2-9 electronic aids to navigation

8/11/2019 2-9 Electronic Aids to Navigation

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ElectronicElectronic

Aids toAids to NavigationNavigation

Kolegij: ENGLESKI JEZIK 2Kolegij: ENGLESKI JEZIK 2Profesor: BiseraProfesor: Bisera PlanPlanii

Student:Student: TinTin

PritiPritianacanac


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ElectronicElectronic

Aids toAids to NavigationNavigation

terrestrial radio navigation systemsterrestrial radio navigation systems

satellite navigation systemssatellite navigation systems

radar navigation systemsradar navigation systems


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Terrestrial Radio Navigation SystemsTerrestrial Radio Navigation Systems

Position is obtained by receiving

a radio signal from at least 3

different

coastal radiostations

(2 pairs). The signals are time delayed

and signal from each pair of stations when drawn on a chart

represents one hyperbolic line.

The intersections of 2 such lines

reveal the ship's position.

This is why this type of navigation is called

Hyperbolic navigation.

Because of different advantages and disadvantages and availabilitythese systems were often used in combination with one another or

other types of navigation.

The

best

known

terrestrial

radio navigation

systems:

DECCA

LORAN

OMEGA


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TerrestrialTerrestrial

RadioRadio NavigationNavigation

SystemsSystems

DECCA developed in UK during WW2 for Allied military purposes. Decca

system was one of the few, if not the only, position fixing system available

to many mariners. It's accuracy depended on many factors including

weather, time of the day and propagation conditions.

It had a range of

400NM during the day and up to 250 NM during the night. DECCA stopped

transmitting in 2000.

LORAN -

was developed in America during the WW2.It worked on the

similar principles as DECCA,

using hyperbolic

lines,

except

it had a longer

range-1200 M.

It also suffered from the signal delay and propagation

problems. The latest known variant of this system is LORAN-C which is stillin use but has been in steep decline, with the satellite based Global

Positioning System (GPS) being the primary replacement. USA and Canada

ceased transmitting LORAN-C signals in 2010.

OMEGA-

was the first truly global

radio navigation system.

It enabled shipsand aircraft to determine their position by receiving very low frequency

(VLF) radio signals transmitted by a network of fixed terrestrial radio

beacons.

It was very inaccurate

so it was used for ocean navigation and in

combination with other radio navigation systems. It became operational

around 1971 and was shut down in 1997.


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Satellite navigation systemsSatellite navigation systems

TRANSITTRANSIT

GPSGPS GLONASSGLONASS

GalileoGalileo CompassCompass


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TRANSIT / NAVSATTRANSIT / NAVSAT

TRANSITTRANSIT also known as NAVSAT was the first satellitealso known as NAVSAT was the first satellitenavigation system to be used operationally. The systemnavigation system to be used operationally. The systemwas primarily used by the U.S. Navy and later it was madewas primarily used by the U.S. Navy and later it was made

available for civilian use as well.available for civilian use as well. It used lower number ofIt used lower number ofsatsatttelites,elites, compared to GPS so the position could becompared to GPS so the position could beobtained only every hour or more,obtained only every hour or more, depending on latitude.depending on latitude. ItItalso had the distinct disadvantage that it generated twoalso had the distinct disadvantage that it generated twopossible locations for any given measurements very closepossible locations for any given measurements very close

to each other,to each other, so it was hard to determine what is the realso it was hard to determine what is the realposition.position. In combination with OMEGA it produced a highlyIn combination with OMEGA it produced a highlyaccurate global navigation system.accurate global navigation system. It ceased navigationIt ceased navigationservice in 1996.service in 1996.


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GPSGPS

GPSGPS-- Global Positioning System is a system thatGlobal Positioning System is a system that

provides location and time information in allprovides location and time information in allweather, anywhere on or near the Earth, where thereweather, anywhere on or near the Earth, where thereis an unobstructed line of sight to four or more GPSis an unobstructed line of sight to four or more GPSsatellites. It is maintained by the United Statessatellites. It is maintained by the United States

government and is freely accessible to anyone with agovernment and is freely accessible to anyone with aGPS receiver. It is highly accurate and most widelyGPS receiver. It is highly accurate and most widelyused satellite navigation system.used satellite navigation system.


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GLONASSGLONASS GLONASSGLONASS--currently the only alternative to the GPS. GLONASS is thecurrently the only alternative to the GPS. GLONASS is the

Russian sateRussian satelllitelite navigation system made available for civilian use innavigation system made available for civilian use in

2007. It is very slightly less accurate than GPS, but more accur2007. It is very slightly less accurate than GPS, but more accurate onate on

high latitudes. When used in combination with GPS it is fasterhigh latitudes. When used in combination with GPS it is faster,, moremoreaccurate than each system used alone, because than it has over 5accurate than each system used alone, because than it has over 500

satesatellliteslites available. That is why many new receivers support both GPSavailable. That is why many new receivers support both GPS

and GLONASS reception. It is expected that future improvements wand GLONASS reception. It is expected that future improvements willill

achieve accuracy up to 0.6 meters or better by 2020.achieve accuracy up to 0.6 meters or better by 2020.

GallileoGallileo,, Compass and othersCompass and others -- GallileoGallileo is future EU positioningis future EU positioningsystem that will be completed by 2020. and aims to be moresystem that will be completed by 2020. and aims to be more

accurate than other sataccurate than other satttelite position systems.elite position systems. Compass is theCompass is the

future Chinese satfuture Chinese satttelite position system.elite position system.


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RadarRadar navigationnavigation systemssystems

ARPAARPAAutomatic Radar Plotting AidAutomatic Radar Plotting Aid-- is an electronic computer systemis an electronic computer system

that uses radar data to plot targets and calculate the trackedthat uses radar data to plot targets and calculate the tracked object'sobject's

course, speed and closest point of approach (CPA), thereby knowicourse, speed and closest point of approach (CPA), thereby knowing ifng ifthere is a danger of collision with the other ship or landmass.there is a danger of collision with the other ship or landmass.

First ARPA units were standalone and were only an addition to thFirst ARPA units were standalone and were only an addition to thee

conventional radar unit.conventional radar unit.

Modern ARPA units are fully integrated with radar in one unit,Modern ARPA units are fully integrated with radar in one unit, with thewith themain operational advantage: both the radar and ARPA data are reamain operational advantage: both the radar and ARPA data are readilydily

comparable.comparable.

Today ARPA radars use modern types oToday ARPA radars use modern types off rasterscanrasterscan displays whichdisplays which

have many advantages such as: steady picture, colour and are dayhave many advantages such as: steady picture, colour and are daylightlightviewable due to increased brightness.viewable due to increased brightness.


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OtherOther electronicelectronic navigationnavigation aidsaids ECDISECDIS--electronic chart displayelectronic chart display

AISAIS--Automatic identification SystemAutomatic identification System--used for identifyingused for identifyingand locating vessels by electronically exchanging dataand locating vessels by electronically exchanging datawith other nearby ships and AIS Base stations. AISwith other nearby ships and AIS Base stations. AISinformation supplements marine radar, which continuesinformation supplements marine radar, which continuesto be the primary method of collision avoidance forto be the primary method of collision avoidance forwater transport.water transport.

RDFRDF--Radio direction finderRadio direction finder--still in use on coastal vesselsstill in use on coastal vesselsand as a backup for GPSand as a backup for GPS

Depth findersDepth finders

PitometerPitometer loglog--used to measure a ship's speed relative toused to measure a ship's speed relative tothe water.the water.


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ReferencesReferences

1.Boris1.Boris PritchardPritchard,,MaritimeMaritimeEnglishEnglish1,1,kolska knjiga, Zagreb 1995.kolska knjiga, Zagreb 1995.

2. http://www.2. http://www.jprocjproc.ca/.ca/hyperbolichyperbolic//

3.3.

http://http://msimsi..nganga..milmil//MSISiteContentMSISiteContent//StaticFilesStaticFiles/NAV_PUBS/RNM/310ch5.pdf/NAV_PUBS/RNM/310ch5.pdf

4.4. http://en.wikipedia.org/wiki/Satellite_navigationhttp://en.wikipedia.org/wiki/Satellite_navigation

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