radio navigation aids presentation 2 navaids radar

8/14/2019 Radio Navigation Aids Presentation 2 Navaids Radar

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Civil Aviation Training Institute

Civil Aviation Training InstituteCivil Aviation Training InstituteHyderabadHyderabad--PakistanPakistan


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Civil Aviation Training Institute, Hyderabad-Pakistan

Radio Navigational Aids

Radio Navigational AidsRadio Navigational Aids

ByByZulfiqarZulfiqarMiraniMiraniSenior Electronics EngineerSenior Electronics Engineer

School of Electronics EngineeringSchool of Electronics Engineering


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Navigation

Navigation systems are the basis for an aircraft's ability to get from oneplace to another and know where it is and what course to follow. It'smore than just maps. The closest thing today's automobiles come to anaviation navigation system is the "navigation center" some automobilescome with. These computers establish an automobile's position viasatellite and place the position on a moving map. Intelligenceprogrammed into the system allows the driver to navigate to destinationby executing instructions provided by the system.

Historically, aircraft navigated by means of a set of ground-based

beacons, each broadcasting on its own frequencies. Aircraft systemscould tune into the frequencies of two of these beacons and fly betweenthem (fromone beacon tothe next). Knowing where the aircraft isbetween two of these beacons allows the aircraft to know where it is in aglobal sense. Since the 1980s, aircraft systems have evolved towardsthe use of satellite navigation.


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Radio Navigation Systems

Types of Radio Navigation Systems

1) En-route Navigation

NDB (Radio Beacons)

VOR

DME

2) Aids to Approach, Landing and Departure

ILS


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Non Directional Beacon(NDB)


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Non Directional Beacon (NDB)

Purpose

It is used with direction finding equipment in the aircraft to

provide bearing information of a location on the air route orof an airport.

The NDB equipment is installed en-route areas as well as

on the airports to provide navigational guidance to the pilot.


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NDB: Operating Frequency:

ICAO has assigned Low and Medium Frequency band of200 1750 KHz for NDB operation; where as most of NDBequipments are found operating within frequency band of

200-525 KHz.


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NDB:

Construction

NDB consists of

LF/MF Transmitter LF/MF Antenna and

Monitor

Transmission

It radiates a non-directional pattern permitting reception fromany point within service range of the facility (usually 200 NM).Station identification code in the form of two letter Morse Codeis also transmitted by the NDB.


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NDB: Airborne Indication

An airborne radio direction finding (RDF) equipment oncetuned to the signal indicates bearing of the NDB transmitterwith respect to aircraft heading. Bearing Indicator displaysthe bearing of the station relative to the nose (heading) ofthe aircraft.Relative Bearingis the angle formed by the line drawnthrough the center line of the aircraft and a line drawn fromthe aircraft to the radio station.

Magnetic Bearingis the angle formed by a line drawn fromaircraft to the radio station and a line drawn from the aircraftto magnetic north (Bearing to station).


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NDB: Relative and Magnetic Bearing


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NDB: Airborne Equipment

Airborne equipments that interacts with NDB (groundstation) is called Automatic Direction Finder (A.D.F) andindicates bearing on a full 360 degree radial. Figure 2-3

shows pictures of ADF.


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NDB: Airborne Equipment -Samples


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NDB: ADF Airborne Indicators


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VHF Omni Range(VOR)


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VOR

Purpose

It is a radio aid that provides, with inter action of airborneequipment, information about azimuth, the course and TO-

FROM to the pilot.


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VOR: Information

AZIMUTH in VOR is a clockwise angle between magneticnorth and the line connecting the VOR and the aircraft. Theindication is displayed on an Omni Bearing Indicator in theaircraft.

The COURSE is the information whether aircraft is flying tothe left or right of, or exactly on the pre-selected course line.The course information is displayed on a Flight Path

Deviation Indicator.

TO-FROM indication tells the pilot whether an aircraft isapproaching to or moving away from VOR stations.


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VOR

Operating Frequency

VOR is assigned to operate in VHF band range from 112118 MHz.

Transmission

It radiates two radio signals modulated at 30 Hz, areference signalwhich has constant phase through out 360

degrees and a variable signalwhose phase varies withvariation in azimuth. Station identification code, consistingtwo or three letters, in the form of Morse code is alsotransmitted by the VOR.


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VOR: Some Considerations

The VOR is usually located at airfields but as they serveto define designated air routes [airways] they are alsoinstalled away from airfields, on the key air routelocations

As VHF transmissions are line-of-sight; the ground to airrange, thus, depends on the elevation of the transmittersite, the height of the aircraft and the power output. Any

obstacles (buildings, mountains or other terrain features,including the curvature of the earth) block VOR signalsand restrict the distance over which they are received ata given altitude.


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VOR: Airborne Indication

Indications of VOR information are given on airborneindicators as follows.

Course Selector is used in conjunction with left-right needleand To-From indicator to display VOR information.

This type of display is called Omni Bearing Indicator or

OBI (as commonly refereed by the pilots). The courseselection can be displayed on a 360 degree azimuth dial ora 3 digit counter.


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VOR: Airborne Indicators


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VOR: The Course Deviation Indication


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VOR: TO-FROM Information


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Distance Measuring EquipmentDistance Measuring Equipment

(DME)(DME)


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DMEDMEDME

The DME system is to provide continuous and accurate

indication of the slant range distanceslant range distance (expressed in nauticalmiles) of an equipped ground reference point (i,e ground

DME facility).

System Components:System Components:

The system consists of two basic components, one fitted

into the aircraft and the other installed on the ground.

The aircraft equipment is referred to as INTRROGATORINTRROGATOR

and the ground component as TRANSPONDERTRANSPONDER..


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DME: Operating FrequenciesDME: Operating FrequenciesDME: Operating Frequencies

The system operates within frequency band of 960 MHz to

1215 MHz.

The interrogation and Reply frequencies are assigned

frequencies with, at least, 1 MHz separation.

The DME operates in the ultra-high frequency (UHF) band

and therefore is restricted to line-of-sight transmission.


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DME: Principle of operationDME: Principle of operationDME: Principle of operation


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DME: Range DeterminationDME: Range DeterminationDME: Range Determination

Distance measurement in DME utilizes two way travel time

of the pulses and is called range timerange time. As used in DMErange timerange time is the interval of time between transmission of an

interrogation to the reception of a reply to that interrogation

(exclusive of system delay and pulse pair spacing).

Notice that range time is the time required for a signal to

travel a given distance twice, therefore range time for OneNM is the time it takes a signal to travel actual distance of

Two NM.


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DME: Range DeterminationDME: Range DeterminationDME: Range Determination


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DME: Capability and CoverageDME: Capability and CoverageDME: Capability and Coverage

Aircraft Handling Capability:Aircraft Handling Capability:

The transponder equipment should be capable of handling100 aircrafts or peak traffic which ever is less.

Coverage:Coverage:

DME facility provides coverage up to 200 NM.


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DME: Airborne IndicationDME: Airborne IndicationDME: Airborne Indication


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Instrument Landing SystemInstrument Landing System

(I.L.S)(I.L.S)


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ILSILSILS

It is a radio aid to the final approach and is used only within

a short distance from the airport. Its purpose is to help thepilot land the airplane. It is very helpful when visibility islimited and the pilot cannot see the airport and runway.

The landing path in ILS is determined by intersection of twoplanes a vertical plane and a horizontal plane. HorizontalHorizontalplaneplane contains information of the Central Line of a runway

and Vertical planeVertical plane provides Glide Path angle.


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ILS: ConstructionILS: ConstructionILS: Construction

Localizer

Glide Slope Marker Beacons

ILS comprises of the following three components or sub-

systems:


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ILS : Location and OperationILS : Location and OperationILS : Location and Operation


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ILS: LocalizerILS: LocalizerILS: Localizer

Localizer is installed at the STOP ENDSTOP END of a runway.

It provides central linecentral line information to the pilot approaching the

aircraft for landing. The localizer signal is transmitted at the far

end of the runway.

It is assigned specific transmitting frequency in the VHF band

ranging between 108 MHz to 112 MHz.

Each localizer is identified by two or three letter Morse code

designator preceded by the letter I, which is modulated at 1020

Hz signal and transmitted six times per minute. For example: IKCfor ILS of Karachi Airport.


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ILS: Localizer Airborne IndicationILS: Localizer Airborne IndicationILS: Localizer Airborne Indication


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ILS: Glide SlopeILS: Glide SlopeILS: Glide Slope

Glide slope is installed at the APPROACH END of a

runway. The transmitter is located 750 to 1,250 feet (ft)down the runway from the threshold, offset 400 to 600 ftfrom the runway centerline. The Glide path is adjusted toproject an angle of 20 (degrees) above the horizon. This

angle may vary between 20 and 4.50 degrees dependingupon obstructions along an approach angle.

Coverage:Coverage:The Glide Slope is to provide signals sufficient to allowsatisfactory operation in the sector of 8 degrees on eachside of the Glide path to a distance of 10 NM.


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ILS: Glide Path Airborne IndicationILS: Glide Path Airborne IndicationILS: Glide Path Airborne Indication


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ILS :ILS :ILS :


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ILS: Marker BeaconsILS: Marker BeaconsILS: Marker Beacons

Marker beacons associated with ILS are designated as:

Outer Marker (OM),

Middle Marker (MM)

Inner Marker (IM)

The Markers are located along a localizer front course at

specific distances from the approach endapproach end of the runway


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Outer MarkerOuter Marker

It is located at 4 to 7 miles from the approach end of a runway and

identified by transmission ofcontinuous dashes. The OM is modulatedat 400 Hz that activates PURPLE light on Pilots instrument panel.

Middle MarkerMiddle Marker

MM is located at approximately 3,500 feet (1050 meters) from theapproach end of runway and identified by transmission ofalternatingdots and dashes. The MM is modulated at 1,300 Hz that activatesAMBER light on Pilots instrument panel.

Inner MarkerInner Marker

IM is identified by transmission ofcontinuous dots transmitted at a rateof 6 dots per second. It is installed between 250 feet and 1500 feet (450meters) from the runway threshold. The signal is modulated at 3000 Hz

and activates WHITE light.


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RADARRADAR


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RadarRadarRadar

The term RADARRADAR is derived from RADIO DETECTIONRADIO DETECTION

AND RANGING.AND RANGING.

Radar is a method whereby radio waves are transmitted

into the air in a specific direction and are received whenthey are reflected by an object in the path of the beam.

RANGERANGE in RADAR is determined by measuring the time,radio wave takes, from the radiation to return of its echo;

whereas DIRECTION is determined from the position of

antenna at the time of reception of signal.


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FUNCTIONAL CLASSIFICATION OF ATC RADAR SYSTEMSFUNCTIONAL CLASSIFICATION OF ATC RADAR SYSTEMSFUNCTIONAL CLASSIFICATION OF ATC RADAR SYSTEMS

1. En-route Radar

2. Terminal Approach Radar3. Precision Approach Radar

4. Ground Movement Radar


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TYPES OF RADARTYPES OF RADARTYPES OF RADAR

Primary RadarPrimary Radar

It provides Range and BearingRange and Bearing information to the AirTraffic Control Center. It does not need cooperation of theaircraft for providing information as above for it dependsupon reflection of the radio waves transmitted by the system

itself.

Secondary RadarSecondary Radar

It provides identification and altitudeidentification and altitude information to groundATC. It works with cooperation of the aircraft. Theinformation produced by the Secondary Radar is thereforefunction of both ground equipment and airborne equipment.


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Primary Radar PrinciplePrimary Radar PrinciplePrimary Radar Principle

P i R d O ti

P i R d O tiP i R d O ti


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Primary Radar OperationPrimary Radar OperationPrimary Radar Operation


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Primary Radar IndicationPrimary Radar IndicationPrimary Radar Indication

S d R d O ti

S d R d O tiS d R d O ti


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Secondary Radar OperationSecondary Radar OperationSecondary Radar Operation

S d R d I di ti

S d R d I di tiS d R d I di ti


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Secondary Radar IndicationSecondary Radar IndicationSecondary Radar Indication


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Thank YouThank YouThank You

radio navigation aids presentation 2 navaids radar

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