# Presentation: 446091

## Mission Aircrew SchoolGlobal Positioning System

**Mission Aircrew School****Global Positioning System**

## APOLLO  GX-55 Global Positioning System Receiver with SAR Maps

## Overview of this Presentation

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

## Global Positioning SystemTheory

**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**

**Notes:**
Polar orbits
Built by the Department of Defense
Uses at least 3 satellites at a time

## 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**

## GPS Theory Continued

**Low power—50 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.)**

## 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.**

## The GPS ReceiverContinued

**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**

##  The GPS ReceiverContinued

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

## The GPS ReceiverContinued

**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.).**

## The Apollo GX55

## 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

## 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**

## 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**

## Control Knobs and Keys

**“****Smart” Keys and “Annunciators”**

**“****Hard” Keys**

**Power**

**“****Large” Knob**

**“****Small” Knob**

## 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 key’s purpose**
**Large and Small Knobs:**
**Change the page of text or the map displayed**
**Select Data Fields**
**Change Data in Selected Fields**

## 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**

## Web Resources

**www.trimble.com/gps**
**Excellent GPS system explanation by the Trimble Corp**
**www.upsat.com/**
**UPS Aviation Technologies—manufacturer 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)**