Mission Aircrew School Global Positioning System

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Mission Aircrew SchoolGlobal Positioning System
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APOLLO GX-55 Global Positioning System Receiver
with SAR Maps
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Overview of this Presentation

• GPS Theory
• GPS Receivers
• GPS Receiver Features
• GPS Receiver Controls and Functions
• Summary
• GPS Resources on the Web

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Global Positioning SystemTheory

• 24 satellites in 6 orbital planes
• First satellite launched in 1978
• Full constellation achieved in 1994
• 4 satellites in each plane
• 20,200 km high orbits
• 12 hours per orbit

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GPS Theory Continued

• DOD system initially for military use
• Civilian use permitted later
• Must see at least 3 satellites for 2D Nav
• Must see at least 4 satellites for 3D Nav
• Usually sees 5 to 8 satellites

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GPS Theory Continued

• Low power50 watts or less
• Civilian GPS uses frequency of 1575.42 MHz
• Three components comprise GPS system
• Satellites
• Ground Control Stations
• Receivers
• GPS signals are subject to the usual radio signal
  propagation errors and errors unique to the
  system (ie, satellite geometry, orbital errors,
  etc.)

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The GPS Receiver

• Processes signal information from satellites to
  calculate the exact location of the receiver,
  including altitude
• Re-computes position/altitude continuously
• Uses position information, and change-of-position
  information, for calculations of speed, bearing,
  track, distance, ETE, ETA, sunrise and sunset,
  etc.

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The GPS ReceiverContinued

• Internal Databases
• Airports and Airport Information
• Navaids (VOR and NDB)
• Intersections
• User-defined Waypoints
• Terrain Clearance Features
• Airspace and Special Use Airspace
• SAR Maps and Grids

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The GPS ReceiverContinued

• Built-in databases permit
• Easy entry and retrieval of waypoints and
  waypoint information
• Automatic display of airspace warnings
• Moving maps

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The GPS ReceiverContinued

• GPS signals are radio signals, so they are
  subject to all the typical errors associated with
  radio signal propagation in addition to errors
  unique to the gps system.
• The receiver by itself has no direction or
  altitude sensing capabilities. In the absence of
  useable signals, the receiver will display
  erroneous information or will display only
  warning messages.
• Use of the receiver does not relieve the pilot of
  maintaining position awareness through other
  available methods (charts, VOR, etc.).

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The Apollo GX55
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GX55 Features

• Internal Database
• Airports and Airport Information
• Navaids (VOR and NDB)
• Intersections
• User-defined Waypoints (up to 500)
• Terrain Clearance Features
• Controlled and Special Use Airspace
• Search and Rescue capabilities
• SAR Grids (identical to gridded sectionals)
• SAR Search Patterns
• Parallel Line
• Creeping Line
• Expanding Square

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GX55 Features Continued

• Flight Plans
• Stores up to 30 reversible flight plans of up to
  20 legs each
• Automatic sequencing of legs/waypoints
• Message Function
• Flashing MSG indicator
• Continues until all messages are read
• Requires immediate attention
• Warnings
• Important flight data/information

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GX55 Features Continued

• Direct-To Navigation Function
• Nearest Waypoint Search
• Moving Map and Text Displays
• Message Function
• Flashing MSG indicator
• Continues until all messages are read
• Requires immediate attention
• Warnings
• Important flight data/information

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Control Knobs and Keys
Power
Smart Keys and Annunciators
Large Knob
Small Knob
Hard Keys
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Controls and Functions

• Power Switch
• Buttons
• 7 large Buttons are called hard keys
• Right side of the display panel
• Always perform the same function
• 5 small buttons are called smart keys
• Located below the display panel
• Function can change
• The annunciator above each smart key labels the
  keys purpose
• Large and Small Knobs
• Change the page of text or the map displayed
• Select Data Fields
• Change Data in Selected Fields

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SUMMARY

• GPS - Very Accurate
• GPS Receivers (Becoming User Friendly)
• Sophisticated displays
• Large databases
• Wealth of information and assistance
• Navigation made easy
• Position awareness is more critical than ever
• GPS system is not fail proof or fool proof
• GPS ease of use and accuracy can lead to
  over-confidence and over-reliance on the system

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Web Resources

• www.trimble.com/gps
• Excellent GPS system explanation by the Trimble
  Corp
• www.upsat.com/
• UPS Aviation Technologiesmanufacturer of the
  GX55
• Downloads available
• User manual
• Installation manual
• Quick reference guide
• Simulator software (without SAR function full
  version that includes SAR is for sale, or it can
  be obtained from Iowa CAP)