The document is a project report submitted by a student on Communication, Navigation and Surveillance (CNS) systems used by Airports Authority of India (AAI). It includes sections on functions of AAI, an introduction to CNS systems, and descriptions of various components that comprise CNS systems including VHF communication, flight planning, NOTAM, ILS, radar, HF radio communication, AMSS, and VOLMET. The document provides an overview of the key technologies and systems used for air traffic communication, navigation, and surveillance in India.

1. Airports Authority of India
Regional Training Center (CNS),ER
N.S.C.B.I Airport,Kolkata-700052
A Project Report On-
Communication, Navigation and Surveillance (CNS)
Submitted By-
Arnab Bhattacharya,
B.Tech(ECE), 3rd
year
JIS College of Engineering,
Kalyani

2. Contents
• Acknowledgement.
• Introduction Of AAI.
• Functions of AAI
• CNS (Communication Navigation Surveillance).
• Communication Briefing.
• Flight Plan &Notam
• VHF Communication.
• HFRT Communication.
• AMSS (Automatic Message Switching System).
• VOLMET.
• ILS (Instrument Landing System).
• VOR & DVOR.
• DME.
• RADAR.
• ATCRBS
• ASMCGS.
• HF Transmitter.
• HF Receiver.
• ADS.
• Conclusion.
• Reference.

3. Acknowledgement
I take this opportunity to express my profound gratitude and
deep regards to my guide Mr Subikash Roy AGM (Com.ops)
for his exemplary guidance, monitoring and constant
encouragement throughout this training. Sitting at the office
of the airport and listening to the lectures of the aircraft
communication ,made us think that it was an easy task to fly
into the vast expanse on “CNS(COMMUNICATION
NAVIGATION & SURVEILLANCE)”,but it was only when
we gathered knowledge about this topic, we realized how
much helpful were some people to us. Without them this
exploration could never have been materialized.
Acknowledgement is something which really comes from the
bottom of the heart of every writer .I am obliged to staff
members at AAI of NSCBI airport, for the valuable
information provided by them in their respective fields. I am
grateful for their cooperation during the period of my
assignment.

4. Faculties of AAI
HFRT & COMM. BRIEFING - GAURI SHANKAR GHOSH [AGM]
(COM-OPS)
EQUIPMENT - SANJEEV SARKAR [AM] (ELEX)
TX STSN.(GARUI) - DEBASISH BISWAS [AGM] (CNS)
AMSS THEORY - P.K. BASU [AGM] (COM-OPS)
AMSS HARDWARE - P.K. MAJUMDAR [AGM] (COM ELEX)
DVOR & DME - BARUN KUMAR KHAMRU [AGM]
ILS - S. SUR [DGM] (CNS)
RADAR - SISIR KUMAR DE [JGM] (CNS)
ASMGCS - SHEKHAR ACHARYA
RX( BADU) - J. MAJUMDER [AGM]
VHF - SUDIP KUMAR BANERJEE [AGM] (C-T)
ILS - DVOR - P.K.MUHURY

5. Introduction To Regional Training Centre
(CNS), Eastern Region of AAI
Airports Authority of India (AAI) was constituted by an Act
of Parliament and came into being on 1st April 1995 by
merging erstwhile National Airports Authority and
International Airports Authority of India. The merger brought
into existence a single Organization entrusted with the
responsibility of creating, upgrading, maintaining and
managing civil aviation infrastructure both on the ground and
air space in the country. It covers 2.8 million square nautical
miles area which includes oceanic area of 1.7 million square
nautical miles.
During the year 2008-09, AAI handled aircraft movement
of 1306532 nos. [International 270345 & domestic
33785990] and the cargo handled 499418 tones
[international 318242 & domestic 181176].

6. Functions of AAI
The functions of AAI are as follows:
1. Design, Development, Operation and Maintenance of
international and domestic airports and civil enclaves.
2. Control and Management of the Indian airspace
extending beyond the territorial limits of the country, as
accepted by ICAO.
3. Construction, Modification and Management of
passenger terminals.
4. Development and Management of cargo terminals at
international and domestic airports.
5. Provision of passenger facilities and information system
at the passenger terminals at airports.
6. Expansion and strengthening of operation area, viz.
Runways, Aprons, Taxiway etc.
7. Provision of visual aids.
8. Provision of Communication and Navigation aids, viz.
ILS, DVOR, DME, Radar etc.

7. Communication Navigation Surveillance
(CNS)
Communication, Navigation and Surveillance are three main
functions (domains) which constitute the foundation of Air Traffic
Management (ATM) infrastructure.
The following provide further details about relevant domains of CNS:
Communication:-Communication is the exchange of voice and
data information between the pilot and air traffic controllers or flight
information centres.
Navigation:- Navigation Element Of CNS/ATM Systems Is meant
To provide Accurate, Reliable And Seamless Position Determination
Capability toaircrafts.
Surveillance:- The surveillance systems can be divided into two
main types:- Dependent surveillance and Independent surveillance. In
dependent surveillance systems, aircraft position is determined on
board and then transmitted to ATC. The current voice position
reporting is a dependent surveillance systems in which the position of
the aircraft is determined from on-board navigation equipment and
then conveyed by the pilot to ATC. Independent surveillance is a
system which measures aircraft position from the ground. Current
surveillance is either based on voice position reporting or based on
radar (primary surveillance radar (PSR) or secondary surveillance
radar (SSR)) which measures range and azimuth of aircraft from the
ground station.

8. FLIGHTPLAN (FPL) & NOTAM
The figure above shows the International Flight Plan registration
form.The main information provided in the flight plan is as follows:
• 7 letter Aircraft Identification Code
• Flight Rules - I (IFR), V (VFR) or Y (Both)
• Type of Flight – N (Non Scheduled), S (Scheduled) or M
(Military)
• Number – Denotes number of aircraft (1 for normal flights,
more for formation flights)
• Type of Aircraft – Boeing (B737), Airbus (A320, A380), ATR
flights (AT72), etc.
• Wake/Turbulence Category – L (Light, less than 7000Kg),
M(Medium, 7000-136000Kg) or H(Heavy, greater than
136000Kg)
• Equipment – N (NDB), V (DVOR), I (ILS), etc.
• Departure Aerodrome (4 letter Airport Identification Code)

9. • Time – Time of departure in GMT
• Cruising Speed (expressed in Nautical Miles per hour)
• Level – Denotes flight level or the altitude
• Route – The full route from source to destination, via all the
major airports
• Destination Aerodrome (4 letter Airport Identification Code)
• Estimated time to reach destination aerodrome
• 1st alternate aerodrome
• 2nd alternate aerodrome
NOTAMis quasi-acronym for “Notice To Airmen”. NOTAMs are
created & transmitted to all airport operators under guidelines
specified by Annex 15.
Aeronautical Information Services of the Convention on International
Civil Aviation (CICA) specified the term NOTAM for more formal
notice to airman following the ratification of CICA, which came into
effect on 4th April, 1947.
Previously NOTAM from a particular airport was published after a
specific time. Due to various developments of AAI now-a-days it is
possible to automatically update the information i.e. NOTAM to
pilots.
NOTAM is issued (and reported) for a numbers of reasons
following:
• Hazards such as air-shows, parachute jumps, kite flying etc.
• Flights by important people such as heads of state (Terminal
Flight Restrictions, TFRs).
• Closed runways.
• Inoperable radio navigational aids.
• Military exercises with resulting airspace restrictions.
• Inoperable light on tall obstructions.

10. • Temporary erection of obstacles near airfields.
• Passages of flocks of birds through airspace (a NOTAM
in this category is known as BIRDATM).
• Notifications of runway/taxiway/apron status with
respect to snow, ice & standing water (SNOWTAM).
• Notification of an operationally significant change in
volcanic ash or other dust contamination (an ASHTAM).
• Software code risk announcements with associated
patches to reduce specific vulnerabilities.
• Aviation authorities typically exchange NOTAMs over
AFTN circuits

11. VHF (Very High Frequency)
(Frequency range : 30 - 300 MHz.)
Very high frequency (VHF) is the radio frequency range from
30 MHz to 300 MHz. Frequencies immediately below VHF are
denoted High frequency (HF), and the next higher frequencies are
known as Ultra high frequency (UHF). The frequency allocation is
done by ITU.
These names referring to high-end frequency usage originate from
mid-20th century, when regular radio service used MF, Medium
Frequencies, better known as "AM" in USA, below the HF.
Currently VHF is at the low-end of practical frequency usage, new
systems tending to use frequencies in SHF and EHF above
the UHF range. See Radio spectrum for full picture.
VHF propagation characteristics are ideal for short-distance
terrestrial communication, with a range generally somewhat farther
than line-of-sight from the transmitter (see formula below). Unlike
high frequencies (HF), the ionosphere does not usually reflect VHF
radio and thus transmissions are restricted to the local area (and
don't interfere with transmissions thousands of kilometres away).
VHF is also less affected by atmospheric noise and interference
from electrical equipment than lower frequencies. Whilst it is more
easily blocked by land features than HF and lower frequencies, it is
less affected by buildings and other less substantial objects than
UHF frequencies.
Two unusual propagation conditions can allow much farther range
than normal. The first, tropospheric ducting, can occur in front of
and parallel to an advancing cold weather front, especially if there
is a marked difference in humidities between the cold and warm air

12. masses. A duct can form approximately 250 km (155 mi) in
advance of the cold front, much like a ventilation duct in a
building, and VHF radio frequencies can travel along inside the
duct, bending or refracting, for hundreds of kilometers.
certain subparts of the VHF band have the same use around the
world. Some national uses are detailed below.
108–118 MHz: Air navigation beacons VOR and Instrument
Landing System localiser.
118–137 MHz: Airband for air traffic control, AM, 121.5 MHz is
emergency frequency
Frequency Bands:
128.850-132.000 - This is the primary VHF band for
communications among the airlines. There are some additional
frequencies now allocated in the range136.500-136.975 - Not all
frequencies in this band are for the airlines, but this would be the
basic search range.
HF Airline bands will be added at a later timeFrequency Bands:
128.850-132.000 - This is the primary VHF band for
communications among the airlines. There are some additional
frequencies now allocated in the range136.500-136.975 - Not all
frequencies in this band are for the airlines, but this would be the
basic search range.

13. VHF AM Transmitter
• Frequency range — On the basic of frequency range, the
transmitters may be —
• (a) Medium wave transmitters—They operate over a range
of 550 to 1650 kHz frequency.
• VHF/UHF transmitters—They operate in V.H.F. (30-300
MHz) or U.H.F. (300 to 3000 MHz) range of frequencies.
They are used for F.M. radio, T.V., radio telephony, etc.
• Microwave transmitters — These transmitters are used on
frequencies above 1000 MHz. Their application is in radars.
• Short wave transmitters—They operate over a range of 3 to
30 MHz. ionosphere propagation is employed
VHF AM Receiver

14. HFRT COMMUNICATION
(FREQUENCY RANGE: 3 TO 30 MHz)
HFRT communication is the acronym of high frequency radio Tele
Communication. When aircraft crosses 200 NM radius from the
aerodrome, one of the ways of communication is HFRT
communication. It is a distant communication. Unlike VHF, it‟s
not dependent on line of sight (LOS) & it uses sky wave. Hence
distance communication is possible through HFRT. Mainly it is
used in oceanic region where there is no way to make
communication through VHF frequency range.
It is operated in two modes :
MWARA : Major World Air Route Area.
It is used for International Flight. The available frequencies for
MWARA in N.S.C.B.I Airport at Kolkata are:
10066 KHz ,6556 KHz ,3491 KHz, 2947 KHz.
Among these the first two are used during day (1st is main, 2nd is
standby) & other two frequencies are used at night.
RDARA : Regional Domestic Air Route Area.
It is used for Domestic Flight. The available frequencies for
RDARA in N.S.C.B.I Airport at Kolkata are:
8869 KHz, 6583 KHz, 8948 KHz, 5580 KHz, 2872 KHz.
These are also operated in the same manner as MWARA.

15. En-route VHF frequency for Kolkata HFRT is 127.3 MHz.
HFRT is very noisy because transmission is done using
ionospheres reflection.
Imaginary points on different routes are named to facilitate
aircrafts navigation. Some names are : DOPID, BBKO, MABUR,
BINDA etc.
The difference in elevation levels that can be assigned to flight in
the same direction is 1000 ft and in opposite direction it is 2000 ft.
Minimum horizontal separation between any two aircrafts is 10
NM.

16. AMSS
AMSS is a computer based system, centered on the Aeronautical
Fixed Telecommunication Network (AFTN) for exchange of
Aeronautical messages by means of auto-switching for distribution of
messages to its destination(s). This system works on store and
forward principle.
AMSS is an acronym for Automatic Message Switching System. It
has four major areas:
(1) System (2) Switching (3) Messages (4) Automation
System:AMSS is a dual architecture computer based system which
consists of few servers and workstations which are linked to each
other over a local area network as well as other equipment/devices
for data communication.
Messages:AMSS is mainly for exchange of AFTN messages, but at
the same time AMSS can handle some non-AFTN messages like
AMS messages (formally known as HFRT/Radio messages).
Switching:AMSS receives the messages from the terminals
connected via other switches, and after analyzing, stores the
messages as well as automatically retransmits the messages to their
destination. During the above process it uses switching system,
which allows on demand basis the connection of any combination of
source and sink stations. AFTN switching system can be classified
into three major categories:
1)Line Switching 2)Message Switching 3)Packet Switching
Automation:So far as automation is considered for any system, it
could be achieved by means of mechanical devices like relay etc.
and/or application software design as per requirement. InElectronics

17. Corporation of India Limited (ECIL) AMSS, maximum features of
automation like message switching, analyzing, storing, periodical
statistics etc. are taken care of by AMSS software and few means of
mechanical system.
Hardware Configuration
AMSS consists of three major components:
1) Core System 2) Recording System 3) User‟s terminal
1. Core System:It incorporates communication adapters,
protocols/suites, routing and gateway facilities. The core system is
composed of two identical computer machines (known as AMSS
main servers) which run in an operational/hot standby combination.
Both units supervise each other„s software and hardware
2. Recording System:It has two identical mass data storage
devices for storing of all incoming and outgoing AFTN messages. It
also has two identical mirrored Database servers which are operated
in parallel. The mirroring between the two database servers is
performed in the background to store specified type messages like
NOTAM, MET, ATC, HFRT, with no effect on the regular operation.
3. User’s Terminals:It is the interface between user and the
system with capability for uniform administration and monitoring
facilities for all system components, networks and data as well as
exchange of data as per requirement of users vide different type
application software. Any number of user terminals (maximum 60)
can be installed and used simultaneously.

18. VOLMET
VOLMET or metrological information for aircraft in flight, is a
worldwide network of radio stations that broadcast TAF, SIGMET &
METAR reports on shortwave frequencies and in some countries on
VHF too. Reports are sent in upper sideband mode, using automated
voice transmissions.
Pilots on international routes, such as North Atlantic Tracks, use this
transmissions to avoid storms & turbulence, and to determine which
procedures to use for descent, approach and landing.
The VOLMET network divides the world into specific regions and
individual VOLMET stations, each region broadcast weather reports
for specific groups of air terminals in their region at specific times,
coordinating their transmissions schedules so as not to interfere with
one another. Schedules are determined in the intervals of 5 minutes,
with one VOLMET station in each region broadcasting reports for a
fixed list of cities in each interval. These schedules repeat in every 30
minutes.

19. ADS – Automatic Dependent Surveillance
Automatic:The system operation is automatic, with no direct action
by the pilot
Dependent:The system‟s accuracy is dependent on on-board
navigation and other data sources (e.g. FMS) to provide the data to be
broadcast
Surveillance:The data is used for air and ground surveillance
Forms of ADS
ADS Contract (ADS-C)
The aircraft provides the information to the ground system in
four ways:
1)demand report 2)event report 3)periodic report4)
emergency report.
ADS Broadcast (ADS-B)
The data is broadcast. The originating aircraft has no
knowledge of who receives and uses the data and there is no 2-way
‘contract’or interrogation
ADS-B is a surveillance application that involves a broadcast of
position to multiple aircrafts or multiple ATM units.
Each ADS-B equipped aircraft or ground vehicle periodically broad
casts its position and other relevant information derived from on
board equipment.
ADS-B is currently defined for LOS operations (over VDL or Mode-S)
It can be used as alternative to ASDE
It has the potential to complement SSR.

20. ADS B – Automatic Dependent Surveillance
- Broadcast
Position Reports Position Reports
ADS B
Ground Station
ADS ARCHITECTURE
ARINC SITA
Aircom Service Providers
AFTN
Satcom VHF
ACARS MU
Decides whether to use
VHF or SATCOM
FMC/FANS
ATSU 2
ATSU 1
VHF Ground
StationGround Earth Station
INMARSAT
GNSS
ARINC SITA
Aircom Service Providers
AFTN
Satcom VH F
ACARS M U
Decides whether to use
VHF or SATCOM
FM C/FANS
ATSU 2
ATSU 1
VH F G round
StationG round Earth Station
INM ARSAT
G NSS

21. CONTROLLER PILOT DATA LINK
COMMUNICATION (CPDLC)
• A means of digital communication between controller and pilot,
using data link instead of voice
• Initial application for en-route operations in areas where the use
of voice communication is considered not efficient.
• CPDLC message have a standard formats, using familiar ICAO
phrases.
• Before sending a CPDLC message, it can be viewed on the
computer display unit and modified, if required.
Advantages of CPDLC over Voice Communications
• Significant reduction of workload for Pilot and Controller
• Alleviate voice channel congestion problems
• Allow ATC to handle more traffic
• Eliminate misunderstanding of poor voice quality
• Eliminate misinterpretation and corruption due simultaneous
voice transmission
• Significant reduction of response time
• Automatic down linking a report such as way point crossing

22. HF RECEIVER
• ICOM Receiver (made in Japan) is used in AAI, Kolkata. It is a
wideband receiver. Its features are following:
• Frequency coverage is : 100 KHz to 1 GHz.
• It is a multipurpose receiver with different modes :
• Upper Side Band.
• Lower Side Band.
• Continuous Wave.
• Frequency Shift Keying.
• Amplitude Modulation.
• Narrow Band Frequency Modulation.
• Wide Band Frequency Modulation.
• Receiver type :Superheterodyne system.
• Sensitivity : 2 µV. This is the minimum voltage that can be
detected by the receiver.
• Audio Output Impedance : 4 to 8 ohms.

23. ASMGCS
(ADVANCED SURFACE MOVEMENT
GUIDANCE AND CONTROL SYSTEM)
A system providing routing, guidance and surveillance for the control
of aircraft and vehicles in order to maintain the declared surface
movement rate under all weather conditions within the Aerodrome
Visibility Operational level (AVOL) while maintaining the required
level of safety.

24. Surface Movement Radar (SMR)

 Used to detect aircraft and vehicles
on the surface of an airport.
 Used by Air Traffic Controllersto
supplement visual observations.
 Also used at night time and during
low visibility to monitor the
movement of aircraft and vehicles
Multilateration System

26. Radar
RADAR is an acronym coined by the US Navy from the words RAdio
Detection And Ranging.
Radar is basically a means for gathering information about distant
objects called “targets” by sending electromagnetic waves at them and
analysing the returns called the “echoes”.
CLASSIFICATION OF RADARS
Primary Radar:Cooperation of targets are not required for
detection.
Secondary Radar:Active cooperation of targets are required for
finding range and other details of the targets.
CW Radar:Can detect moving targets and it‟s velocity.
CW FM Radar: Can detect range using FM Signals. Pulsed Radar:
Uses pulse modulated micro wave signals for detecting range and
velocity of targets.
Primary Radar
Antenna Propagation
Transmitted pulse

27. Secondary Radar
MAXIMUM RANGE OF A RADAR depends on:
• Peak transmission power (4th
root)
• Minimum detectable signal (MDS)
• Antenna Gain
• Radar cross section of the target
• Atmospheric attenuation
In AAI RADARs available at:
• Kolkata, Chennai, Guwahati, Ahmedabad, Berhampur, Nagpur,
Varanasi, Mangalore
• Delhi and Mumbai
• Hyderabad and Bangalore
• Kolkata, Chennai, Bellary, Vizag, Katihar, Jharsuguda, Bhopal,
Porbandar and Udaipur
• Kolkata, Chennai, Mumbai, Trivandrum, and Delhi

28. MSSR
MSSR INTERROGATION
 The interrogator transmits a pair of pulses at 1030 MHz.
 Each pulse has the same duration, shape and amplitude.
 Their spacing distinguishes various modes of interrogation
 P2 pulse use is for control

29. DME : Distance Measuring Equipment
Distance measuring equipment (DME) is a transponder-based radio
navigation technology that measures slant range distance by timing
the propagation delay of VHF or UHF radio signals.
Frequency Bands : UHF (300 MHz to 3GHz)
960 MHz to 1215 MHz(For DME)
Aircraft use DME to determine their distance from a land-based
transponder by sending and receiving pulse pairs – two pulses of fixed
duration and separation. The ground stations are typically co-located
with VORs. A typical DME ground transponder system for en-route
or terminal navigation will have a 1 kW peak pulse output on the
assigned UHF channel.
A low-power DME can be co-located with an ILS Localiser antenna
installation where it provides an accurate distance to touchdown
function, similar to that otherwise provided by ILS Marker Beacons.
The DME system is composed of a UHF transmitter/receiver
(interrogator) in the aircraft and a UHF receiver/transmitter
(transponder) on the ground.

30. ILS
The full form of ILS is Instrument Landing System.The Instrument
Landing System (ILS) provides a means for safe landing of aircraft at
airports under conditions of low ceilings and limited visibility.
The components of ILS are:
1. Localiser
2. Glide path
3. Marker Bacons
4.L P DME
ILS Parameter ILS Component
a. Azimuth Approach Guidance Provided by Localizer
b. Elevation Approach Guidance Provided by Glide Path
c. Fixed Distances from Threshold Provided by Marker Beacons
d. Range from touch down point Provided by DME

31. Locations of ILS components
l

32. Bibliography
•Training material provided by the Airports Authority Of India
•www.aai.aero
•Electronic Communication System by Kennedy & Davis.
•http://en.wikipedia.org/wiki/Instrument_landing_system
• http://en.wikipedia.org/wiki/Radar
•http://en.wikipedia.org/wiki/Automatic_dependent_surveillanc

33. CONCLUSION
As an undergraduate of the JIS College of Engineering I would like to
say that this training program was an excellent opportunity for us
to get to the ground level and experience the things that we
would have never gained through going straight into a job. I am
grateful to Airports Authority Of India for giving us this wonderful
opportunity.
The main objective of the industrial training is to provide an
opportunity to undergraduates to identify, observe and practice how
engineering is applicable in the real industry. It is not only to get
experience on technical practices but also to observe live equipment
and to interact with the staff of AAI . It is easy to work with people,
but not with sophisticated machines. The only chance that an
undergraduate has to have this experience is the industrial training
period. I feel I got the maximum out of that experience. Also I learnt
the way of work in an organization, the importance of being punctual,
the importance of maximum commitment, and the importanceof team
spirit. The training included AMSS, VOLMET, ADS, CPDLC,
HFRECEIVER, ASMGCS, SMR,RADAR, DME,ILS. We learned
mot only through theory classes but also by practicals on live
equipments.In my opinion, I have gained lots of knowledge
andexperience needed to be successful in Aviation communication
engineering. As in my opinion,Engineering is after all a Challenge,
and not a Job.