GPS Navigation Using the Apollo GX-55

GPS Navigation Using the Apollo GX-55
May 2008

Motivation GPS is a powerful tool for search and rescue
Allows very precise search patterns Makes manageable what would otherwise be very difficult patterns Expanding square at any angle Creeping line along a course Offset route searches Grid searches over indistinct terrain GPS should be our primary tool for Search and Rescue navigation GPS is of course also very handy for general navigation

Before we begin… How does one learn to use GPS?
This presentation provides a good foundation of knowledge, but it will be forgotten quickly if not used Hands-on practice is the only way to become proficient Start out with the software simulator, if possible The simulator has limitations and a few bugs, but it is worthwhile Information on how to acquire the simulator can be found at the end of this presentation Download the “shorthand guide” from the wing website and keep it with your mission kit Practice with the real device in flight

Before we begin… After you’ve had some practice, consider reviewing the GPS user manual (or study this presentation again) When you think you have it down, try teaching someone else!

GPS Navigation Using the GX-55 Course Outline
This presentation is organized in six parts Fundamentals of GPS Navigation Introduction to using the Apollo GX-55 Basic tasks with the GX-55 GX-55 search patterns Safety issues Using the GX-55 simulator software

Part 1 – Fundamentals of GPS Navigation
How it works: The basics Accuracy Describing locations

How it Works – The Basics
Spaced-based system (unlike Loran or VOR) ‘Constellation’ of 24 satellites in six orbital planes 21 active satellites plus 3 operating spares In “High” orbit of about 12,000 miles Each circles the Earth about every 12 hours

GPS satellites transmit information “Pseudo-random” code with time information Satellite orbital position data “Almanac” data “Ephemeris” data Updated atmospheric models GPS receiver uses this data to figure out what time it is and what time the signals were sent

GPS receiver measures distance to satellites by determining the amount of time that the radio signal takes to travel from each satellite Each distance measurement effectively defines a sphere around a satellite Multiple satellites must be used to determine a position Given two satellites, two sphere intersect to determine a circle Given three satellites, a sphere and a circle intersect to determine two points A fourth satellite can determine a positive 3D position

Accuracy A complex question The short story
DOD has a 66 page document describing the performance of GPS Standard Positioning Service (SPS) The short story Garmin states that their GPS receivers “are accurate to within 15 meters on average” Typically about 6 to 12 Meters accuracy can be seen

Accuracy Accuracy and reliability is actually a complex subject. There are many factors that can impact system. Receiver errors Atmospheric (ionosphere) errors Solar activity (sun spots and solar storms) Location of receiver (some parts of the Globe get better coverage than others) Orbital errors (inaccuracies in the reported orbital position) Poor satellite geometry (satellites lined up or bunched up) Limited number of satellites in view Satellite malfunctions (or satellites taken out of service) “Multi-path” errors (radio signal reflections) Results vary hour by hour, day by day

Accuracy There is a substantial difference between typical accuracy and worst-case accuracy Described as a statistic: x% had an error of y meters or less Typical 95% horizontal error results for a typical day: Global average 7.8 – 8.3 meters Average for worst site (on globe) meters Errors worse than 30 meters are possible given the potential for various atmospheric conditions and receiver faults and the possibility that satellites can be taken out of service

Accuracy and “Selective Availability”
Past feature of GPS SPS that purposefully degraded accuracy of position determination for non US-military use Civilian accuracy was typically about 100 meters under Selective Availability SA was discontinued May 1, 2000 Has not been used since It's been replaced by “selective deniability,” which allows the US military to geographically designate areas in which to degrade GPS quality.

Comparing Accuracy with and without SA – A sample
The plots show that SA causes 95% of the points to fall within a radius of 60.7 yards. Without SA, 95% of the points fall within a radius of 7.9 yards.

Comparing Accuracy with and without SA – Recap
Before, with 100 meter typical accuracy allowed you to identify what stadium you were in Now with 6-12 meter typical accuracy, you can tell about which yard line you are on

Accuracy – WAAS Wide-Area Augmentation System
Designed specifically for aviation Commissioned by FAA in 2003 Uses ground stations and satellites 25 ground stations cover the entire US and parts of Canada and Mexico Augments GPS Standard Positioning Service Provides better integrity and accuracy Typical accuracy of 3-5 meters horizontal, 3-7 meters vertical Can be used for precision approaches WAAS is not a feature of the Apollo GX-55 used by CAP

Describing Locations A Choice to Understand
We describe latitude and longitude normally using degrees and minutes When dealing with fractions of minutes there is, however, a choice There are essentially two options: One can use seconds (of which there are 60 in one minute) One can use decimal-minutes (i.e. tenths and hundredths of a minute) Many GPS units can be configured to display one way or the other

Describing Locations CAP Standard Method
The standard we will use in CAP is degrees and decimal minutes Example: 45 degrees 35.4 minutes North 93 degrees 42.2 minutes West This is the standard way the Air Force provides coordinates to us for search and rescue This is also the way our GX-55 normally displays position information In CAP we will not usually use “seconds” unless working with another agency that wishes to do so.

Describing Locations Communicating with Others
The seconds vs. decimal minutes question is a big source of confusion even within our own ranks Some people erroneously say “seconds” when they mean “hundredths of a minute” Some people say “point” or “decimal” when they should have said “minutes” and “seconds” Take nothing for granted when getting information Be accurate and clear when giving information Especially when working with other-agencies, triple-check all coordinates to make sure we’re all speaking the same language The Coast Guard Auxiliary normally uses Degrees-Minutes-Seconds as their standard way of describing positions, but they will use the word “decimal” or “point” to separate the three parts of the coordinate

Describing Locations Yet Another Approach to be Aware of
Some GPS units (including the GX-55) also offer the option to display position information using Universal Transverse Mercator” (UTM) An alternative to using degrees and minutes Beyond the scope of this course We will not use this

Part 2 – Introduction to using the Apollo GX-55
Equipment overview The controls and function/page hierarchy Review terminology Tour of display pages – how to read displayed information

Our Equipment: Apollo GX-55
Extensive Database Scrolling Map Display Search and Rescue Functions

GX-55 Controls Power Switch “Hard” keys “Smart” Keys & “annunciators”
“Small” Knob “Large” Knob

Large & Small Knobs Moving between pages Entering Data
Large knob selects most main pages Small knob selects sub pages Different scale maps Sub-pages in set-up areas Entering Data Large Knob moves cursor Small Knob changes word or character at cursor

Hard Keys NAV Navigation display pages, flight plan setup, etc.
MAP Map display pages NRST Pages with nearest waypoints INFO Database information pages SEL Select Make a cursor appear so you can change a value on a page When a question is being asked, make the cursor disappear, effectively responding “no” to the question Enter Complete some data entry action Also used to answer “yes” in response to a question D “Direct-To” (short-cut flight-plan from current location)

Function/Page Hierarchy: Getting to the screen page you want
Main hierarchy: Hard key (example: MAP) Large Knob (example: Map Setup) Small Knob (example: Route Line, Map Orient, & Map Reference)

Function/Page Hierarchy: Getting to the screen page you want
Other paths: Hard key (example: NAV) Smart key (example: FPL – Flight Plan) Large knob (example: Create new flight plan)

Smart Keys Three major uses Page navigation
FPL – Flight plan DB – Database Short-cut to change values on page (without pressing SEL and turning knobs) Clutter/de-clutter features on maps Three-way toggles for waypoints: show waypoint icon, show icon and label, and hide

Terminology: Waypoint
A specific named location either defined by the user or defined in the instrument’s database Database waypoints come in flavors: Airport VOR NDB Intersection (INT)

Terminology: Defining Different Directions
Desired Track / Course Bearing Track Heading Track Angle Error Note: All directions in GPS unit are magnetic

Desired Track TO Waypoint FROM Waypoint
North (magnetic) TO Waypoint Course DTK FROM Waypoint DTK – Desired Track: course direction, direction between two waypoints

Bearing TO Waypoint FROM Waypoint
North (magnetic) TO Waypoint BRG FROM Waypoint BRG – Bearing: direction to a waypoint

Heading TO Waypoint FROM Waypoint
North (magnetic) TO Waypoint FROM Waypoint Heading Heading – direction the aircraft is pointed

Track TO Waypoint FROM Waypoint
North (magnetic) TO Waypoint TRK FROM Waypoint TRK – Track: direction the aircraft is going

Track Angle Error TO Waypoint FROM Waypoint
North (magnetic) TO Waypoint Course DTK DTK TRK TAE FROM Waypoint TAE – Track Angle Error: difference between track and desired track

Recap – Defining Different Directions
North (magnetic) TO Waypoint Course BRG DTK TRK TAE FROM Waypoint Heading DTK – Desired Track: course direction, direction between two waypoints BRG – Bearing: direction to a waypoint TRK – Track: direction the aircraft is going Heading – direction the aircraft is pointed TAE – Track Angle Error: difference between track and desired track

A Tour of Display Pages How to Read Displayed Information
NAV ETE Split Screen Map Full Screen Map More Pages

Reading the NAV ETE Display
Estimated Time Remaining Value (26 minutes) TO-Waypoint Identifier (Airport DLH, Duluth) “Estimated Time Enroute” Label Graphic Course Deviation Indicator (CDI) Triangle at center is TO/FROM indicator (pointing up indicates “To”) CDI “needle” is at the end of bar graph line (indicates we need to go right to get back on course) Distance off-track (0.17 NM left of course) Bearing to the TO-waypoint (017 degrees) Distance to the TO-waypoint (43.5 nautical miles)

Diamond indicates additional pages of information can be selected by turning the small knob Relative Bearing Indicator arrow points to approximate bearing relative to current track – It points in one of 8 directions

Some ‘Diamond’ NAV ETE Pages (Use small knob to move between)

Differences when past “TO waypoint” Estimated return time to the “TO-waypoint” (13 minutes) Increasing if moving away; estimated based on current ground speed Graphic CDI center triangle points down to indicate “FROM” – i.e. past the “TO-waypoint” FROM Waypoint TO Waypoint TO-side of destination waypoint FROM-side of destination waypoint

ETE Display Course Deviation Indicator
CDI Sensitivity 0.3 nm Full deflection, 0.3 nm Each dot, 0.01 nm Each tick, 0.04 nm CDI Sensitivity 1.0 nm Full deflection, 1.0 nm Each dot, 0.05 nm Each tick, 0.14 nm CDI Sensitivity 5.0 nm Full deflection, 5.0 nm Each dot, 0.24 nm Each tick, 0.71 nm

Reading the Split Screen Map Page
To-Waypoint Identifier (Airport DLH, Duluth) Ground speed (100 Knots) Map scale (15 NM measured from top to bottom) Current track direction (014 degrees)

Remaining distance to the TO waypoint (114 Nautical Miles) Bearing to the TO Waypoint from current position (014 degrees) Course-deviation indicator (exactly on-course or slightly left of course)

Route-line (note map-orientation is currently North-up) Aircraft current position on map

Reading the Full Screen Map Page
Bearing to the TO Waypoint from current position (017 degrees) TO Waypoint Identifier (Airport DLH, Duluth) Remaining distance to the TO waypoint (75.0 Nautical Miles) Map scale (30 NM measured from top to bottom)

Reading the Full Screen Map Page
Route-line (note map-orientation is currently North-up) Waypoint Location Aircraft current position on map Waypoint Identifier

Map Clutter/De-clutter Smart Keys
Smart keys on maps are used primarily for clutter/de-clutter control For each kind of waypoint, there is a three-way toggle Display icon with label Display icon without label Don’t display Annunciators above keys indicate current state of each option FBL (Faribault) Airport icon shown and labeled APT (airport) annunciator fully lit, so airports will be shown and labeled

Smart keys on maps are used primarily for clutter/de-clutter control For each kind of waypoint, there is a three-way toggle Display icon with label Display icon without label Don’t display Annunciators above keys indicate current state of each option Halfway VOR (icon only) VOR annunciator half-lit, so VORs will be depicted as unlabeled icons.

Smart keys on maps are used primarily for clutter/de-clutter control For each kind of waypoint, there is a three-way toggle Display icon with label Display icon without label Don’t display Annunciators above keys indicate current state of each option INT annunciator unlit, so intersections will not be depicted

“1” indicates that this is the first set of smart keys for this screen
Numbered Smart Keys An annunciator which is a number indicates that there are more smart keys that can be used for the current screen Press the numbered smart key to get another set of smart keys “1” indicates that this is the first set of smart keys for this screen

More Pages Lets now look at the pages that we can get to after pressing each of the four page-selection hard keys NAV Pages MAP Pages NRST Pages INFO Pages

NAV Key Pages Select with Large Knob After Pressing NAV
ETA & BRG Also shows distance RAIM Prediction Altitude Assist Parallel Track Useful for offset route search GPS Position Basic Lat. & Long. Countdown Timer Arc Assist To/Next Wpt (Distance) To/Next Wpt (ETE) To/Next Wpt (ETA) From/To/Next Waypoint

MAP Key Pages Select with Large Knob After Pressing MAP
Split Screen Map – Map Plus Nav Info Full Screen Map Search and Rescue Map [if configured under Map Setup] Map Setup Several sub-screens can be selected using the small knob

NRST Key Pages Select with Large Knob After Pressing NRST
Airport (ARPT) VOR NDB INT User WPT Search Around WPT Runway Limits SUA (special use airspace) For each kind of waypoint, select which of the 20 nearest instances using the small knob

INFO Key Pages Select with Large Knob After Pressing INFO
Identifier, Type, and Name Radial and distance Bearing and distance Map Frequencies Approaches Lat/Long Sunrise/Sunset WPT comment

Review… What information can you get from this page?

Review – Here are a Couple Other Views (taken shortly afterwards)

Part 3 – Basic tasks with the GX-55
Select a waypoint and go direct to it View current Lat & Long Go directly to the nearest airport Enter a user waypoint Set up SAR functions View a SAR Map Remember a Current Position Creating & Activating a Flight Plan Useful Tricks Common Problems

Select a waypoint and go direct to it
Press the Direct-To Key ( ) Type of waypoint is flashing (i.e. has cursor); use small knob to select type of waypoint Use large knob to move cursor to first character of waypoint identifier Use small knob to change character Repeat using large knob to move cursor and small knob to change character and form the name of the destination waypoint. Press Enter Key D

Select a waypoint and go direct to it
Press the Direct-To Key ( ) Type of waypoint is flashing (i.e. has cursor); use small knob to select type of waypoint Use large knob to move cursor to first character of waypoint identifier Use small knob to change character Repeat using large knob to move cursor and small knob to change character and form the name of the destination waypoint. Press ENTER Key D

View Current Lat & Long Press NAV key
Turn large knob until ‘GPS Position’ screen appears

Go Directly to the Nearest Airport
Press the NRST key A page will display the closest airport Press the Direct-to Key ( ) The waypoint selection screen will appear with a flashing cursor Leave all information unchanged Press ENTER D

Enter a user waypoint (by Lat & Long)
Press NAV Key Press DB Smart Key Turn large knob until ‘Create User Wpt by Lat/Lon’ screen appears Press ENTER Use large & small knobs to enter a name for the new waypoint; also use knobs to enter lat & long Press ENTER to finish

Set up SAR Functions Part 1: Turn Map On
Press MAP Turn large knob until setup (Route Line) screen appears Turn small knob until SAR MAP ON/OFF screen appears If SAR MAP is off, press the SAR Smart key to turn it on

Set up SAR Functions Part 2: Select Sectional Chart
(SAR MAP ON/OFF Screen) Method 1- Press SEL (cursor will appear as flashing item) turn Large Knob until Position setting flashes turn the Small Knob until the desired sectional map name (MSP, for example) appears Press ENTER Method 2- Press POS smart key until MSP appears

View a SAR Map Press MAP Turn large knob until SAR Map appears
You will see Smart keys labeled GRD, MRK, and PAT Press GRD smart key and zoom scale using small knob to see grid lines Press GRD smart key to see grid number Press GRD2 smart key to see quarter grids

Remember a Current Position
(from SAR Map Page) Press MRK Smart key Use knobs to select name Press ENTER

Creating a New Flight Plan Part 1: Create and Name the Plan
Press FPL (if not available, press NAV first) Turn Large knob until ‘Create New Flight Plan’ Page appears Press SEL Use Large & Small knobs to enter the flight plan name Press ENTER when the name is complete

Creating a New Flight Plan Part 2: Begin Editing First Leg
Turn the Small knob to start inserting waypoints Press SEL

Creating a New Flight Plan Part 3: Enter Origin
At the INS? Prompt, press ENTER Use Large & Small Knobs to select waypoint and press ENTER

Creating a New Flight Plan Part 4: Enter Leg Destination
At the INS? Prompt, press ENTER Use Large & Small Knobs to select waypoint and press ENTER

Creating a New Flight Plan Part 5: Edit Another Leg or End Flight Plan
At the INS? Prompt, either… press ENTER to begin editing another leg or Press SEL to end the Flight Plan

Activating a Flight Plan
Press FPL (if not available, press NAV first) Turn the Large Knob until your flight plan appears (look for it by name) Press SEL Press ENTER

Other Flight Plan Actions
Press FPL (if not available, press NAV first) Turn the Large Knob until your flight plan appears (look for it by name) Press SEL Turn the Small knob to see other actions possible (examples: Reverse, Delete)

Useful Tricks Pressing a hard key one time, when viewing a page under another key, returns you to the last page viewed under the key pressed Useful for when you want to flip back-and-forth between a MAP page and a NAV page Pressing a hard key twice sends you to the default page for that key Pressing NAV two times will send you to the ETE NAV page Pressing MAP two times will send you to the split-screen map page

Common Problems “Autonav” mode displays a series of NAV pages, rotated in sequence – this can be very annoying if entered inadvertently Turn on by pressing ENTER while viewing a NAV page Turn off by pressing any key or turning any knob Remember to set up correct sectional chart when using SAR map

Review – What Page is This
It is the SAR Map Page

Review… How does one get from the NAV ETE page to the split-screen map page? Two Ways: Press MAP and turn the large knob until the split-screen map page appears Or Press MAP twice

Review… What information can you get from this page?

Part 4 – GX-55 Search patterns
Describing the patterns Parallel Line (Grid) Creeping Line Expanding Square Route and offset route Programming patterns into the GPS Flying to the pattern entry

Parallel Line Search Pattern a.k.a. “Grid Search”
“US Grids” are areas 15 minute to a side, serially numbered for each sectional chart (MSP means “Twin Cities” sectional) 7.5 minute quarter grids are named A, B, C, and D – in reading order, left to right, top to bottom ’ W o ’ W ’ N ’ N ’ ’ 414 445 446 MSP 413 A B C D A

Parallel Line Search Pattern a.k.a. “Grid Search”
The GPS unit labels the four corners (and also four search pattern entry points) 1, 2, 3, and 4 – clockwise starting in northwest. ’ W o ’ W ’ N ’ N 1 2 MSP 413 A 4 3

Describing a Parallel Line Pattern
Grid identifier and starting waypoint (i.e. corner of quarter-grid) Track spacing Direction of tracks – either E/W or N/S Note: Search area for a parallel line pattern in the GX55 is always a quarter-grid

Parallel Line Pattern Example
Quarter Grid MSP 413A1 Northwest corner of grid MSP 413A Track spacing 1 NM Tracks running east to west MSP 413 A Track spacing

Creeping Line Search Pattern
Shaped much like a parallel line pattern, but with legs aligned perpendicular to a route (rather than by ordinal directions) Descriptive parts: Starting point (any waypoint) Direction Starting left or right side Track spacing Leg length Number of legs Direction Track spacing Leg length Starting Waypoint Starting on left side

Expanding Square Descriptive parts
Starting waypoint (at center of pattern) Initial direction Track spacing Number of legs 3s s s 2s s 2s 3s Initial Direction

Offset Track Line Search a.k.a. Route Search
For a returning route search, 2 passes are made, each ½ track spacing offset from base course A non-returning route search will have a leg on the base course TO Waypoint Base Course FROM Waypoint

Offset Track Line Search a.k.a. Route Search
For the purpose of using the GPS, we will describe only one leg at a time A route leg will either be… On the course line (in which case a simple flight plan will suffice) Offset from the course line Described as a distance offset and a direction offset (either right or left of course)

Programming Patterns into GPS
Track-line/route searches accomplished using Flight plans and the “Parallel Track” setup page under NAV. Programming for parallel line, creeping line, and expanding square searches is begun by pressing the PAT smart key while viewing the SAR map page.

Programming the Parallel Line (i.e. Grid) Search Pattern
Prerequisite: The correct grid type (US Grid) and Sectional must be configured in the under map setup. MAP Press MAP to view map pages Turn large knob to view SAR map page Press the PAT smart key If needed, turn the small knob to view the “Parallel Line Search Page” Press ENTER to begin PAT ENTER

Programming the Parallel Line (i.e. Grid) Search Pattern
Press SEL to make cursor appear so that values can be edited Enter grid corner name, spacing, and track direction – use large knob to move cursor and small knob to change values Press ENTER to accept values Press ENTER again to activate the search pattern Press PAT to cancel search pattern SEL ENTER ENTER PAT

Programming the Creeping Line Search Pattern
Remember that direction entered is MAGNETIC (i.e. based on the magnetic variation information that the GPS unit has for the area) Note that GPS doesn’t provide means to enter a stopping condition (i.e. number of legs); it just keeps on going… You will need to choose a way to identify the end of the search pattern; perhaps by watching latitude and longitude

Press MAP to view map pages Turn large knob to view SAR map page Press the PAT smart key Turn the small knob to view the “Creeping Line Search Page” Press ENTER to begin MAP PAT ENTER

SEL Press SEL to make cursor appear so that values can be edited. You will see the cursor flash “Ins?” – it is asking whether you wish to insert a waypoint as the starting position for the search. Press ENTER to indicate “yes”. Enter waypoint information – use large knob to move cursor and small knob to change values Press ENTER to accept waypoint ENTER ENTER

You will now be back at the creeping line value page with the starting waypoint selected; enter the spacing and direction for the search – use the large knob to move the cursor and the small knob to change values Press ENTER to accept values A diamond appears on the page indicating that there is additional information that can be reached by turning the small knob. (While we had a cursor flashing we could not get to that other page because the small knob has a different job when we have a cursor.) ENTER

Turn the small knob to see the second page of creeping line pattern values Press SEL to make a cursor appear so that values can be edited Enter leg length and starting direction (left or right) – use large knob to move cursor and small knob to change values Press ENTER to accept values Press ENTER again to activate the search pattern Press PAT to cancel search pattern SEL ENTER ENTER PAT

Flying to Pattern Entry
Problem: The GPS unit sets up search patterns as temporary flight plans; it recognizes if you have already “passed” a waypoint and immediately advances to the next one This means that if you program the pattern while at the wrong end of the pattern, it will jump ahead to the nearest waypoint to you – and you will not be guided to a correct entry into the pattern, and some legs will be skipped.

Solution: Make sure the starting waypoint is the closest waypoint to you when to finish entering the search pattern program into the GPS For parallel line (grid) searches, be sure to program the GPS while outside the entry-corner of the grid

Enter program for search pattern here; Starting waypoint is closest Do not program search pattern here; several legs will get skipped

For creeping line searches, program the GPS outside the search area, on the centerline, just outside the starting waypoint

Direction Do not program search pattern here; several legs will get skipped Starting Waypoint Enter program for search pattern here; Starting waypoint is closest

For expanding square searches, begin programming the GPS near the starting waypoint; delay finishing the programming until arriving at the starting waypoint

Some Tasks We Haven’t Covered That You Should Know for SAR/HS/DR
Entering User Waypoints into the Database Using US Grid identifiers Programming and using parallel track offsets Consult the GX-55 “shorthand guide” for further information

Part 5 – Safety Issues User-interface tunnel vision
Over-reliance on GPS can be a trap IFR usage issues Other concerns

User-Interface Tunnel Vision
The GPS user interfaces are complex and draw your attention into the box and away from the business of flying the airplane Some operations involve several steps and quite a bit of thinking even if you are an expert using the device Maintaining “situational awareness” is extra-challenging Division of attention is critical Traffic, terrain, and obstructions* Altitude and heading* * Especially at search-altitude Another pilot or a well-trained crew member can be a big help!

User-Interface Tunnel Vision
Remember your priorities: Aviate Navigate Communicate Operating the GPS is secondary to flying the airplane Note: The airplane flies because of Bernoulli, not Marconi!

Over-reliance Trap Don’t be one transistor away from being lost
Use in conjunction with current charts and maintain navigational situation awareness Safe altitude (terrain and obstructions) Restricted and Prohibited Airspace and TFRs Class B, C, and D airspace Wildlife management areas Airports (and CTAF frequencies) MOAs and MTRs

IFR Usage Issues Not all GPS units are approved for IFR
Must be IFR approved equipment Must be permanent IFR-approved installation Some GPS units are approved for IFR en route only But they cannot be used as the sole means of navigation All Minnesota Wing aircraft GX-55 GPS units are placarded “VFR Only” Should maintain current database subscription ($) Don’t underestimate the need for training IFR usage is complex and outside the scope of this course Each GPS device has its own unique user interface Some sources suggest at least 40 hours of GPS training before using GPS approaches under IFR

Other Concerns Errors easy when entering waypoint data
Airport and VOR waypoints often have same identifier even when not co-located (example: AXN) Waypoints and stations that are near each other may not be exactly co-located (example MSP)

Other concerns GPS can be subject to accidental and intentional interference Easily jammed using strategically placed low-power transmitters WAAS is also at risk Selective Availability (SA) or SCATANA could be instituted during a national emergency (but this is unlikely) Current plan calls for possible use of “Selective Denial” where GPS is degraded or denied to specific geographic areas

Part 6 – Using the GX-55 Simulator
Tips for getting started Bugs and limitations How to find the simulator and more information

The GX-55 Simulator: Tips for Getting Started
The first time you run the simulator, you may be surprised at your initial location, off the coast of Africa at 0 degrees latitude, 0 degrees longitude! To put yourself someplace more familiar, enter any flight plan and you will be whisked away (at warp speed) to the first waypoint of your flight plan

Before “turning on” the simulator, don’t forget to enable “SAR” using the application’s “Options” menu This is analogous to the avionics shop enabling the SAR features on the real device

“Turn-on” the simulator by clicking the “on-off” button pictured in the simulator window To press GPS buttons, click on them with your mouse To turn GPS knobs, point at the knob with your mouse, and then right-click to turn the knob clockwise and left-click to turn counter-clockwise. Aim carefully; the large knob and the small knob are very close to each other

The GX-55 Simulator: Bugs and Limitations
It is not possible to practice following a course The simulator never allows you to go off-course and observe a CDI deflection Enter any flight plan or search pattern and it will send you immediately to the first waypoint The simulator will then follow the flight plan perfectly There is no way to practice arrival into a search pattern

The GX-55 Simulator: Bugs and Limitations
Unlike the real device, the simulator is doesn’t care where you are when you program a search pattern The real device, when performing a multi-leg flight plan or search pattern, gives you turning-arc lines The simulator doesn’t, but instead gives instantaneous [warp speed] pivots at each waypoint The implementation of the creeping line search is completely wrong in the simulator The user interface isn’t even the same as in the real device

How to Find the Simulator and More Information
GX-55 documentation and simulator Other resources The Minnesota Wing CAP GX-55 “shorthand guide” General information about GPS GPS Safety information Detailed information

GPS Navigation Using the Apollo GX-55

Similar presentations

Presentation on theme: "GPS Navigation Using the Apollo GX-55"— Presentation transcript:

Similar presentations

About project

Feedback

Log in

Auth with social network:

GPS Navigation Using the Apollo GX-55

Similar presentations

Presentation on theme: "GPS Navigation Using the Apollo GX-55"— Presentation transcript:

Similar presentations

About project

Feedback