GPS Navigation Using the Apollo GX-55 U.S. AIR FORCE AUXILIARY U.S. AIR FORCE AUXILIARY Lt. Col. Stan Kegel Minnesota Wing April 2009

GPS NavigationGPS NavigationUsing the Apollo GX-55Using the Apollo GX-55

U.S. AIR FORCE AUXILIARY

U.S. AIR FORCE AUXILIARY

Lt. Col. Stan KegelMinnesota Wing April 2009

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-55Course 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– 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)

19.2-19.7 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 LocationsA 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:

1. One can use seconds (of which there are 60 in one minute)

2. 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 LocationsCAP Standard Method

The standard we will use in CAP is degrees and decimal minutes

– Example: 45 degrees 35.4 minutes North93 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 LocationsCommunicating 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 LocationsYet 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

“Smart” Keys& “annunciators”

“Hard” keys

“Small”Knob

“Large”Knob

Large & Small Knobs

Moving between pages– 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

FROM Waypoint

TO Waypoint

Course

North (magnetic)

DTK

DTK – Desired Track: course direction, direction between two waypoints

Bearing

FROM Waypoint

TO WaypointNorth (magnetic)

BRG

BRG – Bearing: direction to a waypoint

Heading

FROM Waypoint


Heading

Heading – direction the aircraft is pointed

Track

FROM Waypoint


TRK

TRK – Track: direction the aircraft is going

Track Angle Error

FROM Waypoint

TO Waypoint

Course

North (magnetic)

DTK

TRK TAE

TAE – Track Angle Error: difference between track and desired track

DTK

Recap – Defining Different Directions

FROM Waypoint

TO Waypoint

Course

North (magnetic)

DTK

TRK

Heading

BRG

TAE

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 PagesHow to Read Displayed Information

NAV ETE Split Screen Map Full Screen Map More Pages

Reading the NAV ETE Display

TO-Waypoint Identifier (Airport DLH, Duluth)

“Estimated Time Enroute” Label

Estimated Time Remaining Value (26 minutes)

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)

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)


Relative Bearing Indicator arrow points to approximate bearing

relative to current track – It points in one of 8 directions

Diamond indicates additional pages of

information can be selected by turning the small knob

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


Differences when past “TO waypoint”

FROMWaypoint

TOWaypoint

TO-side of destination

waypoint

FROM-side of destination waypoint

Estimated return time to the “TO-waypoint” (13 minutes) Increasing if moving away; estimated based on current

ground speedGraphic CDI

center triangle points down to

indicate “FROM”

– i.e. past the “TO-waypoint”

ETE DisplayCourse Deviation Indicator

CDI Sensitivity 0.3 nm Full deflection, 0.3 nm Each dot, 0.01 nm Each tick, 0.04 nm



Reading the Split Screen Map Page

To-Waypoint Identifier (Airport DLH, Duluth)

Ground speed(100 Knots)

Current track direction (014 degrees)

Map scale(15 NM measured from top to bottom)


Remaining distance to the TO waypoint

(114 Nautical Miles)

Course-deviation indicator(exactly on-course or slightly left of course)

Bearing to the TO Waypoint from current position (014 degrees)


Route-line(note map-orientation is currently North-up)

Aircraft current position on map

Reading the Full Screen Map Page

TO Waypoint Identifier (Airport DLH, Duluth)

Bearing to the TO Waypoint from current position (017 degrees)

Map scale(30 NM measured from top to bottom)

Remaining distance to the TO waypoint

(75.0 Nautical Miles)

Reading the Full Screen Map Page

Route-line(note map-orientation is currently North-up)

Aircraft current position on mapWaypoint Identifier

Waypoint Location

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

APT (airport) annunciator fully lit, so airports will be shown and labeled

FBL (Faribault) Airport icon shown and labeled







VOR annunciator half-lit, so VORs will be depicted as unlabeled

icons.

Halfway VOR(icon only)







INT annunciator unlit, so intersections will not be depicted

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 PagesSelect 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 PagesSelect 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 PagesSelect 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 PagesSelect 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 theDirect-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







Press Enter Key

D







Press Enter Key

D







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 FunctionsPart 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 FunctionsPart 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 PlanPart 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 PlanPart 2: Begin Editing First Leg

Turn the Small knob to start inserting waypoints

Press SEL

Creating a New Flight PlanPart 3: Enter Origin

At the INS? Prompt, press ENTER

Use Large & Small Knobs to select waypoint and press ENTER

Creating a New Flight PlanPart 4: Enter Leg Destination

At the INS? Prompt, press ENTER

Use Large & Small Knobs to select waypoint and press ENTER

Creating a New Flight PlanPart 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


Turn the Large Knob until your flight plan appears (look for it by name)

Press SEL Press ENTER

Other Flight Plan Actions


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 Patterna.k.a. “Grid Search” (US Grid)

“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

94 00’ W 93 30’ W

45 30’ N

46 00’ N

93 45’

45 45’

414

445 446

MSP413 A

B

C D

A

Parallel Line Search Patterna.k.a. “Grid Search” (US Grid)

The GPS unit labels the four corners (and also four search pattern entry points) 1, 2, 3, and 4 – clockwiseclockwise starting in northwest.

94 00’ W o 93 52.5’ W o

45 52.5’ No

46 00’ No

MSP413 A

1 2

4 3

The “Other” Grid System – BASIC Grids

“BASIC Grids” are areas 1 degree to a side

– The first two digits are the latitude of the SE corner

– The remaining digits are the longitude of the SE corner

– A slash or dash is often used to separate the latitude digits and longitude digits

30 minute quarter grids [or quadrants] are named A, B, C, and D – in reading order, left to right, top to bottom

15 minute sixteenth grids [or sub-quadrants] are named within each quarter grid A, B, C, and D. The full name of the sixteenth grid with a SE corner at 46 N 93 W would be “4693DD”.

94 00’ W 93 00’ W

46 00’ N

47 00’ N

93 30’

46 30’

46/93B

46/93C 46/93D

46/93AB

46/93AC

46/93AD

46/93AA

Parallel Line Search Patterna.k.a. “Grid Search” (BASIC Grid)

The GPS unit labels the four corners (and also four search pattern entry points) 1, 2, 3, and 4 – clockwiseclockwise starting in northwest.

94 00’ W o 93 45’ W o

46 45’ No

47 00’ No

46/93AA

1 2

4 3

Comparing the two grid systems

Note that a BASIC sixteenth grid (or sub-quadrant) is the same size as a whole US Grid

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: The search area for a parallel line pattern in the GX55 is always a quarter-gridquarter-grid when using US Grids. (It is either a quarter-grid or sixteenth-grid when using BASIC Grids.)

Parallel Line Pattern Example

Quarter Grid MSP 413A1

• Northwest corner of grid MSP 413A

Track spacing 1 NM

Tracks running east to west

Track spacing

MSP413 A

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

Starting on left side

Leg length

Track spacing

Starting Waypoint

Expanding Square

Descriptive parts– Starting waypoint (at

center of pattern)– Initial direction– Track spacing– Number of legs

Initial Direction

s2s

2s3s

s

3ss

Offset Track Line Searcha.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

FROM Waypoint

Base Course

Offset Track Line Searcha.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 under map setup.

PAT

MAP

ENTER

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

Programming the Parallel Line(i.e. Grid) Search Pattern

SEL

ENTER

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

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

Programming the Creeping LineSearch Pattern

PAT

MAP

ENTER




Turn the small knob to view the “Creeping Line Search Page”



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

SEL

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


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


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




SEL

ENTER

PAT

Setting up for the “Other” Grid System – BASIC Grids

First, go to the SAR map set-up page, and press the GRD smart key to change the grid type to BASIC.

Also, make sure the Position field is set to NW (as in North latitude, West longitude). Press the POS smart key to change this value.

GRD

POS

Setting up for the “Other” Grid System – BASIC Grids

Next, while still viewing a map set-up page, turn the small knob to get the SAR Position Page*.

Press the SEL button to get a cursor so values can be changed**.

Use the large knob to move the cursor and the small knob to change values. Change the Latitude and Longitude to represent the correct 10 degree by 10 degree area (i.e. less than and within 10 degrees of the area to be searched).

Press Enter to accept the new values.ENTER

SEL* Note: This page is only reachable when the grid type is set to BASIC.

Programming the Parallel Line Search Pattern for the “Other” Grid System

Prerequisite: The intended grid type (BASIC Grid), hemispheres (“NW”), and SAR Position (SE corner of the 10 degree by 10 degree area) must be configured under map setup.

PAT

MAP

ENTER




If needed, turn the small knob to view the “Parallel Line Search Page”


Programming the Parallel Line Search Pattern for the “Other” Grid System

SEL

ENTER

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




ENTER

PAT

* The grid number entered here is the last digit of the latitude followed by the last digit of the longitude of the SE corner. For example, to specify grid 46/93AA, with entry at the NE corner (i.e. corner “2”), first set the SAR Position in Map Setup to Lat. 40, Lon. 90, then on this page enter grid “63AA2” [as shown above]. Note that, in the case of BASIC grids, either a quarter grid (30’ x 30’), with one letter, or a sixteenth grid (15’ x 15’), with two letters, can be specified.

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

Starting Waypoint

Enter program for search pattern here; Starting waypoint is

closest

Do not program search pattern here; several legs will get

skipped


– 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 CoveredThat 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:1. Aviate

2. Navigate

3. 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 simulatorhttp://www.garmin.com/products/gx55/http://www8.garmin.com/include/gxsimulator/SimulatorPopupGX.html

Other resources– The Minnesota Wing CAP GX-55 “shorthand guide”

http://www.mncap.org/es/reference_aircrew.cfm– General information about GPS

http://www.garmin.com/aboutGPS/– GPS Safety information

http://www.aopa.org/asf/publications/sa01.pdf– Detailed information

http://www.navcen.uscg.gov/gps/geninfo/

Documents

GPS Navigation Using the Apollo GX-55 U.S. AIR FORCE AUXILIARY U.S. AIR FORCE AUXILIARY Lt. Col. Stan Kegel Minnesota Wing April 2009