Flashes Enable
Approach Press ENT and then Enter Local Alt.
Setting.
At or after the MAP (MAWP), Press OBS HOLD for
the Missed Approach Procedure.
ACTIVE Annunciation
ACTIVE Annunciation
ARM Enunciation
IAF (IAWP)
Active annunciation ON steady
B

NOTE If ACTIVE Enunciator is not Steady at
the FAF (FAWP), DO NOT CONTINUE THE
APPROACH!!!!!!!
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GPS Approach Procedures
Overlay
Procedure Track
Stand-alone
T-Format
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Overlay Approaches
Overlays GPS with a non-precision
approach procedures.
"or GPS" in the instrument approach
title.
May have Computer Navigation Fixes (CNF).
Data base required to have waypoints
represnting IAF (IAWP), FAF (FAWP), MAP
(MAWP) and MAH (MAHWP).
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Overlay Approaches
IAF (IAWP) -- MAP (MAWP) -- MAP (MAHWP).
Missed approach procedure is not auto
sequenced, pilot action is required
(OBS Mode).
Computer Navigation Fix (CNF) 4nm from the IAF
(IAWP) / MAP (MAWP), this is the FAF (FAWP)
inbound.
ACTIVE Enunciator steady at 6nm from the IAF
(IAWP), 2nm from the FAF (FAWP), this is the RAIM
Check.
Established inbound, LEG mode to auto sequence
to the missed approach point
Procedure turn is not Auto Sequenced, fly at
least 6 to 7nm outbound before executing the
procedure turn, pilot action is required (OBS
Mode).
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Stand-Alone GPS Approach
1 minute Procedural Track (Holding
pattern).
New GPS/RNAV procedure.
Modified "T" format.
Missed approach procedure
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Stand-Alone GPS Approach
4 NM Procedural Track
Modified "T" formate
Radar vectors
Fly-by vs Fly-over waypoints.
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Stand-Alone GPS Approach
A
Press OBS/HLD for the LEG Auto Sequencing mode.

Turn anticipation
B
IAF (IAWP)
Press OBS/HLD and proceed manually to execute the
procedural track (Holding pattern).
FAF (FAWP)
Procedural Track (Procedure Turn) or Holding
pattern.
RAIM CHECK
MAP (MAWP)
Automatic waypoint sequencing at these waypoints
to the missed approach point.
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Stand-Alone GPS Approach
Standard "T" configuration.
Procedural Track (Optional).
Terminal Approach Area (TAA).
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Stand-Alone GPS Approach
Modified "T" configuration.
Terminal Approach Area (TAA)
not depicted.
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(No Transcript)
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ILS Approach

GPS Defaults or not??
GPS Auto Sequence??
MAP - GPS or VHF??
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Precision GPS Approach
Global Landng System (GLS)
Transponder Landing System (TLS)
Differential GPS (DGPS)
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Wide Area Augmentation System (WAAS)

Local Area Augmentation System (LAAS)
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Wide Area Augmentation System (WAAS)
The WAAS system covers wide geographic areas.
The WAAS control system is a network of a Master
Control Station (MCS), 5 signal monitoring
stations and 3 Ground Uplink Stations (GUS) to
complete the control segment. WAAS broadcast
messages improve GPS signal accuracy from 100
meters to approximately 7 meters.
Geostationary Communications Satellite
(GEO)
WAAS Signal using GPS Frequency 1575.42 MHz
Navstar Satellite(s)
Surveyed Ground Reference Stations
Ground Uplink Station(s) (GUS)
Wide Area Master Station (WMS)
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Local Area Augmentation System (LAAS)
NAVSTAR Satellites
LAAS Ground Station
Differential correction messages
The LASS system focuses service on a local area
approximately a 20 - 30 mile radius of an
airport. LAAS broadcasts its correction
messages via VHF radio data link.
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Local Area Augmentation System (LAAS)
Precision GPS Approach
An aircraft tracking within 1nm of its course
may expect 3 to 5 meters course tracking
accuracy.
Required accuracy for a CAT I Precision
Instrument Approach at Decision Height (DH) is
17.1 meters horizontal and 4.1 meters vertical.
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The WAAS will provide guidance for en route,
terminal, and approach operations. WAAS sends
differential correction and integrity messages to
aircraft via geostationary earth-orbit (GEO)
satellites.
Wide area augmentation System (WAAS)
Local area augmentation System (LAAS)
LAAS will meet guidance requirements for more
stringent approach and surface operations. LAAS
is intended to complement WAAS navigation for all
phases of flight. This means at locations where
WAAS is unable to meet existing navigation and
landing requirements LAAS will be used to fulfill
these requirements.
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Cockpit Resource Management (CRM)
Data entry verification after loading?
Lots of heads-down time!
Whos watchn the store?
Situational awareness!
Rely too much on GPS???
High intense workload!
Loss of pilot skills autopilot usage?
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Review
Approach Sequence IAF (IAWP) FAF (FAWP) MAP
(MAWP) MAP (MAHWP)
Current Database RAIM Enroute Terminal (SIDS
STARS)
ATC Clearance Intermediate Segment Short
Approach Training Requirements WAAS LAAS
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The End