utkarsh tiwari aai report

7/27/2019 Utkarsh Tiwari AAI Report

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VOCATIONAL TRAINING ON COMMUNICATION,

NAVIGATION AND SURVEILLANCE (CNS) REPORT

REGIONAL TRAINING CENTRE AIRPORTS AUTHORITY OF INDIA NETAJI SUBHASH CHANDRA BOSE INTERNATIONAL

AIRPORT, KOLKATA

Duration of Training: 18th to 29th June 2012

Submitted by

Utkarsh Tiwari

Registration No. - 108054 of 2009-10

Roll No. - 000910701063

Department of Electronics and Telecommunication Engineering UG 3rd Year

Jadavpur University, Kolkata


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Utkarsh Tiwari Jadavpur University

CERTIFICATEThis is to certify that Mr Utkarsh Tiwari has undergone Vocational Training at the Regional Training Centre Airports Authority of

India NSCBI Airport, Kolkata from 18 th June to 29th June 2012. To the best of my knowledge, this Project Report has not been

submitted for any other examination and does not form a part of any other course undergone by the candidate.

Signature (Course Coordinator)

Dated:

Place:Kolkata

Remarks:


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STUDENT DECLARATIONI hereby declare that vocational training report on:

COMMUNICATION, NAVIGATION AND SURVEILLANCE (CNS)

is submitted to

Regional Training Centre, Airports Authority of India NSCBI Airport

on the completion of Vocational Training at the Regional Training Centre, Airports Authority of India NSCBI Airport from 18 th to 29th

June 2012

.

Kolkata

Dated: Utkarsh Tiwari


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List of Contents

Topics Page No.

Acknowledgements 6 Special Thanks 8 About- Airports Authority of India (AAI) 9 AMSS 12 Comm. Briefing 16 HFRT Communication 21 Remote Transmitting and Receiving Stations 23 HF Transmitter 24 HF Receiver 26 DME 27 DVOR 29 Non-Directional Beacons 30 ILS 31 RADAR 34 ASMGCS 38 ADS 40 VHF 42

Some other relevant topics:

Radio Propagation 46 Runway Naming convention 48 VOLMET 50 CPDLC 51 SELCAL 53 NATO Alphabets 55 List of Important Airports in India 56 Cumulonimbus cloud 57 GAGAN 58

Different Control Regions 59

Conclusion 60 Bibliography 61


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Acknowledgements

I would like to express my heartfelt gratitude to Mr Subikash Roy AGM (Comm. Ops) and all other officers of Airports Authority of

India NSCBI Airport, Kolkata who gave me the opportunity to learn and interact with their extremely competent Officers, Engineers

and Staff and learn about the wonderful and diverse world of Communication, Navigation and Surveillance (CNS). The experiencewas extremely enriching and inspirational.

In my opinion the Communication, Navigation and Surveillance (CNS) division of Airport Authority of India provides best facility and

opportunity for training and internship in the field of Electronics and Communication Engineering (ECE). No other industry has

such extensive use of ECE engineering equipment. I therefore am overjoyed that I got an opportunity to undergo this extremely

informative and educational training in the CNS division of AAI, Kolkata for a period of 10 days which enabled me to get hands on

experience in the field of aeronautics telecommunication operation, equipment used and maintenance.

Besides the aspects of Communication Engineering, the training also gave me an opportunity to experience the industry

environment and the dedication and hard work it demands from an individual. I would once again like to thank everyone at Airport

Authority of India NSCBIA, Kolkata especially all the below mentioned officials who undertook our training sessions, by takingprecious time out for us despite their busy schedules

Departmental Officials:

RTC (CNS) ER

1. Sri Sisir Kumar De, Joint Manager (CNS)2. Sri Sukdeb Das, Assistant General Manager (Elex)3. Sri Subikash Roy, Assistant General Manager (Com-Ops)4. Mrs. Anju Kumari, Manager (Elex)

AMSS Hardware

Sri Upal Debnath, Assistant Manager (Elex)

AMSS

Sri Abhijit Bhattacharya, Assistant General Manager (Elex)

Comm. Briefing

Sri Gourishankar Ghosh, Senior Manager (Communications)

HFRT

Sri Gourishankar Ghosh, Senior Manager (Communications)

Equipment

Sri Atanu Bandyopadhyay, Manager (Technical)

DVOR


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Sri M. Sarkar, Senior Manager (ILS)

DME

Sri Adnan Khan, Manager (Elex)

ILS

Sri M. Sarkar, Senior Manager (ILS)

Transmitter Station

Sri Prasenjit Das, Junior Executive (Elex)

Sri S. K. Das, Senior Manager (Com-Tech)

ASMGCS

Sri Amal Chandra Biswas, Senior Manager (Com-Tech)

RADAR

Sri Shankar Bhattacharya, Assistant General Manager (CNS)

ADS

Sri Partha Pratim Sen, Senior Manager (Com-Tech)

Sri Partha Roy, Manager (Com-Tech)

Receiving Station

Sri P. K. Gangopadhyay, Assistant General Manager (Com-Tech)

VHF

Sri Amal Kumar Das, Assistant General Manager (Com-Tech)

Sri Biswajit Das, Assistant General Manager (Com-Tech)

Theories

ILS Sri Sukdeb Das, Assistant General Manager (Elex)

DVOR Sri Sukdeb Das, Assistant General Manager (Elex)

DME Sri Sukdeb Das, Assistant General Manager (Elex)

RADAR Sri Sisir Kumar De, Joint Manager (CNS)

ASMGSC Sri Amal Chandra Biswas, Senior Manager (Com-Tech)


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Special Thanks

Besides the Officers of AAI, the training also gave me an opportunity to interact with an extremely bright bunch of

budding engineers from various colleges across the country. The cosmopolitan environment along with their keen interest in the

topics being discussed made the training a very enriching and informative experience. I am very thankful to the Airport Authority

of India for providing me such a wonderful and inspiring group. I would also like to express a special thanks to all my group

members who supported and inspired me throughout the training. I cherished your company.

Group Members:

1. Ms. Adrija Nag (Institute of Science & Technology, Chandrakona Town)2. Mr. Koustuva Sarkar (Academy of Technology, Hooghly)3. Mr. Debadeep Mukherjee (Supreme Knowledge Foundation, Hooghly)4. Mr. Soham Deb (S.R.M. University, Delhi)5. Ms. Sukanya Kundu (Meghnad Saha Institute of Technology, Kolkata)6. Mr. Subhajit Samanta (Vellore Institute of Technology, Vellore)7. Mr. Sourav Saha (Haldia Institute of Technology, Haldia)8. Mr. Manisankar Biswas (Intern at AAI, Kolkata)


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About- Airports Authority of India (AAI)

Fig: Emblem of the AAI.

Mission: ''To achieve highest standards of safety and quality in air traffic

services and airport management by providing state-of-the-art infrastructure for total customer satisfaction, contributing to economic growth and prosperity of the nation.''

Vision : ''To be a world-class organization providing leadership in air traffic services

and airport management & making India a major hub in Asia Pacific region by 2016''.

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. Sri V.P. Agrawal is the current chairman of theAAI.

AAI manages 125 airports, which include 11 International Airport, 08 Customs Airports, 81 Domestic Airports

and 27 Civil Enclaves at Defence airfields. AAI provides air navigation services over 2.8 million square nautical miles of

air space. During the year 2008- 09, AAI handled aircraft movement of 1306532 Nos. [International 270345 & Domestic

1036187], Passengers handled 44262137 Nos. [International 1047614 & Domestic 33785990] and the cargo handled

499418 tons [International 318242 & Domestic 181176].

1. Passenger Facilities

The main functions of AAI inter-alia include construction, modification & management of passenger terminals,

development & management of cargo terminals, development & maintenance of apron infrastructure including runways,

parallel taxiways, apron etc., Provision of Communication, Navigation and Surveillance which includes provision of DVOR

/ DME, ILS, ATC radars, visual aids etc., provision of air traffic services, provision of passenger facilities and related

amenities at its terminals thereby ensuring safe and secure operations of aircraft, passenger and cargo in the country.

2. Air Navigation Services

In tune with global approach to modernization of Air Navigation infrastructure for seamless navigation acrossstate and regional boundaries, AAI has been going ahead with its plans for transition to satellite based Communication,


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Navigation, Surveillance and Air Traffic Management. A number of co-operation agreements and memoranda of co-

operation have been signed with US Federal Aviation Administration, US Trade & Development Agency, European Union,

Air Services Australia and the French Government Co-operative Projects and Studies initiated to gain from their

experience. Through these activities more and more executives of AAI are being exposed to the latest technology,

modern practices & procedures being adopted to improve the overall performance of Airports and Air Navigation

Services. Induction of latest state-of-the-art equipment, both as replacement and old equipment and also as new

facilities to improve standards of safety of airports in the air is a continuous process. Adoptions of new and improved

procedure go hand in hand with induction of new equipment. Some of the major initiatives in this direction are

introduction of Reduced Vertical Separation Minima (RVSM) in India air space to increase airspace capacity and reduce

congestion in the air; implementation of GPS And Geo Augmented Navigation (GAGAN) jointly with ISRO which when put to

operation would be one of the four such systems in the world.

3. Security

The continuing security environment has brought into focus the need for strengthening security of vitalinstallations. There was thus an urgent need to revamp the security at airports not only to thwart any misadventure but

also to restore confidence of traveling public in the security of air travel as a whole, which was shaken after 9/11

tragedy. With this in view, a number of steps were taken including deployment of CISF for airport security, CCTV

surveillance system at sensitive airports, latest and state-of-the-art X-ray baggage inspection systems, premier

security & surveillance systems. Smart Cards for access control to vital installations at airports are also being

considered to supplement the efforts of security personnel at sensitive airports.

4. Aerodrome Facilities

In Airports Authority of India, the basic approach to planning of airport facilities has been adopted to createcapacity ahead of demand in our efforts. Towards implementation of this strategy, a number of projects for extension

and strengthening of runway, taxi track and aprons at different airports has been taken up. Extension of runway to 7500

ft. has been taken up to support operation for Airbus-320/Boeing 737-800 category of aircrafts at all airports.

5. HRD Training

A large pool of trained and highly skilled manpower is one of the major assets of Airports Authority of India.

Development and Technological enhancements and consequent refinement of operating standards and procedures, new

standards of safety and security and improvements in management techniques call for continuing training to update the

knowledge and skill of officers and staff. For this purpose AAI has a number of training establishments, viz. NIAMAR inDelhi, CATC in Allahabad, Fire Training Centres at Delhi & Kolkata for in-house training of its engineers, Air Traffic

Controllers, Rescue & Fire Fighting personnel etc. NIAMAR & CATC are members of ICAO TRAINER programme under which

they share Standard Training Packages (STP) from a central pool for imparting training on various subjects. Both CATC &

NIAMAR have also contributed a number of STPs to the Central pool under ICAO TRAINER programme. Foreign students

have also been participating in the training programme being conducted by these institution

6. IT Implementation

Information Technology holds the key to operational and managerial efficiency, transparency and employee

productivity. AAI initiated a programme to indoctrinate IT culture among its employees and this is most powerful tool to


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enhance efficiency in the organization. AAI website with domain namewww.airportsindia.org.in or www.aai.aero is a

popular website giving a host of information about the organization besides domestic and international flight information

of interest to the public in general and passengers in particular.

Functions of AAI

Fig: Steward guiding an aircraft after landing.

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.
http://www.airportsindia.org.in/public_notices/aaisite_test/main_new.jsphttp://www.aai.aero/http://www.aai.aero/http://www.airportsindia.org.in/public_notices/aaisite_test/main_new.jsp


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AMSS-Automatic Message Switching System

Introduction

The 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:

- System- Switching- Messages-

Automation

1. System: AMSS is a dual architecture computer based system which consists of few servers and workstations which arelinked to each other over a local area network as well as other equipment/devices for data communication.

2. Messages: AMSS is mainly for exchange of AFTN messages, but at the same time AMSS can handle some non-AFTN messageslike AMS messages (formally known as HFRT/Radio messages).

3. Switching: AMSS receives the messages from the terminals connected via other switches, and after analyzing, stores themessages 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:

a. Line Switchingb. Message Switchingc. Packet Switching

4. Automation: So far as automation is considered for any system, it could be achieved by means of mechanical devices likerelay etc. and/or application software design as per requirement. In Electronics 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:

- Core System- Recording System- Users Terminal


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1. Core System: It incorporates communication adapters, protocols/suites, routing and gateway facilities. The coresystem is composed of two identical computer machines (known as AMSS main servers) which run in an

operational/hot standby combination. Both units supervise each others software and hardware. In case of

software/hardware failure of the operational unit, the hot standby unit is activated automatically so that it can take

over immediately without loss of data. The core system also includes remote communication adaptors, multiplexers and

one/two computer(s), known as communication servers, to avail the communication gateway facilities (if any).

2. Recording System: It has two identical mass data storage devices for storing of all incoming and outgoing AFTNmessages. 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. Users Terminals: It is the interface between user and the system with capability for uniform administration andmonitoring 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.


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Other information:

The Ethernet port is known as RJ-45. (Register Jack-45) The serial port which uses RS-232 protocol and is used to connect printers to computers can be used to

connect two computers and exchange data.

Switches work on the physical address and Routers work on IP addresses. To reach a particular user in a LAN network Media Access Control (MAC) address is required, this cannot be

achieved using IP address.

Length of IP address- 32 bits and MAC address is 48 bits.


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MLLN- Managed Leased Line Network Windows NT or Windows XP Operating System (OS) is used at Work Stations and Unix based OS is used for the

Server.

All software are provided by ECIL and software used at Server end is called Backend Software and is writtenin C language whereas software used at Work Station end is called Frontend Software and is written in Visual

C.

There are 4 layers in TCP/IP protocol stack as compared to 7 layers in OSI model. The layers are shownbelow:

In TCP/IP protocol there is no error checking in Internet layer but in X.25 protocol there is error checking inthe Internet layer. This makes X.25 very efficient and robust but makes it slow which is the reason it is

getting obsolete. Difference between Switch and HUB: In a HUB a message is broadcast with its MAC address and is

transmitted to all the receiving ports and collisions occur. In a Switch the MAC address is matched with the

PC name and sent only to that particular port, thus reducing collision.

In Dual Architecture the storage device (hard-disk) is connected using Daisy Chain connectivity. In suchsystems SCSI platform hard-disks are used.


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Comm. Briefing

The main function of this department is to approve the flight plans registered by all the aircrafts before take-off. Other

functions include checking and correcting flight routes mentioned on the flight plan. NOTAM messages are received and approved

from this department, and the corresponding officials are responsible for conveying these NOTAM messages to the pilotsbeforehand.

Flight Plan (FPL)

Fig: A typical Flight Plan form.

The figure above shows the International Flight Plan registration form. Any form of aircraft, be it commercial, defense,

or private, has to file a flight plan to the ATC almost 24 hours and at least 2 hours before flight take-off. Daily flights have their


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flight plan information uploaded on the system database and these are generated automatically every day at the scheduled time.

The Airport Authority of India has launched a new website for online filing of flight plans. The concerned authorities responsible

for the flight now can register their flight plans directly from anywhere, anytime.

The main information provided in the flight plan is as follows:

1. 7 letter Aircraft Identification Code2. Flight Rules - I (IFR), V (VFR) or Y (Both)3. Type of Flight N (Non Scheduled), S (Scheduled) or M (Military)4. Number Denotes number of aircraft (1 for normal flights, more for formation flights)5. Type of Aircraft Boeing (B737), Airbus (A320, A380), ATR flights (AT72), etc.6. Wake/Turbulence Category L (Light, less than 7000Kg), M(Medium, 7000-136000Kg) or H(Heavy, greater than

136000Kg)

7. Equipment N (NDB), V (DVOR), I (ILS), etc.8. Departure Aerodrome (4 letter A irport Identification Code)9. Time Time of departure in GMT10. Cruising Speed (expressed in Nautical Miles per hour)11. Level Denotes flight level or the altitude12. Route The full route from source to destination, via all the major airports13. Destination Aerodrome (4 letter Airport Identification Code)14. Estimated time to reach destination aerodrome15. 1st alternate aerodrome16. 2nd alternate aerodrome

Some other important information is also filled up, but it is flight specific and relays miscellaneous information about

the aircraft. This flight plan is checked and verified by Comm. Briefing department and then the aircraft becomes authorized totake-off.

NOTAM

NOTAM is the quasi-acronym for "Notices To Airmen". NOTAMs are created and transmitted by government agencies

and airport operators under guidelines specified by Annex 15: Aeronautical Information Services of the Convention on

International Civil Aviation (CICA). The term NOTAM came into common use rather than the more formal Notice to

Airmen following the ratification of the CICA, which came into effect on 4th April 1947. Notices to Airmen were normally published

in a regular publication (for example: Flight Magazine in the UK) by each country's air authorities. A number of developments andamendments to the CICA have resulted in the more automated system available today.

A NOTAM is filed with an aviation authority to alert aircraft pilots of any hazards en routeor at a specific location. The

authority in turn provides a means of disseminating relevant NOTAMs to pilots.

NOTAMs are issued (and reported) for a number of reasons, such as:

1. Hazards such as air-shows, parachute jumps, kite flying, rocket launches, etc.2. flights by important people such as heads of state (sometimes referred to as Temporary Flight Restrictions, TFRs)3. closed runways4. inoperable radio navigational aids5. military exercises with resulting airspace restrictions


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6. inoperable lights on tall obstructions7. temporary erection of obstacles near airfields (e.g. cranes)8. passage of flocks of birds through airspace (a NOTAM in this category is known as a BIRDTAM)9. notifications of runway/taxiway/apron status with respect to snow, ice and standing water (a SNOWTAM)10. notification of an operationally significant change in volcanic ash or other dust contamination (an ASHTAM)11. software code risk announcements with associated patches to reduce specific vulnerabilities

Aviation authorities typically exchange NOTAMs over AFTN circuits.

Software is available to allow pilots to identify NOTAMs near their intended route or at the intended destination.

The following describes International Civil Aviation Organization (ICAO) NOTAMs:-

The first line contains NOTAM identification (series, sequence number and year of issue), the type of operation (NEW,

REPLACE, CANCEL), as well as a reference to a previously-issued NOTAM (for NOTAMR and NOTAMC only).

The 'Q' line holds (basic-remove) information about who the NOTAM affects along with a basic NOTAM description. This

line can be encoded/decoded from tables defined by ICAO.

The 'A' line is the ICAO code of the affected aerodrome or FIR for the NOTAM. The area of influence of the NOTAM can be

several hundreds of kilometers away from the originating aerodrome.

The 'B' line contains the start time and date, the 'C' line the finish time and date of the NOTAM. The date is in the format

YY/MM/DD and the times are given in Universal Co-ordinated Time; also known as GMT or Zulu time.

Sometimes a 'D' line may be present. This gives a miscellaneous diurnal time for the NOTAM if the hours of effect are

less than 24 hours a day. E.g. parachute dropping exercises tend to occur for short periods of a few hours during the day, but

may be repeated over many days.

The 'E' line is the full NOTAM description. It is in English but heavily abbreviated. These abbreviations can be

encoded/decoded by tables defined by ICAO.

When present, 'F' and 'G' lines detail the height restrictions of the NOTAM. Typically SFC means surface height or ground

level and UNL is unlimited height. Other heights are given in feet or flight level or a combination of the two.

Example:

This is a typical NOTAM for London Heathrow airport:

A1234/06 NOTAMR A1212/06

Q)EGTT/QMXLC/IV/NBO/A/000/999/5129N00028W005

A)EGLL

B)0609050500

C)0704300500

E) DUE WIP TWY B SOUTH CLSD BTN 'F' AND 'R'. TWY 'R' CLSD BTN 'A' AND 'B' AND DIVERTED VIA NEW GREEN CL AND BLUE EDGE LGT.

ADZ CTN

This decodes into the following:

SERIES and NUMBER: A1234 issued in 2006

NATURE OF THE NOTAM : Replacing NOTAM 1212 issued in 2006
http://en.wikipedia.org/wiki/GMThttp://en.wikipedia.org/wiki/GMT


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FIR: EGTT (LONDON FIR)

SUBJECT: Taxiway (MX)

CONDITION: Closed (LC)

TRAFFIC: NOTAM issued for IFR (I) flights and VFR flights (V)

PURPOSE: NOTAM selected for immediate attention of aircraft operators (N)

PURPOSE: NOTAM selected for PIB entry (B)

PURPOSE: NOTAM Concerning Flight operations (O)

SCOPE: Aerodrome

GEOGRAPHICAL LOCATION: 5129' N 000 28' W

OPERATIONAL RADIUS OF THE NOTAM : 5 NM

AERODROME: London Heathrow (EGLL)

FROM: 05:00 UTC 5 September 2006

UNTIL: 05:00 UTC 30 April 2007

CATEGORY: Aerodromes, Air Routes and Ground Aids

DESCRIPTION: Due to work in progress, Taxiway 'B South' is closed between 'F' AND 'R'. Taxiway 'R' is closed between 'A' and 'B' and

is diverted via a new green center line and blue edge lighting. Advise caution.

Other information:

Skopograph is the device used to measure the visibility on a runway. 1 Nautical mile = 1.852 km RESA- Runway End Safety Area is the extra area provided at the end of runways to accommodate for

overshoot.

Flight Calibration: A flight is provided by AAI to help tune equipment at airports periodically, ILS is closedduring this operation and a NOTAM has to be issued.

Danger Areas: There are about 30 areas around Kolkata which may be classified as Danger Areas. If anydisturbing activities are observed in these regions, a NOTAM is issued.

Aeronautical Information Publication is a book published by AAI and Flight Operating Agencies use it forgathering various information relevant to navigation of flights, including sunrise and sunset timings of various

destinations.

Watch hour is the time of the day for which the airport is operational. For Patna it is 7am to 9pm. Declared distances


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TORA Takeoff Run Available The length of runway declared available and suitable for the ground run of an

airplane taking off.

TODA Takeoff Distance Available The length of the takeoff run available plus the length of the clearway, if

clearway is provided.ASDA Accelerate-Stop Distance Available The length of the takeoff run available plus the length of the

stopway, if stopway is provided

LDA Landing Distance Available The length of runway that is declared available and suitable for the ground

run of an airplane landing.

EDA Emergency Distance Available LDA (or TORA) plus a stopway.


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HFRT Communication

(Frequency range 3-30 MHz)

HFRT communication is the acronym for High Frequency Radio Telephony communication. When an aircraft crosses

200 NM radius from the aerodrome, one of the ways of communication is HFRT communication. HFRT is distant communication.

Unlike VHF frequency, it is not dependent on line of sight and it uses sky waves. Hence distant communication is possible through

HFRT. Mainly this is used for oceanic region where there is no way of communicating in VHF frequency range.

HFRT communication takes place between the pilot and the ATC officials to provide position report, estimate,

meteorological, flight level clearance, etc. by the aircraft.

This is operated in two modes:

1. MWARA Major World Air Route AreaThis is used for international flights. The available frequencies for MWARA at Netaji Subhash Chandra Bose International

airport at Kolkata are

a. 10066 KHzb. 6556 KHzc. 3491 KHzd. 2947 KHzAmong these, the 1st two are used during the day (1 is main, 1 is standby), and the other two at night.

2. RDARA Regional Domestic Air Route AreaThis is used for domestic flights. The available frequencies for RDARA at Netaji Subhash Chandra Bose Internationalairport at Kolkata are

a. 8869 KHzb. 6583 KHzc. 8948 KHzd. 5580 KHze. 2872 KHzThese are also operated in the same manner as those that of MWARA.

En-route VHF frequency for Kolkata HFRT is 127.3 MHz

Other information:

HFRT is very noisy because transmission is done using Ionospheric reflection. Imaginary points on different routes are named to facilitate the aircrafts navigation. Some names are: DOPID,

BBKO, MABUR, BINDA etc.

The difference in elevation levels that can be assigned to flights in the same direction is 1000 ft and in theopposite direction is 2000 ft.


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The minimum horizontal separation between two aircrafts is 10 NM. Skip distance: The minimum distance from a Transmitter, at which reception is received after reflection from

the ionosphere,

The microwave antennas on Mobile towers use VHF line of sight communication.

Fig: Showing HF Multi-hop propagation


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Remote Transmitting and Receiving Stations

Fig: Showing signal flow path in HFRT communication.

Local interference is removed if the Transmission and Receiving stations are located away from each other. Also by locating the

Transmitter (Tx) and Receiver (Rx) at a distance, a minimum skip distance is maintained between the Rx and Tx so that signal sentby Ionospheric propagation is received at the Rx.

Communication Center

(HFRT) at Terminal

Remote HF Receiving

Station (Badu)

Remote HF

Transmitting Station

(Garui)

Via UHF Link Via UHF Link


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HF Transmitter

Zenital CST-2002A is the transmitter which is used at the transmitting station located at Garui. The highest power that can be

transmitted from this transmitter is 2.5KW. (For VHF transmitter the highest power is around 50-100 W because the distance to

be covered in VHF is very small.) The antenna used is dipole antenna log-periodic in nature.

HF transmission mainly uses Ionospheric reflection as discussed earlier.

The transmitter consists of the following blocks (in order) as shown:

1. DFS2. Driver 1 Supply Voltlage=24V DC Maximum Gain=26 dB Class A Amplifier3. Driver 2- Supply Voltlage=48V DC Maximum Gain=17 dB Class A Amplifier4. Power Amplifier (PA)- Supply Voltlage=48V DC Maximum Gain=13.5 dB Class AB Amplifier5. Refectometer 1- Reflection coefficient is measured here.6. Filter- To eliminate the harmonics which have been introduced in the amplifier stages.7. Reflectometer 28. Matching Unit- Impedance matching for Maximum Power Transfer9. Balum Conversion from balanced to unbalanced line.10. Antenna

Here, the transmitter uses a Digital Frequency Synthesizer (DFS) to generate the carrier frequency instead of an oscillator. This

DFS uses DDS technology. Direct Digital Synthesizer (DDS) is a type of frequency synthesizer used for creating arbitrary

waveforms from a single, fixed-frequency reference clock. Applications of DDS include: signal generation, local oscillators in

communication systems, function generators, mixers, modulators, sound synthesizers and as part of a digital phase-locked loop.

Driver1 Driver2 Power

Amplifier

Reflecto

meter 1

Filter

DFS

Reflecto

meter2

Matching

Unit

Balum

Audio PTT


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Fig: Direct Digital Synthesizer block diagram

A basic Direct Digital Synthesizer consists of a frequency reference (often a crystal or SAW oscillator), a numerically controlled

oscillator (NCO) and a digital-to-analog converter (DAC) as shown in Figure 1.

The reference provides a stable time base for the system and determines the frequency accuracy of the DDS. It provides the

clock to the NCO which produces at its output a discrete-time, quantized version of the desired output waveform (often a

sinusoid) whose period is controlled by the digital word contained in the Frequency Control Register. The sampled, digital

waveform is converted to an analog waveform by the DAC. The output reconstruction filter rejects the spectral replicas produced

by the zero-order hold inherent in the analog conversion process.

A DDS has many advantages over its analog counterpart, the phase-locked loop (PLL), including much better frequency agility,improved phase noise, and precise control of the output phase across frequency switching transitions. Disadvantages include

spurious due mainly to truncation effects in the NCO, crossing spurious resulting from high order (>1) Nyquist images, and a

higher noise floor at large frequency offsets due mainly to the Digital-to-analog converter.

The transmitter also has a Transmitter Control System which is the decision making body of the transmitter. It consists of

WEBLINK, ADAMs and SIMPA. The WEBLINK is the CPU of the system. ADAMs are data acquisition modules which collect data and

send it to WEBLINK. SIMPA is the controller of the motor which changes the capacitor plate gap and varies the frequency to be

generated,

Yagi-Uda antenna is used to transmit from transmitter station to ATC at airport using line of sight communication.


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HF Receiver

ICOM Receiver (made in Japan) is used here. It is a wideband receiver. Its features are as follows:

1. Freq. coverage 100 KHz to 1999.9 MHz.2. It is a multipurpose receiver with different modes-

USB LSB CW FSK AM FM Wide FM

3. Receiver Type- Super heterodyne System4. Sensitivity- 2V (minimum amplitude at which receiver works)5. Audio output power 2.5 W6. Audio output impedance 4-8 ohms7. Power Supply for DC 13.8V and 220-240V for AC8. Antenna impedance (unbalanced) 50ohms9. Power Consumption < 110 VA10. Frequency Stability in 100KHz-30MHz (HF band) is 25Hz11. Number of memory channels 1000, broken into slots of 10012. Receiver uses Squelch system. In telecommunications, squelch is a circuit function that acts to suppress the audio (or

video) output of a receiver in the absence of a sufficiently strong desired input signal.

Fig: Basic Super heterodyne Receiver block diagram


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Valid dual pulse signal

DME (Frequency range 962-1215 MHz)

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. DME is similar to secondary radar, except in reverse.

The system was a post-war development of the IFF (identification friend or foe) systems of World War II.

Aircrafts use DME to determine their distance from a land-based transponder by sending and receiving pulse pairs. 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 also be co-located with an ILS glide

slope 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.

The operation is performed by sending and receiving two pulses of fixed duration and separation. The two pulses are

known as interrogation pulse and reply pulse. The first one is sent by the pilot to ground station, and the second one is replied

back to the pilot. The aircraft interrogates the ground transponder with a series of pulse-pairs (interrogations). The groundstation responds after a precise time delay, called the threshold time. The threshold time for India is 50s. If the processing time

is less than 50s, a delay counter delays the operational time to the threshold time. The ground station replies with an identical

sequence of reply pulse-pairs. To differentiate one aircrafts signal from other, special coding is applied for the signal. Each

aircraft has its own coding format. The reply signal is sent using the same coding.

The very first process that takes place after interrogation is pulse verification. To differentiate between a valid signal

and other signals this pulse verification process is necessary. A valid signal is recognized by its duration. A valid signal has pulse

duration of 12s and has only two pulses.

The permissible frequency range is 962-1215 MHz. Different airports select their transmitting and frequencies among

this range. The constraint is that the difference between the receiving and transmitting frequencies must be 63 MHz. For Kolkata,

the frequencies are 1159 MHz and 1096 MHz.

A radio pulse takes around 12.36 microseconds to travel 1 nautical mile (1,852 m) to and from; this is also referred to as

a radar-mile. The time difference between interrogation and reply 1 nautical mile (1,852 m) minus the 50 microsecond ground

transponder delay is measured by the interrogator's timing circuitry and translated into a distance measurement (slant range),

stated in nautical miles, and then displayed on the cockpit DME display.

The distance formula, distance = rate * time, is used by the DME receiver to calculate its distance from the DME ground

station. The rate in the calculation is the velocity of the radio pulse, which is the speed of light (roughly 300,000,000 m/s or

186,000 mi/s). The time in the calculation is (total time - 50s)/2.

A typical DME transponder can provide distance information to 100 aircraft at a time. Above this limit the transponder

avoids overload by limiting the gain of the receiver. Replies to weaker more distant interrogations are ignored to lower thetransponder load. The technical term for overload of a DME station caused by large numbers of aircraft is station saturation.

12 s


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The accuracy of DME ground stations is 185 m (0.1 NMI). It's important to understand that DME provides the physical

distance from the aircraft to the DME transponder. This distance is often referred to as 'slant range' and depends

trigonometrically upon both the altitude above the transponder and the ground distance from it. For example, an aircraft directly

above the DME station at 6076 ft. (1 NMI) altitude would still show 1.0 NMI (1.9 km) on the DME readout. The aircraft is technically a

mile away, just a mile straight up. Slant range error is most pronounced at high altitudes when close to the DME station.

ICAO recommends accuracy of 0.25 NMI plus 1.25% of the distance measured.


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DVOR


Navigation is the guidance of aircraft from one place to another. The equipment and support received by an aircraftstarting from the take-off at departing aerodrome to touchdown point at destination is known as Navigational Aids or Nav-Aids.

Various Nav-Aids are available like DVOR, DME, ILS, etc.

In the earlier times, there was no facility for so many scientific equipment. The only Nav-Aid available was Visual aid.

Direction of travel was determined by measuring deviations from the Pole Star or certain pre-determined landmarks. A little

development in science produced a more accurate and precise device called the Compass. This was relied upon for centuries

until modern science evolved and brought rapid changes to Nav-Aids. Now DVOR is used for identifying exact location.

VOR, short for VHF omnidirectional radio range , is a type of short-range radio navigation system for aircraft,

enabling aircraft to determine their position and stay on course by receiving radio signals transmitted by a network of fixed

ground radio beacons, with a receiver unit. It uses radio frequencies in the very high frequency (VHF) band from 112 to 118 MHz.Developed in the US beginning in 1937 and deployed by 1946, VOR is the standard air navigational system in the world, used by both

commercial and general aviation. There are about 3000 VOR stations around the world and 87 alone in all over India.

A VOR ground station sends out a master signal, and a highly directional second signal that varies in phase 30 times a

second compared to the master. This signal is timed so that the phase varies as the secondary antenna spins, such that when the

antenna is 90 degrees from north, the signal is 90 degrees out of phase of the master. By comparing the phase of the secondary

signal to the master, the angle (relative bearing) to the station can be determined. This bearing is then displayed in the cockpit of

the aircraft, and can be used to take a fix, although it is, in theory, easier to use and more accurate. This line of position is called

the "radial" from the VOR. The intersection of two radials from different VOR stations on a chart provides the position of the

aircraft. VOR stations are fairly short range; the signals have a range of about 200 miles.

DVOR or Doppler VOR is much more accurate than VOR as it reduces radial error to much more extent. It works by

radiating two low frequency signals:

Reference signal maintains same phase throughout the azimuth- frequency fc Variable signal varies its phase according to the azimuth- frequency fc9960The phase angle comparison of both the reference and variable signals gives the pilot the exact radial angle.

North is taken as reference, or it is assigned as 0.

Fig: Showing central omnidirectional antenna and surrounding 48 antennas.


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Non-Directional Beacons

(Frequency range 190-535 KHz)

A non-directional (radio) beacon (NDB) is a radio transmitter at a known location, used as an aviation or marinenavigational aid. As the name implies, the signal transmitted does not include inherent directional information, in

contrast to other navigational aids such as low frequency radio range, VHF omnidirectional range (VOR) and TACAN.

NDB signals follow the curvature of the earth, so they can be received at much greater distances at lower altitudes, a

major advantage over VOR. However, NDB signals are also affected more by atmospheric conditions, mountainous

terrain, coastal refraction and electrical storms, particularly at long range.

NDBs used for aviation are standardized by ICAO Annex 10 which specifies that NDBs be operated on a frequency

between 190 kHz and 1750 kHz, although normally all NDBs in North America operate between 190 kHz and 535 kHz.

Each NDB is identified by a one, two, or three-letter Morse code callsign North American NDBs are categorized by

power output, with low power rated at less than 50 watts, medium from 50 W to 2,000 W and high being over 2,000 W.

A bearing is a line passing through the station that points in a specific direction, such as 270 degrees (due West). NDB

bearings provide a charted, consistent method for defining paths aircraft can fly. In this fashion, NDBs can, like VORs,

define "airways" in the sky. Aircraft follow these pre-defined routes to complete a flight plan. Airways are numbered

and standardized on charts; colored airways are used for low to medium frequency stations like the NDB and are

charted in brown on sectional charts. Green and red airways are plotted east and west while amber and blue airways

are plotted north and south. While most airways in the United States are based on VORs, NDB airways are common

elsewhere, especially in the developing world like India and in lightly populated areas of developed countries, like the

Canadian Arctic, since they can have a long range and are much less expensive to operate than VORs.

Other information:

NDBs operate in Medium frequency range. NDB provides magnetic bearing and DVOR provides relative bearing. Bearing is always measured from Magnetic North. True North is fixed and magnetic North varies, In India variation is about 2-6 degrees.


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ILS

(Frequency range: Markers 75 MHz, Localizer 108-112 MHz, Glide Path 328-336 MHz)

An instrument landing system or ILS is a ground-based instrument approach system that provides precision

guidance to an aircraft approaching and landing on a runway, using a combination of radio signals and, in many cases, high-

intensity lighting arrays to enable a safe landing during instrument meteorological conditions (IMC), such as low ceilings or

reduced visibility due to fog, rain, or blowing snow.

Instrument approach procedure charts (or approach plates) are published for each ILS approach, providing pilots with

the needed information to fly an ILS approach during instrument flight rules (IFR) operations, including the radio frequencies used

by the ILS components or Nav-Aids and the minimum visibility requirements prescribed for the specific approach.

Radio-navigation aids must keep a certain degree of accuracy (set by international standards of ICAO); to assure this is

the case, flight inspection organizations periodically check critical parameters with properly equipped aircraft to calibrate and

certify ILS precision.

An ILS consists of two independent sub-systems, one providing lateral guidance (localizer), the other vertical guidance

(glide slope or glide path) to aircraft approaching a runway. Aircraft guidance is provided by the ILS receivers in the aircraft by

performing a modulation depth comparison.

A localizer (or LLZ) antenna array is normally

located beyond the departure end of the runway and generally

consists of several pairs of directional antennas. Two signals

are transmitted on one out of 40 ILS channels in the carrier

frequency range between 108.10 MHz and 111.95 MHz (with the

100 kHz first decimal digit always odd, so 108.10, 108.15, 108.30,

and so on are LLZ frequencies but 108.20, 108.25, 108.40, andso on are not). One is modulated at 90 Hz, the other at 150 Hz

and these are transmitted from separate but co-located

antennas. Each antenna transmits a narrow beam, one slightly

to the left of the runway centerline, the other to the right.

A glide slope (GS) or glide path (GP) antenna array is sited to

one side of the runway touchdown zone. The GP signal is

transmitted on a carrier frequency between 328.6 and

335.4 MHz using a technique similar to that of the localizer.

The centerline of the glide slope signal is arranged to define a

glide slope of approximately 3 above horizontal (ground level). These signals are displayed on an indicator in the instrumentpanel. This instrument is generally called the omni-bearing indicator or Nav-Indicator. The pilot controls the aircraft so that the


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indications on the instrument (i.e., the course deviation indicator) remain centered on the display. This ensures the aircraft is

following the ILS centerline (i.e., it provides lateral guidance). Vertical guidance, shown on the instrument by the glideslope

indicator, aids the pilot in reaching the runway at the proper touchdown point. Many aircraft possess the ability to route signals

into the autopilot, allowing the approach to be flown automatically by the autopilot.

Fig: A Glideslope station

Localizer backcourse

Modern localizer antennas are highly directional. However, usage of older, less directional antennas allows a runway to

have a non-precision approach called a localizer backcourse. This lets aircraft land using the signal transmitted from the back of

the localizer array. A pilot may have to fly opposite the needle indication, due to reverse sensing.

Marker beacons

On some installations, marker beacons operating at a carrier frequency of 75 MHz are provided. When the transmission

from a marker beacon is received it activates an indicator on the pilot's instrument panel and the tone of the beacon is audible to

the pilot.

Outer marker

The outer marker is normally located 7.2 km (3.9 NM; 4.5 mi) from the threshold except that, where this distance is not

practical, the outer marker may be located between 6.5 to 11.1 km (3.5 to 6.0 NM; 4.0 to 6.9 mi) from the threshold.

Middle marker

The middle marker should be located so as to indicate, in low visibility conditions, the missed approach point, and the

point that visual contact with the runway is imminent, ideally at a distance of approximately 3,500 ft. (1,100 m) from the threshold.

Inner marker

The inner marker, when installed, shall be located so as to indicate in low visibility conditions the imminence of arrival

at the runway threshold. This is typically the position of an aircraft on the ILS as it reaches Category II minima, ideally at a

distance of approximately 1,000 ft. (300 m) from the threshold.

ILS Categories

There are three categories of ILS which support similarly named categories of operation. Information below is based

on ICAO.
http://en.wikipedia.org/wiki/File:EDDV-ILS_09R_Glideslope.jpg


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1. Category I (CAT I) A precision instrument approach and landing with a decision height not lower than 200 feet (61 m)above touchdown zone elevation and with either a visibility not less than 800 meters or 2400 ft. or a runway visual

range not less than 550 meters (1,800 ft.) on a runway with touchdown zone and runway centerline lighting.

2. Category II (CAT II) A precision instrument approach and landing with a decision height lower than 200 feet (61 m)above touchdown zone elevation but not lower than 100 feet (30 m), and a runway visual range not less than 350meters (1,150 ft.).

3. Category III (CAT III) is subdivided into three sections:a. Category III A A precision instrument approach and landing with:

i) a decision height lower than 100 feet (30 m) above touchdown zone elevation, or no decisionheight (alert height); and

ii) a runway visual range not less than 200 meters (660 ft.).b. Category III B A precision instrument approach and landing with:

i) a decision height lower than 50 feet (15 m) above touchdown zone elevation, or no decision height(alert height); and

ii) a runway visual range less than 200 meters (660 ft.) but not less than 50 meters (160 ft. ).c. Category III C A precision instrument approach and landing with no decision height and no runway visual

range limitations. This category is not yet in operation anywhere in the world, as it requires guidance to taxi

in zero visibility as well. "Category III C" is not mentioned in EU-OPS. Category III B is currently the best

available system.

Fig: Showing Localizer on runway with 12 antennas.


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RADAR

(Frequency range MSSR L band (1030 MHz and 1090 MHz) ASR S band (2.7- 2.9 MHz))

Fig: An ASR (below) co-located with an MSSR (above)

Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of

objects. Radar stands for RAdio Detection And Ranging. It can be used to detect aircraft, ships, spacecraft, guided

missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio waves ormicrowaves which bounce off any object in their path. The object returns a tiny part of the wave's energy to a dish or antenna

which is usually located at the same site as the transmitter.

Classification:-

Based on operation:

1. Primary Radar Co-operation of targets is not required for detection. It works on echo technology.2. Secondary Radar Active co-operation of targets is required for finding range and other details of target.

Based on waveform:

1. CW Radar can detect moving target and its velocity.2. CWFM Radar can detect range using FM signals.3. Pulsed Radar uses pulse modulated microwave signals for detecting range & velocity.

Based on services:

1. Search Radar also known as surveillance radar. Uses continuously rotating antenna. Covers large volume of space.2. Tracking Radar gives accurate angular position, range and radial velocity of targets with precision. If used for

tracking it must first be co-located with search radar for 1st acquiring the target.

Applications


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1. Air Traffic Control2. Aircraft Navigation3. Maritime Navigation4. Meteorological Applications5. Space Applications6. Military Applications7. Law Enforcement Applications

Radars used in ATC

1. Airport Surveillance Radar (ASR)2. Air Route Surveillance Radar (SSR)3. Airport Surface Movement Detection Equipment (ASDE)4. Precision Approach Radar (PAR)5. Monopulse Secondary Surveillance Radar (MSSR)

Maximum range of RADAR depends on:-

a. Peak transmission power (4th root)b. Minimum detectable signal (MDS)c. Antenna Gaind. Radar Cross Section of the targete. Atmospheric Attenuation

Primary Radar

Primary Radar works on the principle of reflection or echo. Primary radar antennae continuously send pulses in all

possible directions. When these pulses hit some moving or still objects, the pulse is reflected back to the antenna. Generally the

radar transmitter and receiver are located at the same located. The radar processes the information and confirms the presence

of an object. If the object is moving either closer or farther away, there is a slight change in the frequency of the radio waves,

caused by the Doppler effect.

Secondary Radar

Secondary radar works target specific.

An interrogation pulse is sent from the radar

transmitter. The target, on receiving the signal,replies back with another signal. The radar then


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processes the distance covered by the signal and the time taken for the operation and calculates the position of the target

accordingly.

One kind of secondary radar used by ATC is MSSR or Monopulse Secondary Surveillance Radar.

MSSR Interrogation

The interrogator transmits a pairof pulses at 1030 MHz.

Each pulse has the same duration,shape and amplitude.

Their spacing distinguishesvarious modes of interrogation.

P2 pulse is used for control.Transponder Reply

F1 and F2 are always present (framing pulses). The 12 binary data pulses in four groups of 3 bits: A,B,C,D. 4096 possible ID codes (Mode 3/A reply). Special codes: 7500=Hijack, 7600=Comm Fail, 7700=Emergency. 2048 permutations (D1 omitted) of altitude code (Mode C reply) indicating heights. SPI (Special Position Indicator) pulse is used upon request by ground control.

Differences between Primary & Secondary Radar

Primary

1. Co-operation of target not required2. High Power3. No Code/Altitude information4. No Saturation5. Can detect Weather6. Clutter Problem7. Any target

Secondary

1. Co-operation of target required2. Low Power3. Code & Altitude information available4. Subject to Saturation5. No Weather detection6. No Clutter7. Friendly Targets


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ASMGCS

ASMGCS stands for Advanced Surface Movement and Guidance Control System. This system is used for ground

surveillance and monitoring. ASMGCS covers a 5 NM radius. Its main function is to monitor all the flights arriving, departing and

all objects present on ground within the radius. The ASMGCS processes real time images, called videos. Thus, all moving objectson and around the runway are monitored through It is a system at airports having a surveillance infrastructure consisting of a

Non-Cooperative Surveillance (e.g. SMR, Microwave Sensors, Optical Sensors etc) and Cooperative Surveillance (e.g.

Multilateration systems). A-SMGCS has 4 levels,

Level 1: Surface guidance is provided by ground markings and naked eye. Level 2: Radars are used to control the parking and movement of aircraft by ATC. This can be viewed on a

monitor by ATC.

Level 3: Along with Level 2 implementations, the pilots can also view their positions and other information. Level 4: Inter-airport connection, i.e., surface movement of different airports can be seen from one airport.

ICAO Doc 9830 defines A-SMGCS as follows: Advanced surface movement guidance and control system (A-SMGCS). Asystem 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.

Inputs & Components

SMR Surface Movement RADAR (primary)

M-Lat Multilateration System (secondary)

At NSCBI Airport at Kolkata, there is in total two Primary radars and a Secondary radar which has twelve as receivers and amongthem two function as transmitter also. This is required because Multilateration technique is used here which requires several

receivers.

Multilateration is a navigation technique based on the measurement of the difference in distance to two or more stations at

known locations that broadcast signals at known times. Unlike measurements of absolute distance or angle, measuring the

difference in distance results in an infinite number of locations that satisfy the measurement. When these possible locations are

plotted, they form a hyperbolic curve. To locate the exact location along that curve, a second measurement is taken to a diff erent

pair of stations to produce a second curve, which intersects with the first. When the two are compared, a small number of

possible locations are revealed, producing a "fix".

Difference between Conventional Primary Radar and the Primary Radar used in ASMGCS:

1. Pulse Repetition Factor (PRF) is 1000 pulse/sec for a range of 60 NM in a Conventional Primary Radar and 8000pulse/sec for the Primary Radar used in ASMGCS for a range of 5 NM. This difference is because the distance covered

by a Conventional Primary Radar is very large and more time is required for the pulse to return. Only after reception of

a pulse can the next pulse be sent.

2. Energy projection is upwards in a Conventional Primary Radar and towards ground in Primary Radars used in ASMGCS.3. cosec2 technique is used in Conventional Primary Radar and inverse cosec2 technique in Primary Radars used in

ASMGCS.

Secondary Radars used in ASMGCS are different from Conventional Secondary Radar in that they implement Multilateration.


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FDPS Flight Data Plan System (the final server for ASMGCS)

RDPS Radar Data Plan System (takes feed from MSSR, rotation speed is slow, hence update data is also slow, but SMR has 60

RPM, hence update data is faster and monitoring is good)

Interrogating frequency is 1090 MHz and Reply frequency is 1030 MHz

Two unique identification codes are 6 digit mode-S address Hex Code and 4 digit SSR code

RRP Recording and Replay Processor

IP Interface Processor

CTP Central Track Processor

CMSP Control Monitoring System Processor

RDP Radar Display Processor

RSDP Radar Service Display Processor

Main radar site has two RSDPs. They take real time images, process them and then send to ASMGCS.


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ARINC Aeronautical Radio Inc.

SITA Society International Telecommunication Aeronautics

ATSU Air Traffic Services Unit

AFTN Aeronautical Fixed Telecom Network

Just like HFRT communication, ADS is used for areas beyond 256 NM, i.e. area beyond the range of area radar. It is

mainly used in oceanic region where VHF communication is impossible. The major advantage is the use of satellite communication

in ADS. Thus, there is no case of frequency jam, or there is no queue. Moreover, this is just like ordinary telecom communication,

as the main function of sending and receiving the signals from aircraft to Air Traffic Control and vice versa is done by service

providers like ARINC or SITA. Hence, communication is faster and much more reliable than HFRT communication.

It may happen that at a particular area, the position of an aircraft is located both by radar as well as by ADS. At that

time, the data from radar is given more precedence that data received from ADS as radar gives more accurate data.

The data received through ADS provides information about latitude, longitude, altitude and time.

Through ADS, another mode of communication is also possible, CPDLC or Controller Pilot Data Link Communication. This

is a non-voice mode of communication. In this mode, a data connection is established between the pilot and the controller and any

information is passed in the form of messages just like in an ordinary data connection.

There are two modes of ADS communication:

ADS-C ADS contact, point to point communication, data is sent only from pilot to controller or vice versa.

Information is automatically updated every 27 minutes, presently used.

ADS-B ADS broadcast, future ADS, one to many communication, updated information is broadcasted every 10-12

seconds


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VHF


Radio spectrum refers to the part of the electromagnetic spectrum corresponding to radio frequencies that is,frequencies lower than around 300 GHz (or, equivalently, wavelengths longer than about 1 mm). Different parts of the radio

spectrum are used for different radio transmission technologies and applications.

This radio spectrum is divided into many frequency bands based on frequency ranges. Some of them are

Band Name Abbr. Frequency Range

Low Frequency LF 30 300 kHz

Medium Frequency MF 300 3000 kHz

High Frequency HF 3 -30 MHz

Very High Frequency VHF 30 300 MHz

Ultra High Frequency UHF 300 3000 MHz

Very high frequency (VHF) is the radio frequency range from 30 MHz to 300 MHz. Common uses for VHF are FM

radio broadcast, television broadcast, land mobile stations (emergency, business, private use and military), long range data

communication with radio modems, amateur radio, marine communications, air traffic control communications and air navigation

systems (e.g. VOR, DME & ILS).It is a line of sight communication system; hence it is not so suitable for very long distancecommunication. In Airports Authority of India, VHF communication is mainly used in SMC, DVOR, DME, ILS, Approach control, Tower

Control and Area Control.

In the VHF band:

108-156 MHz Communication bando 118-137 MHz Aeronautical bando 137-156 MHz Upper Military band

Modes of VHF communication are as follows:

1. Broadcast and 2. Point to point

The VHF frequencies available at Kolkata airport are

118.1 MHz Tower

119.3 MHz Approach (standby)

119.5 MHz Monopulse Secondary Surveillance Radar (MSSR)

120.1 MHz Area Control (West)

120.7 MHz Area Control (East)


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121.5 MHz Distress (Emergency Frequency)

121.9 MHz Surface Movement Control (SMC)

125.9 MHz Area (East standby)

126.1 MHz Area (West standby)

126.4 MHz Digital Airport Terminal Information System (DATIS)

127.3 MHz Feeder

127.9 MHz Approach

132.45 Area (South)

Some important frequencies:

SMC, 121.9 MHz

Surface Movement Control, also known as Ground Control or Apron Control. Its job is to monitor and control aircrafts in

the apron. Provision for Follow Me Jeep is also available through SMC.

Tower, 118.1 MHz

Just when the aircraft reaches runway, SMC handovers control to Tower. Tower functions on both instrumental as well

as visual aids. All major international airports have the same SMC and Tower frequency. It covers a range of radius 10NM.

Approach, 127.9MHz (119.3 s/by)

After Tower, control is transferred to Approach Control. Approach Control has its own radar which has a fixed and a

standby frequency. Its range is 10NM 50NM.

Area Control

Area Control takes charge after 50NM. Its range is 50NM 250NM. Since the area of coverage is vast, it is nearly

impossible for a controller to monitor and control all of the aircrafts in this range. Hence, area is divided into 3 regions- East,

West & South.

Feeder, 127.3MHz

Feeder is also known as PBN or Performance Based Navigation system. When an aircraft establishes connection at

Feeder frequency, it is provided with GPS; hence no further aid is required.

DATIS, 126.4MHz

DATIS or Digital Airport Terminal Information System is always operated in broadcast mode. Every half an hour updated

information is broadcasted.

Emergency, 121.5MHz

This is emergency or distress frequency. When there is immediate need for aircraft to contact controller, this

frequency is used. This frequency is maintained worldwide.


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VHF Transmitter

Oscillator is required for generating frequency Synthesizer is required to generate a range of frequencies PLL is used for synthesizing

Receiver Properties

Sensitivity Ability to receive the weakest signal Selectivity Ability to reject the adjacent channel Fidelity Reproduction of quality

Formula for calculating total power:

Pt = Pc (1+m2/2)

where is Pt total power, Pc is carrier power, m is percentage of modulation

PLL for generating 120 MHz frequency

VHF AM Transmitter


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Other information:

Use of 1st IF (21.4 MHz) is image frequency rejection and use of 2nd IF (0.455 MHz) is adjacent channel rejection. In order to tune to 120.7 MHz, 1st LO freq. will be 120.7+21.4 MHz = 142.1 MHz, 2 nd LO freq. will always be 21.4+0.455 MHz =

21.855 MHz.

Straight dipole impedance is 70-72 ohms. Folded dipole impedance is 70*n2, where n is the number of folds. In VHF folded dipole with n=2 is used because its impedance is 70*4= 280 ohms and space impedance is also 300

ohms. This provides impedance matching.

In case of NDBs ground reflection is required, so straight dipole with 50 ohm impedance is used. Gain of dipole antenna is unity. In the receiver two dipoles are staged together to increase the gain by 3dB. The distance between the two dipoles is to

be maintained between 1 lambda to 0.7 lambda.

Dipole is mounted vertically because the polarization is vertical.

VHF AM Receiver


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Radio Propagation

Radio frequencies and their primary mode of propagation

Band Frequency Wavelength Propagation via

ELF Extremely Low

Frequency

3300 Hz 1000-100,000 km

VLF Very Low Frequency 330 kHz 10010 km Guided between the earth and the ionosphere.

LF Low Frequency 30300kHz 101 km Guided between the earth and the D layer of the

ionosphere and Surface waves.

MF Medium Frequency 300

3000kHz

1000100 m Surface waves and E, F layer ionospheric

refraction at night, when D layer absorptionweakens.

HF High Frequency (Short

Wave)

330 MHz 10010 m E layer ionospheric refraction. and F1, F2 layer

ionospheric refraction.

VHF Very High Frequency 30

300MHz

101 m Generally direct wave. Infrequent E ionospheric

refraction. Extremely rare F1,F2 layer

ionospheric refraction during high sunspot

activity up to 80 MHz. Sometimes tropospheric

ducting.

UHF Ultra High Frequency 300

3000MHz

10010 cm Direct wave. Sometimes tropospheric ducting.

SHF Super High Frequency 330 GHz 101 cm Direct wave.

EHF Extremely High

Frequency

30300GHz 101 mm Direct wave limited by absorption.

Surface modes

Lower frequencies (between 30 and 3,000 kHz) have the property of following the curvature of the earth

via groundwave propagation in the majority of occurrences.

In this mode the radio wave propagates by interacting with the semi-conductive surface of the earth. The wave "clings"

to the surface and thus follows the curvature of the earth. Vertical polarization is used to alleviate short circuiting the

electric field through the conductivity of the ground. Since the ground is not a perfect electrical conductor, ground

waves are attenuated rapidly as they follow the earths surface. Attenuation is proportional to the frequency making

this mode mainly useful for LF and VLF frequencies.
http://en.wikipedia.org/wiki/Extremely_low_frequencyhttp://en.wikipedia.org/wiki/Extremely_low_frequencyhttp://en.wikipedia.org/wiki/Hertzhttp://en.wikipedia.org/wiki/Very_low_frequencyhttp://en.wikipedia.org/wiki/Very_low_frequencyhttp://en.wikipedia.org/wiki/Kilohertzhttp://en.wikipedia.org/wiki/Ionospherehttp://en.wikipedia.org/wiki/Low_frequencyhttp://en.wikipedia.org/wiki/Low_frequencyhttp://en.wikipedia.org/wiki/Kilohertzhttp://en.wikipedia.org/wiki/D_layerhttp://en.wikipedia.org/wiki/Surface_wavehttp://en.wikipedia.org/wiki/Medium_frequencyhttp://en.wikipedia.org/wiki/Kilohertzhttp://en.wikipedia.org/wiki/F_layerhttp://en.wikipedia.org/wiki/High_frequencyhttp://en.wikipedia.org/wiki/High_frequencyhttp://en.wikipedia.org/wiki/Shortwavehttp://en.wikipedia.org/wiki/Shortwavehttp://en.wikipedia.org/wiki/Megahertzhttp://en.wikipedia.org/wiki/E_layerhttp://en.wikipedia.org/wiki/F2_propagationhttp://en.wikipedia.org/wiki/Very_high_frequencyhttp://en.wikipedia.org/wiki/Very_high_frequencyhttp://en.wikipedia.org/wiki/Megahertzhttp://en.wikipedia.org/wiki/Sporadic_E_propagationhttp://en.wikipedia.org/wiki/Sporadic_E_propagationhttp://en.wikipedia.org/wiki/F2_propagationhttp://en.wikipedia.org/wiki/Tropospheric_ductinghttp://en.wikipedia.org/wiki/Tropospheric_ductinghttp://en.wikipedia.org/wiki/Ultra_high_frequencyhttp://en.wikipedia.org/wiki/Ultra_high_frequencyhttp://en.wikipedia.org/wiki/Megahertzhttp://en.wikipedia.org/wiki/Line-of-sight_propagationhttp://en.wikipedia.org/wiki/Tropospheric_ductinghttp://en.wikipedia.org/wiki/Super_high_frequencyhttp://en.wikipedia.org/wiki/Super_high_frequencyhttp://en.wikipedia.org/wiki/Gigahertzhttp://en.wikipedia.org/wiki/Extremely_high_frequencyhttp://en.wikipedia.org/wiki/Extremely_high_frequencyhttp://en.wikipedia.org/wiki/Gigahertzhttp://en.wikipedia.org/wiki/Groundwavehttp://en.wikipedia.org/wiki/Polarization_(waves)http://en.wikipedia.org/wiki/Attenuationhttp://en.wikipedia.org/wiki/Low_frequencyhttp://en.wikipedia.org/wiki/VLFhttp://en.wikipedia.org/wiki/VLFhttp://en.wikipedia.org/wiki/Low_frequencyhttp://en.wikipedia.org/wiki/Attenuationhttp://en.wikipedia.org/wiki/Polarization_(waves)http://en.wikipedia.org/wiki/Groundwavehttp://en.wikipedia.org/wiki/Gigahertzhttp://en.wikipedia.org/wiki/Extremely_high_frequencyhttp://en.wikipedia.org/wiki/Gigahertzhttp://en.wikipedia.org/wiki/Super_high_frequencyhttp://en.wikipedia.org/wiki/Tropospheric_ductinghttp://en.wikipedia.org/wiki/Line-of-sight_propagationhttp://en.wikipedia.org/wiki/Megahertzhttp://en.wikipedia.org/wiki/Ultra_high_frequencyhttp://en.wikipedia.org/wiki/Tropospheric_ductinghttp://en.wikipedia.org/wiki/Tropospheric_ductinghttp://en.wikipedia.org/wiki/F2_propagationhttp://en.wikipedia.org/wiki/Sporadic_E_propagationhttp://en.wikipedia.org/wiki/Sporadic_E_propagationhttp://en.wikipedia.org/wiki/Megahertzhttp://en.wikipedia.org/wiki/Very_high_frequencyhttp://en.wikipedia.org/wiki/F2_propagationhttp://en.wikipedia.org/wiki/E_layerhttp://en.wikipedia.org/wiki/Megahertzhttp://en.wikipedia.org/wiki/Shortwavehttp://en.wikipedia.org/wiki/Shortwavehttp://en.wikipedia.org/wiki/High_frequencyhttp://en.wikipedia.org/wiki/F_layerhttp://en.wikipedia.org/wiki/Kilohertzhttp://en.wikipedia.org/wiki/Medium_frequencyhttp://en.wikipedia.org/wiki/Surface_wavehttp://en.wikipedia.org/wiki/D_layerhttp://en.wikipedia.org/wiki/Kilohertzhttp://en.wikipedia.org/wiki/Low_frequencyhttp://en.wikipedia.org/wiki/Ionospherehttp://en.wikipedia.org/wiki/Kilohertzhttp://en.wikipedia.org/wiki/Very_low_frequencyhttp://en.wikipedia.org/wiki/Hertzhttp://en.wikipedia.org/wiki/Extremely_low_frequency


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Today LF and VLF are mostly used for time signals, and for military communications, especially with ships and

submarines, although radio amateurs have an allocation at 137 KHz in some parts of the world.

Direct modes (line-of-sight)

Line-of-sight is the direct propagation of radio waves between antennas that are visible to each other. This is probablythe most common of the radio propagation modes at VHF and higher frequencies. Because radio signals can travel

through many non-metallic objects, radio can be picked up through walls. This is still line-of-sight propagation.

Examples would include propagation between a satellite and a ground antenna or reception of television signals from a

local TV transmitter. Ground plane reflection effects are an important factor in VHF line of sight propagation. The

interference between the direct beam line-of-sight and the ground reflected beam often leads to an effective inverse-

fourth-power i.e. (1/distance)^4 law for ground-plane limited radiation.

Ionospheric modes (skywave)

Skywave propagation, also referred to as skip, is any of the modes that rely on refraction of radio waves inthe ionosphere, which is made up of one or more ionized layers in the upper atmosphere. F2-layer is the most

important ionospheric layer for long-distance, multiple-hop HF propagation, though F1, E, and D-layers also play

significant roles. The D-layer, when present during sunlight periods, causes significant amount of signal loss, as does

the E-layer whose maximum usable frequency can rise to 4 MHz and above and thus block higher frequency signals

from reaching the F2-layer.
http://en.wikipedia.org/wiki/Time_signalhttp://en.wikipedia.org/wiki/Military_communicationshttp://en.wikipedia.org/wiki/Line-of-sight_propagationhttp://en.wikipedia.org/wiki/VHFhttp://en.wikipedia.org/wiki/Ground_planehttp://en.wikipedia.org/wiki/Reflection_(physics)http://en.wikipedia.org/wiki/Skywavehttp://en.wikipedia.org/wiki/Skip_(radio)http://en.wikipedia.org/wiki/Refractionhttp://en.wikipedia.org/wiki/Ionospherehttp://en.wikipedia.org/wiki/Earth%27s_atmospherehttp://en.wikipedia.org/wiki/Earth%27s_atmospherehttp://en.wikipedia.org/wiki/Ionospherehttp://en.wikipedia.org/wiki/Refractionhttp://en.wikipedia.org/wiki/Skip_(radio)http://en.wikipedia.org/wiki/Skywavehttp://en.wikipedia.org/wiki/Reflection_(physics)http://en.wikipedia.org/wiki/Ground_planehttp://en.wikipedia.org/wiki/VHFhttp://en.wikipedia.org/wiki/Line-of-sight_propagationhttp://en.wikipedia.org/wiki/Military_communicationshttp://en.wikipedia.org/wiki/Time_signal


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Runway Naming Convention

Fig: Showing runway naming. (Photograph taken from North direction.)

A runway designation consists of two numbers each of two digits, one number being the reciprocal of the other. (This

use of the term 'reciprocal' applies to navigation and compasses. It means the two numbers differ by 180.) Onenumber is formed by rounding the compass bearing of one end of the runway up or down to the nearest 10 and

dropping the last digit; if this results in a single digit, add a zero to the left of it. The other number is the reciprocal of

the first number (see the table of Reciprocal Runway Numbers below). If a runway is aligned north-south, then it is

18/36, not 00/18. The lower number is always listed f irst.

When pilots and air traffic controllers refer to a runway, they use only the number that applies to the end the pilot will

be landing on. Thus if the pilot is landing on Runway 09/27 heading to the east, they are using Runway 09, not Runway

27.

Examples:

If the compass heading of a runway is 122 you would round it down to 120 and drop the last digit, leaving you with 12.

Thus it is called Runway 12/30.

If the compass heading of a runway is 37, you would round it up to 40 and drop the last digit, leaving you with 4. Since

this is a single digit, you add a zero to the beginning, giving you 04. Thus it is called Runway 04/22.


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Reciprocal Runway Numbers

North/East end South/West end

01 19

02 20

03 21

04 22

05 23

06 24

07 25

08 26

09 27

10 28

11 29

12 30

13 31

14 32

15 33

16 34

17 35

18 36

At NSCBI Airport, Kolkata the runways used are 01L/19R and 01R/19L.


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VOLMET

VOLMET, or meteorological information for aircraft in flight, is a worldwide network of radio stations that

broadcast TAF, SIGMET and 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 these transmissions to avoid storms and 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 in each region broadcast

weather reports for specific groups of air terminals in their region at specific times, coordinating their transmission

schedules so as not to interfere with one another. Schedules are determined in intervals of five minutes, with one

VOLMET station in each region broadcasting reports for a fixed list of cities in each interval. These schedules repeat

every hour.
http://en.wikipedia.org/wiki/Radio_networkhttp://en.wikipedia.org/wiki/Terminal_Aerodrome_Forecasthttp://en.wikipedia.org/wiki/SIGMEThttp://en.wikipedia.org/wiki/METARhttp://en.wikipedia.org/wiki/Shortwavehttp://en.wikipedia.org/wiki/VHFhttp://en.wikipedia.org/wiki/Single-sideband_modulationhttp://en.wikipedia.org/wiki/North_Atlantic_Trackshttp://en.wikipedia.org/wiki/North_Atlantic_Trackshttp://en.wikipedia.org/wiki/Single-sideband_modulationhttp://en.wikipedia.org/wiki/VHFhttp://en.wikipedia.org/wiki/Shortwavehttp://en.wikipedia.org/wiki/METARhttp://en.wikipedia.org/wiki/SIGMEThttp://en.wikipedia.org/wiki/Terminal_Aerodrome_Forecasthttp://en.wikipedia.org/wiki/Radio_network


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Controller Pilot Data Link Communications

Controller Pilot Data Link Communications (CPDLC), also referred to as Controller Pilot Data Link (CPDL), is a method

by which air traffic controllers can communicate with pilots over a data link system.

Necessity

The standard method of communication between an air traffic controller and a pilot is voice radio, using

either VHF bands for line-of-sight communication or HF bands for long-distance communication (such as that provided

by Shanwick Oceanic Control).

One of the major problems with voice radio communications used in this manner is that all pilots being handled by a

particular controller are tuned to the same frequency. As the number of flights air traffic controllers must handle is

steadily increasing (for instance, Shanwick handled 391,273 flights in 2006, an increase of 5.4% - or 20,000 flights -

from 2005), the number of pilots tuned to a particular station also increases. This increases the chances that one pilot

will accidentally override another, thus requiring the transmission to be repeated. In addition, each exchange between

a controller and pilot requires a certain amount of time to complete; eventually, as the number of flights being

controlled reaches a saturation point, the controller will not be able to handle any further aircraft.

Traditionally, this problem has been countered by dividing a saturated Air Traffic Control sector into two smaller

sectors, each with its own controller and each using a different voice communications channel. However, this strategy

suffers from two problems:

Each sector division increases the amount of "handover traffic". That is the overhead involved in transferring aflight between sectors, which requires a voice exchange between the pilot and both controllers, plus co-ordination

between the controllers.

The number of available voice channels is finite, and, in high density airspace, such as central Europe or theEastern Seaboard of the USA, there may not be a new channel available.

In some cases it may not be possible or feasible to further divide down a section.

A new strategy is needed to cope with increased demands on Air Traffic Control, and data link based communications

offers a possible strategy by increasing the effective capacity of the communications channel.

Use of CPDLC
http://en.wikipedia.org/wiki/Air_traffic_controllerhttp://en.wikipedia.org/wiki/Datalinkhttp://en.wikipedia.org/wiki/Air_traffic_controllerhttp://en.wikipedia.org/wiki/Very_high_frequencyhttp://en.wikipedia.org/wiki/High_frequencyhttp://en.wikipedia.org/wiki/Shanwick_Oceanic_Controlhttp://en.wikipedia.org/wiki/Shanwick_Oceanic_Controlhttp://en.wikipedia.org/wiki/High_frequencyhttp://en.wikipedia.org/wiki/Very_high_frequencyhttp://en.wikipedia.org/wiki/Air_traffic_controllerhttp://en.wikipedia.org/wiki/Datalinkhttp://en.wikipedia.org/wiki/Air_traffic_controller


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Fig: The Datalink Control and Display Unit (DCDU) on an Airbus A330, the pilot interface for sending and receiving CPDLC messages.

Controller pilot data link communication (CPDLC) is a means of communication between controller and pilot, using data

link for ATC communication. At the highest level, the concept is simple, with the emphasis on the continued invo lvement

of the human at either end and the flexibility of use.

The CPDLC application provides air-ground data communication for the ATC service. This incl

utkarsh tiwari aai report

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