This document provides an overview of the Instrument Landing System (ILS) used at airports. It describes the key components of the ILS, including the localizer which provides horizontal guidance to the runway centerline, the glide slope which provides vertical guidance for descent, and marker beacons which indicate distances from the touchdown point. It also discusses the Airport Authority of India which manages airports in the country and works to modernize facilities to international standards. The ILS enables aircraft to land safely when visibility is low using radio signals to guide the pilot.

1. 12-Sep-16Shwetank Sharma 13EVJEC029
Vivekananda Institute Of Technology
Summer Training Report On
“Instrument Landing System”

2. CONTENT
 Introduction
 Preface
 Aircraft Landing System(ALS)
 Instrument Landing System(ILS)
 The Localizer
 Glide-Slope System(Glide Path)
 The Locator
 Distance Measuring Equipment (DME)
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3. INTRODUCTION
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 Airport Authority Of India
The Airports Authority of India (AAI) was formed on 1st April
1995 by merging the International Airports Authority of India and the
National Airports Authority with a view to accelerate the integrated
development, expansion and modernization of the operational,
terminal and cargo facilities at the airports in the country conforming
to international standards.
 AAI manages 126 airports, which include 11 international airports, 89
domestic airports and 26 civil enclaves at Defense airfields.
 AAI provides air navigation services over 2.8 million square nautical
miles of airspace.

4. AIRCRAFT LANDING SYSTEM
 The flight of an aircraft culminates in a landing at an airport .
 While approaching the airport , the aircraft takes a path in
line with the runway and from a certain distance begin to
descend until it touches the ground at a near the runway
threshold .
 When visibility is good ,weather in day or night then the
landing is performed under “Visual Flight Rules”(VFR)
condition.
 Usually this is taken to indicate a horizontal visibility of 5km
and vertical visibility of 300mt.
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5. INSTRUMENT LANDING SYSTEM
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 The Instrument Landing System(ILS) comprises of
following units :-
The Localiser
Glide-Path
Marker Beacons

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 The basic philosophy of ILS is that ground
installations, located in the vicinity of the runway,
transmit coded signals in such a manner that pilot is
given information indicating position of the aircraft
with respect to correct approach path.
 To provide correct approach path information to the
pilot, three different signals are required to be
transmitted. The first signal gives the information to
the pilot indicating the aircraft's position relative to
the center line of the runway.

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 The second signal gives the information indicating
the aircraft's position relative to the required angle of
descent, whereas the third signal provides distance
information from some specified point.
 These three parameters which are essential for a safe
landing are Azimuth Approach Guidance, Elevation
Approach Guidance and Range from the touch down
point.

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11. THE LOCALIZER
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 The Localizer operates in the VHF band (108-
110MHz) and consist of a transmitter with an
antenna system , the radiation of which has two
lobes .
 The two lobes are as follows :-
One with predominant modulation of 90 Hz.
The other with a predominant modulation of 150 Hz.

13. GLIDE PATH
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• The principle of the glide path is null type which is
similar to that of localizer.
• The system, which operates in the band 339.3-
335MHz employs two antennas , which have vertical
polar diagrams.
• The function of the Glide Path unit is to provide,
within its coverage limits, an inclined plane aligned
with the glide path of the runway for providing
elevation guidance to landing aircraft.

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Name of the
Equipment
Frequency band Uses
NDB 200 – 450 KHz Locator, Homing &En-route
HF 3 – 30 MHz Ground to Ground/Air Com.
Localizer 108 – 112 MHz Instrument Landing System
VOR 108 – 117.975 MHz Terminal, Homing &En-
route
VHF 117.975 – 137 MHz Ground to Air Comm.
Glide Path 328 – 336 MHz Instrument Landing System
DME 960 – 1215 MHz Measurement of Distance
UHF LINK 0.3 – 2.7 GHz Remote Control, Monitoring
RADAR 0.3 – 12 GHz Surveillance

16. Jaipur’s GLIDE PATH
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18. Marker Beacons
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 The ILS employs three marker beacons which give an
indication in the aircraft when it passes over them .
 All of them operates at 75MHzand work with with an
antenna which gives an fan shaped beam which is
typically ±40ºwide along the approach path and ±
80º perpendicular to it .
 The most distant one is called outer marker is
approximately 7 km from the touch down point on
the runway.

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 The radiation is modulation at 400 Hz , giving two
dashes per-sec.
 The second one is called middle marker is placed
where the glide path is 200 ft. (approx 60m),which is
generally 1 km from the touch down point.
 The modulation is as 1300 Hz with one dash every
2/3 sec
 The inner marker is placed where the glide path is
100 ft (approx 30m) above the ground.

21. RUNWAY LIGHTENING SYSTEM
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THANKYOU