Intro to Navigation

CHAPTER 1

INTRODUCTION TO NAVIGATION

• Locate their position

• Travel from one place to another

Navigation enables mariners to:

Terrestrial Sphere or Globe

A sphere on which is depicted a map

of the Earth (terrestrial globe)

North Pole

South PoleThe north and south poles are

located at the ends of the axis on

which Earth rotates.

Meridians

Lines running through the poles and

around the Earth are called meridians.

North Pole

South Pole

The great circle of the Earth that is

equidistant from the North Pole and

South Pole

(Cuts every meridian in half)

Equator

EQUATOR

60°

30°

0° 0°

60°

30°

60°

30°

60°

30°Northern Hemisphere

Southern Hemisphere

South Pole

North Pole

Eastern

Hemisphere

Western

Hemisphere

South Pole

North Pole

Northern

Hemisphere

Southern

Hemisphere

Half of a globe

Hemisphere

Meridians and the equator are called

great circles because they divide the

globe into two halves.

EQUATOR

S pole

N pole

LONGITUDE

W E

Greenwich

England

Any circle formed by the intersection

of a plane passing through the Earth’s

center, with the Earth’s surface

Great Circle

The equator is the only great circle

going around the globe from east to

west. The other lines are called parallels,

since they go around the globe parallel

to, and north and south of the equator.

ParallelsEquator

Prime

Meridian

One example

of a great circle

N

S

Greenwich meridian

(longitude 0°)

Equator

(latitude 0°)

A great circle is any circle whose

plane passes through the Earth’s

center, no matter what direction.

What is the significance of the

great circle in navigation?

What is the significance of the

great circle in navigation?

The shortest distance between

two points on the Earth lies along

the path of a great circle passing

through those two points.

Any unbroken part of the

circumference of a circle or

other curved line

Arc

The distance around a circular area

Circumference

What is the circumference of the Equator?

One example

of a great circle

N

S

Greenwich meridian

(longitude 0°)

Equator

(latitude 0°)

Center of

The Earth

360°360°

Regardless of the

size of the circle,

the circumference

has 360°.

1° = 60 minutes

1 minute = 60 seconds

360°

Measurement along a meridian

or parallel is expressed in terms

of degrees, minutes, and seconds

of arc (the curve of the circle).

0°

0°

The Greenwich meridian is numbered

0, or 0°, and is called the prime

meridian.

Greenwich Royal

Observatory

The meridian running through

Greenwich, England, from which

longitude east and west is measured

Prime Meridian

NORTH

POLE

INTERNATIONAL DATE LINE

PRIME MERIDIAN

International Date Line

180°

International

Date Line

Old Date

New Date

New Day

Old Day

Noon

Midnight

International

Date Line

0° Prime

Meridian

Equator

Western Hemisphere

Eastern

Hemisphere International

Date Line

Pacific

Ocean

Meridians (longitude lines) between the

prime meridian and 180th meridian are

numbered 0° to 180° east (E) or west (W).

Meridians

Prime

Meridian

0° Longitude

Measurement of position east or west

from the prime meridian

Longitude

The distance of arc east (E) or west (W)

of the prime meridian, measured along

a parallel

Longitude

Prime

Meridian

Greenwich

W E

Longitude Lines

Measurement of position north or

south of the equator

Latitude

Latitude

The distance of arc north (N) orsouth (S) of the equator, measuredalong a meridian

Grid system of latitude and longitude

lines

Latitude Longitude

Prime

meridian

Equator

LATITUDE LONGITUDEEARTH’S

GRID

90°90°

North

Latitude

South

Pole

North

Pole

West

Longitude

East

Longitude

Remember!

South

Latitude

• Latitude is always measured north

or south from 0° through 90°

• Longitude is always measured east

or west from 0° through 180°

New Orleans, LA

30N, 90W

Express latitude

and longitude in

degrees, minutes,

and seconds.

Washington, D.C.

38°58'52"N

latitude

77°01'12"W

longitude

Washington, D.C.

38°59'N latitude

77°01'W longitude

This is spoken

as thirty-eight

degrees,

fifty-nine

minutes north,

seventy-seven

degrees, one

minute west.

Washington, D.C.

38°58'52"N

latitude

77°01'12"W

longitude

Seconds are used

only if very exact

locations are

required.

One minute of arc measured along

the equator, or any other great

circle

Nautical Mile

6,865 Nautical Miles

6,888

Nautical Miles

Equatorial Diameter - 6,888 Nautical Miles

Polar Diameter - 6,865 Nautical Miles

Comparison of a Statute Mile

to a Nautical Mile

NAUTICAL MILE = 6,076 FEET OR 2,000 YARDS

STATUTE MILE = 5,280 FEET OR 1760 YARDS

0 500 1000 1500 2000

YARDS

Dividers

Distance on a chart is measured along

the meridian, using a tool called dividers.

Measuring Distance

30 Nautical

Miles

52 Nautical

Miles

60 Nautical

Miles

60°

30°

0°

P

Length of a Degree of Longitude at

Various Latitudes

Parallel

Distances are not

measured on

parallels of latitude,

because one minute

equals one nautical

mile only along the

equator.

Dividers

Remember!

1 knot = 1 nautical mile per hour

Origin of the term knot

An old sailing day’s log for measuring

the speed of a vessel

Chip Log

True Nautical Direction

Measured from true north (North Pole)

as located on a globe

32-point Compass

The four primary directions of the

compass; the north, south, east,

and west points

Cardinal Points

North, South, East, West:

the four primary directions

of the compass

Cardinal Directions

On the compass rose above, only north

is filled in. Fill in the rest of the points

on the compass, going clockwise, using

the standard abbreviations.

Express nautical directions in

three digits:

065° (Zero six five degrees)

090° (Zero nine zero degrees)

Course – Direction the ship is steered

through the water

Heading – Direction the ship is facing

MAGNETIC COMPASS

Magnetic compasses

give direction relative

to magnetic north.

GYROCOMPASS

Gyrocompasses

reference true

north.

Navigational compass containing agyroscope, that, when adjusted forlatitude and speed, shows true northor communicates this informationto one or more gyro repeaters.

Gyrocompass

TRUE

NORTH

MAGNETIC

NORTH

Magnetic Compass

A compass having a magnetized

needle generally in line with the

magnetic poles of the Earth

United States

Canada

NORTH

MAGNETIC

POLE

Magnetic compasses point to theEarth’s northernmost magnetic pole,located in northern Canada.

Difference between magnetic and true

north in degrees

Variation Angle

VariationNorth Pole

Remember, variation changesdepending on your position relativeto magnetic north.

How Variation Affects the Compass

Magnetic North

To convert from magnetic to true,

just add or subtract the variation

at your location to the magnetic

bearing.

Remember — Westerly variations

are subtracted, and easterly

variations are added.

Converting Direction

Example of Converting Direction

If your ship was heading 080° magneticin a region where the variation was10° East, what is the true heading?


If your ship was heading 080° magneticin a region where the variation was10° East, the true heading would be080° + 10°, or 090° true.

If your ship was heading 270° true in a

region where the variation was 10° East,

what is the magnetic heading?


If your ship was heading 270° true in a

region where the variation was 10° East,

the true heading would be 270° – 10°,

or 260° magnetic heading.


The direction of an object from an

observer, measured clockwise in one

of three standard ways:

• True bearing

• Magnetic bearing

• Relative bearing

Bearing

TN

True Bearing

090°TRUE

BEARING

Light

House

Bearing using true north as the

reference

True Bearing

Difference between true and magnetic bearing

TRUE NORTHMAGNETIC

NORTH

Light

House

The direction of an object measured

clockwise from magnetic north

Magnetic Bearing

TN

Relative Bearing

RELATIVEBEARING

030°

Light

House

The direction of an object measured

clockwise from the ship’s head (bow)

Relative Bearing

When recording a bearing, assume it tobe a true bearing unless followed by theletters M or R.

030°M means 30° right of magnetic north030°R means 30° off the starboard bow

Objects seen by lookouts are reported

in terms of relative bearing by degrees.

• Dead ahead, or bow – 000°R• Starboard beam – 090°R• Dead astern – 180°R• Port beam – 270°R

Relative Bearings

To emphasize that it is a true bearing,

the letter T (for example 030°T) follows

the three-digit true bearing, spoken

―030 degrees true.‖

True Bearing = Relative Bearing + True Heading

(Subtract 360° if sum is greater than 360°)

TN

090°

TRUE

BEARING

RELATIVE

BEARING

030°

Light

House

Type of map used to navigate on

water

Nautical Chart

A nautical

chart is a

standardized

drawing

representing

part of the

navigable

waters of the

Earth.

Nautical Chart

Science of measurement, description,and mapping of the Earth’s surface waters, with special reference to theiruse for navigation

Hydrography

• Water depths• Nature of bottom• Overhead obstructions• Navigation aids; buoys,lights, and anchorages

Hydrographic information given on a chart includes:

Globe

Impossible to

work navigation

problems or

chart courses

Chart

Necessary to

work navigation

problems

Makers of maps and charts who use

math to work out chart projection

techniques

Cartographers

It is necessary

to convert the

round surface of

the globe to one

that is flat and

two-dimensional

(having only

length and

width)—to

a flat piece of

paper on which a

chart is drawn.

Chart projections

Cyli

nd

rical

Merc

ato

rC

on

ical

Pers

pecti

ve C

on

icP

lan

ar

Ort

ho

gra

ph

ic

Flat surface representative of the

Earth

Chart Projection

Mercator Projection

The best-known map or chart projection

Earth is projected onto a

cylinder-shaped piece of paper,

wrapped around the globe at the

equator

Mercator Projection

• Commonly used for navigational charts

• Developed by a Dutch cartographer,

Geradus Mercator, in the 1500s

• Most useful projection for navigation

Mercator Projection

Geradus Mercator

A projection on which any rhumb line is shown as a straight line, used chiefly in navigation, though the scale varies with latitude and aerial size and the shape of large areas are greatly distorted

Conformal Projection

Great Circle

TrackRhumb Line

A curve on the surface of a sphere

that cuts all meridians at the same

angle; the path taken by a vessel or

aircraft that maintains a constant

compass direction

Rhumb Line

• Used to measure distance• Relationship between actualand chart distance

• Printed near the legend asa ratio, such as 1:7,500,000

SCALE 1:7,500,000

Scale of Charts

Small scales

are used to

depict large

areas on a

chart, and

large scales

are used to

depict small

areas.

If an inch on the chart represents 50 miles,

what would five inches represent?

Measuring distance on a chart

If an inch on the chart represents 50 miles,

what would five inches represent?

Measuring distance on a chart

250 Miles

Remember

• The larger the scale, the smaller the

area shown on a given chart or map.

• The large-scale charts show areas

in great detail.

• Features appearing on a large-scale

chart may not show up at all on a

small-scale chart of the same area.

Types of Charts

Harbor

Nautical Sailing

• Symbols, figures, and abbreviations• Depth of water• Type of bottom• Navigational aids

Nautical charts have information forsafe navigation, such as:

Harbor charts are large-scale charts thatshow harbors and their approaches in detail.

Coastal charts are intermediate-scale charts used to navigate a vessel whoseposition may be determined by landmarks and lights, buoys, orsoundingsoffshore.

The act of measuring the depth of an

area of water

Sounding

General ocean sailing charts aresmall-scalecharts showing theapproachesto large areas of the coast.


End of Part 1


Part 2

Depths of

water may

be given in

feet, fathoms,

or meters.

A unit of length equal to six feet

(1.8 meters); used chiefly in nautical

measurements

Fathom (of depth)

Plotting

Plotting

In order to use the nautical chart for

navigating, you must know something

about how courses, bearings, and

lines of position are plotted on it.

Parallel Rulers

A pair of straightedges connected by

two pivoted crosspieces of equal

length so as to be parallel at all times;

used for various navigational

purposes, especially for transferring

the bearing of a plotted course to a

compass rose

Parallel Rulers

Protractor

An instrument having a graduated arc

for plotting or measuring angles

Three-Arm

Protractor

Parallel Motion

Protractor (PMP)

Measuring

Distance on a

Mercator Chart

Accurate position determined without

use of any previous position, using

visual, electronic, or celestial

observation

Fix (position)

A line indicating

a series of possible

positions of a ship

as a result of

observation or

measurement

Line of Position

(LOP)

Lines of Position

SPIRE

CAPE

RANGE BEARING

TANGENT

DISTANCE ARC

Lines corresponding to the bearings

are plotted on the chart. They are

labeled with the 4-digit time of

observation above the line.

Bearing Lines of Position

Two landmarks or navigation aids are

observed in line, one behind the other

Visual Range

Visual RangeRear Marker

Front Marker

Rear

Marker

Front

Marker

A circular line of position

Distance Arc

Devices used to

measure distance

to a landmark

Radar Stadimeter

Sextant

Optical distance-measuring device

that measures angles to determine

distance to an object using as a

reference the distance to an object of

known height

Stadimeter

Stadimeter

An astronomical instrument used to

determine latitude and longitude at

sea by measuring angular distances,

especially the altitudes of Sun, Moon,

and stars

Sextant

Sextant

Most commonly used

Obtain a fix with these combinations

of lines of position:

• Two or more lines of bearing

• A distance arc and a line of bearing

• Two or more distance arcs

• A visual range and a distance arc

• A visual range and a line of bearing

• Two simultaneous visual ranges

A fix from two

crossed bearings

TOWER

1545

A fix by a

bearing and

distance from

the same object

1314

DOUBLE POINTLIGHT

A fix from three

intersecting

bearings

SMITH

POINT

HALL REEF LIGHT

JONES

BLUFF

A fix from two

visual ranges

LIGHT

X

LIGHT

W

LIGHT

W2152

Visual Fix

Electronic/Celestial Fix

Dead Reckoning Position

Estimated Position

Plotting Symbols

1300 FIX

1245 FIX

TOWER

Marking Ship’s Fix

FACTORY

LIGHTHOUSE

The determination

of position by

visual means

Piloting

Piloting

The determination of the course or

position of a ship or airplane by any

of various navigational methods or

devices

Fathometer

Stadimeter

Radar

BuoyLighthouse

CompassNavigation Aids

Bearing Circle

Chart

Sonic device used to measure water

depth

Echo sounder (Fathometer)

Fathometer

Echo Sounder

SONAR (S0und NAvigation

and Ranging)

A method for determining the distance

between a point and the position of a

sound source by measuring the time

lapse between the origin of the sound

and its arrival at the point

Sound Ranging

D=1/2 t x 4,800 feet per second

In piloting, soundings are usually

taken every 5 minutes.

A fathometer may

establish a fix

when a navigator

has a chart

showing accurate

bottom contours,

but in practice it

usually serves as

a check.

Electronic navigation isa form of piloting.

Electronic Navigation

• Equipment malfunction

• Insufficient coverage

Disadvantages

• Unaffected by weather

• Determines ship position electronically

Advantages

RADAR

RAdio Detection And Ranging

Navigation system using reflected

pulses of energy

RADAR

Advantage of radar, as a navigationalaid, is that it does not require externaltransmitting stations.

Disadvantage of radar, as a navigationalaid, is that maximum range is currentlylimited to slightly more than line-of-sight.

Use Reliable Radar Targets

Lighthouse

Radar System

Targets appear on the scope as

bright spots of light called pips.

PIPS

The most common scope used is a planposition indicator (PPI), which gives abird’s eye view of the radar coveragearea, the transmitting ship in the center.

• It can be used at night and during periods of low visibility.

• A fix can be obtained from asingle object.

Advantages of radar as a navigational

aid include:

• Very accurate and rapid

• Used to locate and track storms

• Very important for ship safety

Long Range Navigation

Loran

Long range navigation system using

radio signals

Loran

Loran is a system

of radio signals

broadcast by

stations of known

position.

A loran fix is determined by a loranreceiver from the intersection of linesof position obtained from those shorestations.

Loran Receiver

The newest electronic navigation systemis the Global Positioning System (GPS).

Satellite Navigation

GPS Satellites

• Six 10,900-

mile-high

orbits

• 24 satellites

• Continuous

three-

dimensional

fix capability

• Fix accurate

to within

±10 meters

Global Positioning

System (GPS)

GPS Navigation

GPS is used for a wide variety of land

navigation purposes, including position

and direction-finding in many new cars

and golf carts.

• Smart bombs

• Cruise missiles

Military applications of GPS navigation

systems include guidance for:

Enhancement by to basic GPS: corrections to positioning information is determined by land-based receivers and transmitted to users. Capable of accuracy to within + 1 meter.

Differential GPS

Provides accurate and continuous

dead reckoning (DR) positions

Ship’s Inertial Navigation

System (SINS)

SINS gives ships an accurate andcontinuous dead reckoning positionusing three gyroscopes to determinelatitude, vertical, and longitude withgreat accuracy.

Submarines use SINS to navigate when

submerged for months even when

traveling under the Arctic ice cap.

Celestial

Sphere

Celestial Navigation

Branch of navigation in which position is determined by the aid of heavenly bodiessuch as the Sun, Moon, and selected starsand planets

The widespread availability of GPS is

fast making celestial navigation at sea

a vanishing art.

The sextant is used in celestialnavigation to measure the angle(altitude) between a heavenly bodyand the visible horizon.

Sextants

VERNIER

SCALE

MICROMETER

SCREWDRUM SCALE

ARC

SCALE

HORIZON

MIRROR

INDEX MIRROR

TELESCOPE

LENS

HOODINDEX ARM

Reading the Vernier Scale

Sextant — Nomenclature

Calculation of one's position on the

basis of distance run on various

headings since the last precisely

observed position, with as accurate

allowance as possible being made for

wind, currents, compass errors

Dead Reckoning

Visual Fix

Electronic/Celestial Fix

Dead Reckoning Position

Estimated Position

Plotting Symbols

DEAD RECKONING TRACK

FIX

DR POSITIONDESTINATION

1200

Set and Drift

Set – The direction in which a ship

is forced by wind and current

Drift – The speed of that force in

knots

Effect of Set and Drift

FIX

DR POSITIONDESTINATION

1200

1600

1615

A fix at 1200 is plotted and labeled.

A line is drawn from the fix on the

ship’s course of 073°. Course is

labeled above the line, and the

speed of 15 knots is labeled below

the line.

To find the 1300 DR position, use

dividers to measure 15 minutes of

latitude on the vertical latitude

scale printed on the side of the

chart.

The spot is labeled ―1300DR.‖

The Captain orders the Officer

of the Deck (OOD) to put ship on

a new course, 117° at 1330.

Using dividers, mark a spot 7½

miles from the 1300 DR position

along the direction the ship is

steaming.

Label position 1330DR, and draw a new course line in the direction of 117°.

Plotting a ship’s

DR track from one

fix to the next is a

continuous

process while

underway.

1400 FIX

DR PLOT

1400 FIX

At sea, the navigator will use celestial or

electronic means to get positive fixes at

least every morning, noon, and evening.

In piloting waters, the navigator willnormally be on the bridge getting exactfixes whenever usable navigation aidscome into sight.

Currently, electronic plotters incorporatecontinuous fix updates received fromGPS, then project current ship’s positionand the DR track onto an electronic chartprojection on a computer screen.

Define navigation. Q.1.

Define navigation. Q.1.

The art and science by which

mariners find their ship's

position and guide it safely

from one point to another

A.1.

What is a chart? Q.2.

What is a chart? Q.2.

A type of map used to navigate

on water

A.2.

What are the imaginary lines

that run through the poles and

around the Earth?

Q.3.

What are the imaginary lines

that run through the poles and

around the Earth?

Q.3.

Meridians or lines of longitude A.3.

What divides the Earth into the

northern and southern

hemispheres?

Q.4.

What divides the Earth into the

northern and southern

hemispheres?

Q.4.

The Equator A.4.

What is a Great Circle? Q.5.

What is a Great Circle? Q.5.

Any circle drawn around the

Earth, the plane of which

divides the Earth into two equal

parts

A.5.

Are all meridians great circles? Q.6.

Are all meridians great circles? Q.6.

Yes A.6.

What is the name given to the

meridian on which the Royal

Observatory at Greenwich,

England, is located?

Q.7.

What is the name given to the

meridian on which the Royal

Observatory at Greenwich,

England, is located?

Q.7.

The Prime Meridian A.7.

Do parallel and latitudinal lines

run in the same direction?

Q.8.

Do parallel and latitudinal lines

run in the same direction?

Q.8.

Yes A.8.

Navigators determine their

ship's position using what

coordinate system?

Q.9.

Navigators determine their

ship's position using what

coordinate system?

Q.9.

Latitude and Longitude A.9.

If the latitude of the equator is

0 degrees, what is the latitude

of the North Pole?

Q.10.

If the latitude of the equator is

0 degrees, what is the latitude

of the North Pole?

Q.10.

90 degrees or north A.10.

Latitude and longitude are

expressed in what units?

Q.11.

Latitude and longitude are

expressed in what units?

Q.11.

Degrees, minutes, and

seconds

A.11.

How many degrees are there in

a circle?

Q.12.

How many degrees are there in

a circle?

Q.12.

360 A.12.

Approximately how many

yards are in a nautical mile?

Q.13.

Approximately how many

yards are in a nautical mile?

Q.13.

2000 yds. A.13.

What are meridians? Q.14.

What are meridians? Q.14.

Great Circles which pass

through the Earth’s poles

A.14.

In navigation what is a ―knot?‖ Q.15.

In navigation what is a ―knot?‖ Q.15.

A seagoing term meaning one

nautical mile per hour

A.15.

How is direction expressed? Q.16.

How is direction expressed? Q.16.

As an angle between 000

degrees and 359 degrees

A.16.

What are the cardinal points? Q.17.

What are the cardinal points? Q.17.

North, East, South, and West A.17.

Define ―true bearing.‖ Q.18.

Define ―true bearing.‖ Q.18.

The direction of an object

measured clockwise from true

north

A.18.

What does chart projection

entail?

Q.19.

What does chart projection

entail?

Q.19.

Projecting a three-dimensional

object on a two-dimensional

plane

A.19.

What is the best-known map or

chart projection called?

Q.20.

What is the best-known map or

chart projection called?

Q.20.

Mercator projection A.20.

What are the three basic types

of charts used by the Navy?

Q.21.

What are the three basic types

of charts used by the Navy?

Q.21.

a. Navigational

b. Harbor

c. General ocean sailing charts

A.21.

What is a cartographer? Q.22.

What is a cartographer? Q.22.

One who makes maps and

charts

A.22.

What is a fix? Q.23.

What is a fix? Q.23.

An accurate position

determined without reference

to any previous position. The

intersection of 2 or more lines

of position.

A.23.

What is the difference between

directions measured on a

gyrocompass and those

measured on a magnetic

compass?

Q.24.

What is the difference between

directions measured on a

gyrocompass and those

measured on a magnetic

compass?

Q.24.

Directions measured on a gyrocompass are relative to true north, whereas directions measured on a magnetic compass are relative to magnetic north.

A.24.

How is distance on a Mercator

chart measured?

Q.25.

How is distance on a Mercator

chart measured?

Q.25.

On a flat surface along any

meridian where one minute of

latitude equals one nautical

mile

A.25.

If a half-inch on a chart

represents 10 miles, how many

inches would represent 100

miles?

Q.26.

If a half-inch on a chart

represents 10 miles, how many

inches would represent 100

miles?

Q.26.

Five inches A.26.

What is the shortest distance

between two points on a

globe?

Q.27.

What is the shortest distance

between two points on a

globe?

Q.27.

An arc of a great circle A.27.

How many feet are in one

fathom?

Q.28.

How many feet are in one

fathom?

Q.28.

Six feet A.28.

What is a line of position

(LOP)?

Q.29.

What is a line of position

(LOP)?

Q.29.

A line drawn on a chart along

which a ship must be located,

based on a bearing or distance

from an object or landmark

A.29.

A ship that is traveling south

observes another ship on a

relative bearing of 041 degrees.

What is the true bearing to that

ship?

Q.30.

A ship that is traveling south



What is the true bearing to that

ship?

Q.30.

221 degrees true

(180 degrees + 041 degrees)

A.30.

A ship that is traveling north



Where would you see that ship

in relation to your ship?

Q.31.

A ship that is traveling north



Where would you see that ship

in relation to your ship?

Q.31.

Off the starboard bow A.31.

A round body whose surface is at all

points equidistant from the center

Sphere

A great circle of the Earth passing

through the poles and any given

point on the Earth's surface

Meridian

Lines of latitude with only the equator

being a great circle

Parallel

A two–pointed compass used for

dividing lines and measuring

Dividers

Compass Card

A circular card with magnets attachedto its underside, the face divided on itsrim into points of the compass, degreesclockwise from north, or both, andfloating or suspended from a pivot soas to rotate freely

Directional instrument that points to

the north magnetic pole

Magnetic Compass

Aligned with true north by means of a

spinning gyroscope

Gyrocompass

The state of being misrepresented

a false

Distortion

Development

of a Mercator

Projection

Sounding

LORAN CHART

Electronic navigation system using

satellites

Global Positioning System (GPS)

Intro to Navigation

Education

Transcript of Intro to Navigation