Magellan
GPS Satellite
Navigator
Reference Guide
Welcome from the Magellan crew.
With the purchase of a Magellan GPS satellite receiver, you have joined the
thousands of people who enjoy using GPS in their professional and recre-
ational activities.
Since we introduced our first product more than five years ago, Magellan has
established a reputation for product excellence and customer support. Our
customers include sailors, commercial fishermen, pilots, geologists, explorers, surveyors, and the Allied Forces in Desert Storm. Your receiver represents
the next generation of GPS technology — technology that is combined with
our hallmark durability and ease of use, which have evolved over years of field
experience.
With your receiver are two documents: the
Reference Guide
and the
Field
Guide.
Like the Magellan GPS receiver, the
Field Guide
is tough and ready
to go where ever your adventures take you. Printed on waterproof
"paper", its purpose is to explain how to operate the receiver — in
any weather. When not in use, the
Field Guide
fits neatly in the
carrying case that is provided with the receiver.
The
Reference Guide,
which you are reading now, provides Background information that will give you a deeper technical appreciation of the receiver and the GPS technology in general.
Where ever your outdoor recreation excursions take you, we hope your
Magellan receiver will add to your fun and safety.
So that your experiences contribute to the next generation of Magellan
receivers, I need to hear from you. All comments will be considered for
incorporation into future products. Address your letters to me at Dept. 3-A.
Yours truly,
Randy D. Hoffman, President and CEO
Magellan Systems Corporation
Dept. 3-A
960 Overland Court
San Dimas, CA 91773
First-Time GPS Users
...........................
1
Navigation, 1; Latitude/Longitude, 1
;
Using
Position Fixes,
2; Navigating with Waypoints, 3; Setting
a Route, 5;
Navigating with a Route, 5; Entering
a Waypoint, 6; UTM
Coordinates, 6; Applications, 8.
General Usage
...........................
9
Power, 9; The Antenna, 10; Initialization, 11; Setup, 13;
The Auxiliary Functions, 17; Map Reading
, 19.
Tutorial
...................................
22
Waypoints, 23; Routes, 24; Reading
the Pointer Display,
26; Direct-To, 26; Backtrack, 28; MOB, 28; Entering
UTM
Coordinates, 29.
Global Positioning System
.......
30
What is GPS?, 30; How Does GPS Work?, 30; Accuracy,
31; More Information, 31.
Specifications
..........................
32
Technical Notes, 32; Packing
List, 33; Optional Accesso-
ries, 33.
Troubleshooting
......................
34
What to do when you're having problems.
USE GOOD JUDGEMENT
This product is an excellent navigation aid, but does not replace the need
for careful orienteering and good judgement. Never rely solely an one
device for navigating.
USE CARE
The Global Positioning System (GPS) is operated by the U.S. Government,
which is solely responsible for the accuracy and maintenance of GPS.
The accuracy of position fixes can be affected by the periodic adjustments
to GPS satellites made by the U.S. Government and is subject to change in
accordance with the Department of Defense civil GPS user policy and the
Federal Radionavigation Plan.
USE CAUTION
Accuracy can also be affected by poor satellite geometry. When the
accuracy warnings appear an the screen, use the data with extreme
caution.
USE PROPER ACCESSORIES
Use only Magellan cables and antennas; the use of non-Magellan cables
and antennas may severely degrade performance or damage the receiver,
and will void the warranty.
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First-Time GPS Users
This section is to help readers who are new to navigation or to electronic
navigation equipment. lt explains terms that are commonly used by navigators worldwide and some basic concepts of navigation, such as position fixes
and coordinates.
Navigation
Navigation is getting from one place to another. lt is also knowing where you
are in relation to the path between those locations. At its most basic,
navigation is getting from here to there and home again. At its most
advanced, navigation has been called both an art and a science.
In the past, people left markers — blazes cut into trees, sticks laid out in a
particular pattern, or even small piles of stones — to mark a location or to
show the correct path to an important position. Later, these paths were
charted. This eventually developed into the maps and charts we use today.
Today, markers can be made electronically with a GPS receiver, even at sites
that do not permit leaving physical marks, such as on a lake. You can mark
a path even in featureless terrain by making electronic blazes (called
waypoints) and storing them in the receiver's memory. These electronic
markers can be used to return to your starting position, and can be reused
again and again.
All you have to do to make full use of this wizardry is become familiar with
a few terms and what they mean.
Latitude and Longitude
A
position
is a location that can be
described in a unique, numerical
way. The format that is used to
describe a position is called a coordinate system. The most common
coordinate system in use today is
Latitude/Longitude (Lat/Lon).
Lat/Lon projects lines of latitude (parallels) and lines of longitude (meridians) onto the earth. Lines of latitude are the equator and the hori-
zontal lines that are "parallel" to it. Lines of longitude are the vertical lines
that are perpendicular to the equator and pass through the poles. A position
is described as the intersection of a line of latitude and a line of longitude.
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This is much like describing a position in a
city by the street intersection, but "Fifth and
Main" can describe
more than one location,
since these are commonly used designa-
tions. Lat/Lon uses
numbers and hemisphere to describe each
position in a unique
way. Using Lat/Lon co-
ordinates, no position
can be confused with
any other.
In Lat/Lon, positions are
described as being so
many degrees north or
south of the equator (up to the poles, which are 90°N and 90°S; the equator
is 0° latitude), and so many degrees east or west of the Prime Meridian, which
is 0° longitude. (The Prime Meridian passes through Greenwich, England.)
Parts of a degree are minutes; there are 60 minutes (written as 60') to a
degree. Minutes can also be divided into smaller units. Fractions of a minute
can be expressed as decimals or as seconds. (There are 60 seconds to one
minute written as 60"). So a Lat/Lon position coordinate can be expressed in
two ways, which your Magellan GPS receiver displays as 25°47.50 or
25°47'30.
The Magellan GPS receiver can also display coordinates in another common
coordinate system — UTM, or Universal Transverse Mercator. UTMs are
described at the end of this section.
Using Position Fixes to Record Your Movement
A
position fix
is the coordinates of a location as determined by your GPS
receiver, positioning with a map and compass, or some other orientation
technique. lt "fixes" your position to a specific place. If the fix is saved (either
by writing it down or by storing it in the receiver's memory), the fix becomes
a
waypoint.
The difference between a fix and a waypoint is that the waypoint
can be recalled for use at a later time.
Imagine that you are camping in the area illustrated on the next page. Before
setting out to explore the area, you determine the position of your camp
(latitude/longitude) by obtaining a position fix, which you store as waypoint
2
"CAMP." As you walk to your skiff at the dock, the receiver continues to
obtain position fixes; these are "updates" to the first fix obtained. Once at
the dock, you save the current position fix as waypoint "DOCK." Instead of
travelling directly across the lake to the inlet on the other side, you make a
detour to the buoy to avoid an area you know is too shallow for your craft.
Save the position fix at the buoy as waypoint "BUOY." You now continue to
the inlet, where you tie up your skiff and save another position fix as waypoint
"INLET."
The position fixes that are saved as waypoints (CAMP, DOCK, BUOY, and
INLET) can be used as electronic markers to record where you've been. These
waypoints can also be used to guide you back to your camp.
Navigating Home With Waypoints
When it's ti
me to return to your camp, you decide to establish your course
and navigate with the GPS receiver. Becoming familiar with the receiver now
may help you on a later trip if weather conditions (cloud cover, rain, etc.)
should make using your own navigation skills difficult, or if you need
navigation assistance in an emergency.
3
The first thing you have to do is to
return to your skiff, which you do
by getting a current position fix,
then setting a Direct-To course. A
Direct-To course is a straight line
from your current position to the
waypoint you select. Here, the
Direct-To course is to waypoint "INLET".
The Direct-To function will tell you
the distance and bearing from the
present position to INLET. Bearing
is the relative direction of the des-
tination with respect to north.
Distance is a great circle measurement, which means that it is the shortest
distance between two points along the curved surface of the earth. Measurements made on a map are rhumb line measurements, or the shortest distance
between two points on a flat
surface. When projected back to the globe, it
is apparent that the rhumb line measurement is both less direct and longer
than the great circle measurement, though the difference between the two
may be slight over short distances.
As you move toward INLET, you have both speed and direction of movement.
Speed is SOG, or speed over ground (sometimes referred to as groundspeed).
The direction you are
moving is your track, or
COG (course over
ground). In this example, COG is about
275°T. If you stay on
your intended course,
COG will be the same
as bearing to the intended destination.
Time to go (TTG) is based on the distance to the destination and how quickly
you are moving toward it.
4
If you stray off course while using the GPS receiver, the receiver will
indicate
the degree and direction of your error, and a steering correction.
(This is
described in more detail in
Navigating with a Route.)
Setting a Route with Stored Waypoints
To navigate safely from the inlet to the dock, you set a route from INLET to
BUOY, then to DOCK. A route is required to help you avoid the shallow area
or any rocks that you may not see when visibility is poor.
A route is a planned course from one place to another. lt is often divided into
shorter units, called legs.
Navigating with a Route
To be sure that you avoid shallow or rocky areas, you must stay on course.
Any time you stray from the courseline of the current leg, the Magellan GPS
receiver will display a cross track error, or XTE.
XTE is the distance between you and the courseline, measured as a perpendicular from the courseline to your current position. lt also indicates whether
you are to the right or left of the courseline. XTE does not include any variable
for the direction you or your craft are actually facing.
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The Magellan GPS receiver displays XTE graphically on a course deviation
indicator, or CDI. The CDI displays the courseline at the center of a scale, and
your current position relative to the courseline is shown as a symbol. When
you are to the left of the courseline, the symbol is to the left of the CDI's
center.
As you travel, the navigation displays will be updated with each position fix
update. You will always know where you are in relation to your destination
and courseline. When you get within 500 feet of the leg's destination, the
receiver will display "CLOSE" at the bottom of the screen. When you are
within 200 feet of the destination, "ARRIVED" is displayed.
If you are on a multileg route, the receiver will switch legs when you cross an
i
maginary line that is perpendicular to the courseline and bisects the
destination waypoint.
Entering a Waypoint
lt is not necessary to visit a place for its coordinates to be in the receiver's
memory. You can obtain coordinates from a friend or pick them up from a
map and key them into the receiver as a waypoint.
Please refer to
Tutorial
in this guide to key in a waypoint. Refer to
Reading
a Map
to get waypoint coordinates from a map.
UTM Coordinates
Another commonly used coordinate system is UTM (Universe Transverse
Mercator), which is generally
found on land-based maps and quad sheets
that are produced by government map providers. On land, you may find that
UTM coordinates are easier to use than Lat/Lon
.
UTM coordinates are easy to use, but since the model
it is based on is
somewhat abstract, this section is a very simplified introduction to UTM.
Instead of projecting an imaginary grid of intersecting lines onto the globe,
UTM projects sections of the globe onto a flat surface. Each of these sections
is called a "zone." There are 60 zones to cover the entire earth between 84°N
and 80°S (polar areas are not described by UTM). Each zone is 6°
wide as
projected from the earth's center.
6
A UTM position is described by three elements; the zone it is in, the easting,
and the northing. Eastings and northings measure how far into a zone a
position is in meters. Eastings are an east/west measurement, and correspond
roughly to longitude. Northings are a north/south measurement, and corre-
spond to latitude.
This chart shows Magellan's position described in both Lat/Lon and UTM
coordinates. Your GPS receiver can display coordinates in all of the manners
shown.
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APPLICATIONS
In addition to the use described in the preceding example, the Magellan GPS
receiver is ideally suited to a wide variety of outdoor activities, including:
Backpacking — you have the freedom to explore places that
are off the beaten path or snow-covered areas with the
security of knowing that you can easily return to the trail
with either the Direct-To or Backtrack
TM
features.
Cross Country Skiing — find your way in any weather
conditions, even if snow fall obscures your trail or in poor
visibility.
Hunting —scout a potential hunting area before the season
starts, and save promising locations or important landmarks
as waypoints. You will then be able to reach any of these
waypoints or return to base, even before dawn or in poor
weather.
Fishing (salt or fresh water) — save your favorite fishing
spots in the receiver's memory as waypoints, even when
fishing on a boat other than your own. Travel to or from
these waypoints even in fog.
Sailing and Boating — the portable receiver is ideal for use
in rental or vacation craft. The receiver includes an MOB
(man overboard) feature under the Direct-To function.
Gliding and Hang Gliding — navigate with greater safety
when cloud cover sets in or the weather changes suddenly.
Canoeing and Kayaking — enter hazards and portages as
waypoints to monitor how close you are to them. Note your
progress along the river in unfamiliar surroundings. Locate
rendezvous sites easily.
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POWER
The receiver is powered by three AA batteries. lt can also be powered from
an external DC power source by using the optional Magellan Power/Data
Cable.
Batteries.
We suggest using AA alkaline batteries to power the receiver.
(
Magellan Systems recommends Eveready Energizer
TM
batteries.) Alkaline
batteries will power the receiver for 5 hours or more of continuous operation.
To insert batteries,
remove the battery
tray as illustrated
and insert batteries
as indicated within
the battery tray.
When the battery
power level drops, a
warning message
will appear on all
displays
(LOW
BATT). The receiver
still has sufficient
power to operate for
up to 30 minutes if alkaline batteries are being used.
When the batteries no longer hold enough power to operate the receiver, the
receiver turns itself off. The batteries will still be able to maintain the memory
for a time, but the receiver can be operated only if external power is supplied
or if fresh batteries are installed.
lt is possible to use rechargeable batteries, but there are a couple of things
you should be aware of when using them. Commercially available NiCad
batteries typically have poor power performance after repeated use, and
rechargeable alkaline batteries maintain only 50% of the useful life of
standard alkaline batteries. Rechargeables also have a very sudden power
drop at the end of their charge. The drop may be so sudden that the battery
warning is not displayed, although memory can be maintained for a while.
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