AAI project

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AIRPORTS AUTHORITY OF INDIA REGIONAL TRAINING CENTER (CNS),ER N.S.C.B.I AIRPORT,KOLKATA-700052 A Project Report On winter Vocational Training in- Communication, Navigation and Surveillance (CNS) Submitted By- AKASH CHOWDHURY Electronics & Communication Engineering - B.Tech – 3 rd Year of

Transcript of AAI project

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AIRPORTS AUTHORITY OF INDIA REGIONAL TRAINING CENTER

(CNS),ERN.S.C.B.I AIRPORT,KOLKATA-700052

A Project Report On winter Vocational Training in-

Communication, Navigation and Surveillance (CNS)

Submitted By-

AKASH CHOWDHURYElectronics & Communication Engineering - B.Tech – 3rd Year

of

HERITAGE INSTITUTE OF TECHNOLOGY

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CERTIFICATE

This is to certify that Akash Chowdhury, a student of 3rd year in Electronics and Communication Engineering (BTECH) from Heritage Institute of Technology, has completed his Winter Vocational Training on Communication Navigation and Surveillance (CNS) at Airports Authority of India, Regional Training Centre (CNS), Eastern Region, Netaji Subhash Chandra Bose International Airport, Kolkata from 4th January, 2016 to 15th January, 2016.

---------------------------------------------- Signature of Training Coordinator (Shri. Samir Kumar Mukhopadhyay)

Assistant General Manager (CNS)

Date:

Place: Kolkata

Remarks:

STUDENT'S DECLARATION

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I hereby declare that I, Shri. Akash Chowdhury has completed my winter vocational training on COMMUNICATION, NAVIGATION AND SURVEILLANCE (CNS) and submitted my project report to Regional Training Centre (CNS), Eastern Region, Airports Authority of India, NSCBI Airport, Kolkata on the completion of the same from 4th January to 15th January 2016.

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 of Student

Name of Student: AKASH CHOWDHURY

Place: Kolkata

Date:

CONTENTS

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Subject Page Nos.

Acknowledgement.................................................................... 01 Introduction.......................................................……...……......... 03 Functions of AAI........................................................................ 04 Introduction of CNS................................................................... 05 Communication……………………………………………………………………… 08 HF Communication..................................................................... 09 HF Transmitter………………………………………………………………………...11 HF Receiver………………………………………………………………………………15 VHF Communication…………………………………………………….....………17 VHF Transmitter………………………………………………………………………18 VHF Receiver……………………………………………………………………………20 AMSS........................................................................................ 21 AFTN……………………………………………………………………………………… 23 VOLMET................................................................................... 25 ADS.......................................................................................... 26 CPDLC....................................................................................... 28 HFRT………………………………………………………………………………………..29 SELCAL...................................................................................... 31 ASMGCS.................................................................................... 32 RADAR...................................................................................... 34 MSSR...........................…........................................................... 36 SMR........................................................................................... 38 AUTOMATION........................................................................... 39 MLAT……………………..……………………………………………..………………. 45 CMU…………..………………………………………………………………………….. 46 WEB BASED CONTROL............................................................... 48 NOTAM....................................................................................... 54

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NAV-AIDS.................................................................................. 56 Non Directional Beacons………………………………………………………….57 DVOR……………………………………………………………………………………….58 DME…………………………………………………………………………………………62 ILS…………………………………………………………………………………………….65 CONCLUSION………………………………………………………………..……… 74 BIBLIOGRAPHY…………………..………………………………………………… 75

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ACKNOWLEDGEMENTI take this opportunity to express my profound gratitude and deep regards to my guide Shri. S. Ghosh, General Manager (CNS) for their 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 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.

I am obliged to the 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.

RTC (CNS) ER

MR.Samir Kumar Mukhopadhyay, ASM(CNS)-RTC

MR.Santosh Kumar Sinha (CNS)-RTC

Theory classesMR.Sudip Bandapadhyay,AGM(CNS)-VHF

MR.Kamal Majumdar,AGM(CNS)-DME

MR.Pranab Bhattacharya,DGM(CNS)-ASMGCS

MR.Samit Kr. Das,AGM(CNS)-HF TRANSMITTER

MR.Ashok Datta,AGM(CNS)-RADIO

MR.S.K. Lahiri ,AGM(CNS)-CMU

MR.Uttam Sengupta ,AGM(CNS)-AMSS

MR.Arnab Bhattacharya, ,AGM(CNS)-ASMGCS

MR.Sambhu Ghosh,AGM(CNS)-RADAR

MR.Upal Debanth,AGM(CNS)-AUTOMATION

MR.Soumitra Chakraborty,AGM(CNS)-VHF TRANSMITTER

MR.Sumitabha Karmakar,AGM(CNS)-MSSR

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MR.Tapas Banerjee,AGM(CNS)-HF RECEIVER

MR.Gouri Shankar Ghosh,AGM(CNS)-COM BRIEFING

MR.Sekhar Acharya,Manager(CNS)-RADAR

MR.Karunamoy Pal,AGM(CNS)-MSSR

MR.Jainal Abedin,SM(CNS)-AUTOMATION

MR.S Bhandyopadhyay,DGM(CNS)-NAVAIDS

SPECIAL REGARDS

I take this opportunity to express my sincere gratitude to Prof. Dr.P.Banerjee, head of the Electronics and Communication Engineering Department, Heritage Institute of Technology, Kolkata, who gave the permission to be associated with one of the best organisation, Airports Authority of India, NSCBI Airport, Kolkata.

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INTRODUCTION

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 manages 133 airports and 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]. AAI provides CNS/ATM services at all the civil airports in the country.The 133 airports managed by AAI includes 16 international,8 custom,24 civil enclaves and 80 domestic airports.

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FUNCTIONS OF AAIThe functions of AAI are as follows:

Design, Development, Operation and Maintenance of international and domestic airports and civil enclaves.

Control and Management of the Indian airspace extending beyond the territorial limits of the country, as accepted by ICAO.

Construction, Modification and Management of passenger terminals.

Development and Management of cargo terminals at international and domestic airports.

Provision of passenger facilities and information system at the passenger terminals at airports.

Expansion and strengthening of operation area, viz. Runways, Aprons, Taxiway etc.

Provision of visual aids.

Provision of Communication and Navigation aids, viz. ILS, DVOR, DME, Radar etc.

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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 process of sending, processing & receiving of information by electrical means. In Radio communication, for the transmission information are first converted into electrical signals then modulated with a carrier signal of high frequency, amplified up to a required level, converted into electromagnetic waves & radiated in the space, with the help of antenna. For reception these electromagnetic waves are converted to electrical signals, amplified, detected & reproduced in the original form of information with the help of speaker. Communication is the exchange of voice and data information between the pilot and air traffic controllers or flight information centres.

Fig: Block diagram representing transmitter & receiver

Frequencies band uses in Communication:

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NAME OF THE EQUIPMENT

FREQUENCY BEND USES

NDB 200-450 KHz Locator, Homing & En-route.

HF 3-30 MHz Ground to Ground/Air Communication.

Localizer 108-112 MHz Instrument Landing System

VOR 108-117.975 MHz Terminal, Homing & En-route

VHF 117.975-137 MHz Ground to Air Communication

Glide Path 328-336 MHz Instrument Landing System

DME 960-1215 MHz Measurement of Distance

UHF LINK 0.3-2.7 GHz Remote control, Monitoring

RADAR 0.3-12 GHz Surveillance

Navigation:-

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Navigation Element of CNS/ATM Systems Is meant to provide Accurate, Reliable and Seamless Position Determination Capability to aircrafts.

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.

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Communication is the specialized field concerned with the use of electronic devices and systems for the acquisition or acceptance, processing, storage, display, analysis, protection, disposition, and transfer of information. A constant exchange of information is necessary between the aircraft and the base or Air Traffic Control centre. Communication systems consist of a number of components that facilitate processing of the information, its transmission and corresponding reception at the destination, and finally retrieval of the required message. With regards to the CNS system, communication can be classified as:

Voice communication – it involves sending audio messages Data communication – it involves sending messages in the form of texts

Voice communication is a direct form of communication and is hence a faster process than data communication which involves processing time (leading to time delay).

There are two allotted band of frequencies which are used in communication for aviation purpose. They are the High frequency (HF) band and the Very high frequency (VHF) band. The HF band ranges from 3-30 MHz while VHF band ranges from 30-300 MHzFor aviation purposes the preferred HF range is 3-12 MHz and for VHF the range between 118-136 MHz is preferred.

Transmission of information over free space takes place in the form of electromagnetic radiation or light (in case of optic fibres).

HF COMMUNICATIONHigh frequency (HF) radio provides aircraft with an effective means of communication over long distance oceanic and trans-polar routes. In addition, global data communication has recently been

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made possible using strategically located HF data link (HFDL) ground stations. HF communication is preferred in cases where VHF communication is not possible.

Characteristics of HF Communication:

HF follows Sky-wave propagation (involves total internal reflection of the HF signal in the ionosphere).

It is used mainly for long distance propagation beyond 200 nautical miles.

Bandwidth of HF Communication is in between 3MHz to 30 MHz, due to reflection from the ionised layers in the upper atmosphere. Due to variations in height and intensities of the ionised regions, different frequencies are used at different times of day and night and for different paths.

Polarisation is horizontal.

It has a wider range and is not affected by obstruction.

Between the transmitter and the receiver there is a considerable region of blind range, where no signal is available. This distance is known as skip distance (Disadvantages of Sky Wave Propagation).

HF communication does not have high noise immunity due to ionospheric interference.

HFRT is also used for ground to ground communication, although it being fast replaced by satellite communication. ICAO provides specified group of frequencies between fixed stations of the HF network.

Due to its wider coverage area, as we know, there are three types of Controls in aviation that uses VHF. Beyond the Area Control the use of VHF is not possible. Hence for coverage of area greater than 250NM from the ATC, HF communication is used. This is more prevalent in place where the aircraft is passing over sea area and communication between ATC and aircraft has to be established.

Tower Control(25NM)

Approach control(50NM)

Area Control(250NM)

In HFRT communication, HF controller controls the aircraft as well as communicates with the Area/Flight Information Centre, to provide aircraft position and flight levels.

Also, HFRT is used for control of VVIP flights from departure airport to destination airport.

In flight control each significant position is given a five alphabet name. Example- MABUL, RINDA, VATLA.

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Area Control

Approach Control

Tower Control

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This stands for Major World Air Route Area. It is exclusively used for providing International flights to provide information such as position reports, met reports, flight level clearance, etc. The available frequencies for MAWARA at Netaji Subhash Chandra Bose International Airport at Kolkata are:-

a. 10066KHz

b. 6556KHz

c. 3491 KHz

d. 2947KHz

Among these, the 1st two are used during the day (1 is main, 1 is standby), and the other two at night.

RDARA-

This stands for Regional Domestic Air Route Area. These are a set of designated frequencies for HF communication that are used to communicate with aircrafts to inform them about position, weather conditions etc. The frequencies for RDARA at AAI Kolkata Airport are:-

a. 8869KHz

b. 6583KHz

c. 8948KHz

HF TRANSMITTERIs an electronic device which, with the aid of an antenna, produces radio waves? The transmitter itself generates a radio frequency alternating current, which is applied to the antenna. When excited by this alternating current, the antenna radiates radio waves. In addition to their use in broadcasting, transmitters are necessary component parts of many electronic devices that communicate by radio, such as cell phones,

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Wireless computer networks, two way radios in Aircraft, ship, spacecrafts, radar sets, navigational beacons etc.

In AAI Kolkata:-Zenitel hf transmitters Model No.CST2002A having power output of 2.5KW are used for HFRT operations.

The said Transmitters are highly modular & used in fully remote controlled. The equipment covers a frequency range of 1.6MHz to 30MHz and offers simples, duplex and semi duplex radio operation.All the transmitters are used as individual Server. From Radio operating position, remotely any one transmitter can be selected for operation through UHF Link.

The transmitter contain four main blocks:-i) The transmitter Control System (TCS )ii) The digital frequency synthesizer (DFS )iii) The high power Amplifier ( HPA )iv) The power supplies

TCS

The TCS is based around two microcontroller modules i.e. the WEBLINK and the ADAM-5511. The ADAM 5511 controls the harmonic filter and the antenna matching unit and monitors the reflectometer outputs, enables the HF power output.

The WEBLINK controls power on/off, of Fans, the DFS and the HPA parts, control and monitors the ADAM-5511, the state of all HPA parts, DFS. It offers the human Machine Interface (HMI) to both the Local user (via local monitor and keyboard) and the Remote User(s) via an Ethernet connection.

DFS

Generates a modulated low power hf signal according to the selection of the user (carrier frequency), LF audio input, class of operation, power output level. The HF signal generation is fully digitized by the use of DDS (Direct Digital Synthesis) technique.

HPA

a) Driver 1:- Supply voltage 24Vdc, Gain ±26db, Class A amplifier.b) Driver 2:- Supply voltage 48Vdc, Gain ±17db, Class A amplifier.c) Power amplifier: - Supply voltage 48Vdc, Gain ±13.5db, Class AB amplifier.d) Reflectometers: - Measures both Forward and Reflected power used for antenna matching unit

and VSWR protection.e) Filters: - To eliminate the

harmonics in the power output.

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f) Matching unit: - Impedance matching for maximum RF power transfer and reduces the transmitter load to a VSWR of maximum 1.5.

Fig: PA Unit

BALUN

Conversion from balanced to unbalanced line, used before antenna.

ANTENNA

Open ended broadband dipoles are used.

Fig: Block Diagram of HF TransmitterHere, the transmitter uses a Digital Frequency Synthesizer (DFS) to generate the carrier frequency. 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.

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Fig: Direct Digital Synthesizer block diagramA 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.

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

Fig: Block Diagram of Ethernet Protocol Operation

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HF RECEIVERIntroduction :

HF stands for High Frequency. It operates on a range of 3 - 30 MHz HF operates at a range greater than 200NM. The wavelength of HF lies between a ranges of 100 - 10 meters.

HF Receiver:

Main parameters of any receiver:

Sensitivity :

It is the ability of any receiver to respond to a weak signal voltage and develop a standard output signal from that low voltage. Higher the sensitivity of the receiver, greater amount of weak signals will be picked up by the receiver.

Selectivity :

It is the ability of any receiver to select a particular frequency or a band of frequencies while rejecting the undesired ones. Selectivity increases with the no. of tuned circuits used.

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Here n indicates the no. of tuned circuits, the selectivity curve becomes narrower with increase in no. of tuned circuits.

The tuned circuits used consist of two elements: inductor and capacitor.

Fidelity :

It is a measure of the receiver's ability to reproduce the intelligence of a signal (it must reproduce as faithful as the signal that is received).

The receiver used for HF communication is AM super heterodyne 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: Super heterodyne system.

• Sensitivity: 2µV. This is the minimum voltage that can be detected by the receiver.

• Audio Output Impedance: 4 to 16 ohms.

Some frequencies of HF communication for Calcutta airport are 3491 KHz, 5471 KHz, 6556 KHz and 11125 KHz.

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VHF COMMUNICATIONVHF stands for Very High Frequency Communication. It is the most common means of airborne communication. VHF Communication System consists of VHF transmitter, receiver, Transceiver handset, control head, antenna and an interface to the aircraft audio system for access to the microphone or cockpit speaker.

Characteristics of VHF Communication:

VHF follows Line of Sight Communication or Point to Point Communication. Since the transmission is line of sight, the range depends on altitude of the aircraft and ground station.

VHF communication is used for short distance communication.

Frequency range of VHF Communication is in between 30 MHz and 300 MHz

VHF Communication is a Noise free communication.

As per ICAO, frequency range for AMS (Aeronautical Mobile Service) allotted 118 MHz to 136.975 MHz (for aviation purpose).

Range of VHF is 200 nautical miles.

In light aircraft, transceiver is mounted in the instrument panel and contains all the necessary controls and displays.

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In larger aircraft the control head which is used for selecting the receiver and transmitter frequencies is usually located in the centre console between the pilot and co-pilot, transceiver is remotely located in the radio rack.

VSWR (Voltage Standing Wave Ratio) for VHF is 1.05.

VHF TRANSMITTER PARK AIR T6T 50 WATT VHF (IP Base) Transmitter is intended for use in fixed ground environments

such as airports and en-route centres.

Transmitters are used for Voice Communication between Air traffic controller and pilot of aircraft and vice versa.

Power Output of VHF Transmitter: 50 Watt.

Modulation Technique used for VHF transmitter is AM (Amplitude Modulation).

Polarisation: Vertical Polarisation.

Propagation: Line of Sight

Type of antenna used : Folded Dipole

Cable used for connecting transmitter with antenna: Co- axial RF cable (impedance 50 ohm).

Power Supply: 230 volt AC or 24 volt DC normally

Transmitter can store frequency in its channel memory, Frequency accuracy better than 1PPM.

Environmental: Temperature range -20 degree to +55 degree.

Duty cycle 100% continuous operation.

Channel Spacing: 25 KHz/ 8.33 KHz.

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T6TACDC

Transmitting 500 VA 12 Amp

Ideal Mode 6 VA 1 Amp

Transmitter is tuned at the same time and at the same frequency as the receiver.

Offset Carrier System: It is a system which helps to connect the transmitter of another station when the signal strength is poor in the base station.

Accessories: VEP maintenance application and a VoIP configurator application is supplied. Connecting to Control equipment: 4 wire audio and PTT using analogue lines, E1 Link, Ethernet links.

In Airports Authority of India presently Kolkata Airport using IP based Voice Communication System and here IP based TX/Rx are used and it is the first time in India as well as in Asia.

Fig: Block Diagram of VHF Transmitter

A.A.I operates in 118MHz to 136.975MHz.It is a type of Line of Sight Communication.3 basic components required for VHF communication are transmitter, receiver and antenna.

VHF transmitter have two transmitters in a single equipment. One transmitter is on air while other is on Standby.

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VHF RECEIVERVHF receiver have two receivers in a single equipment. One receiver is on air while other is on Standby.

The antennas used for transmission are Directive antenna and Omni directional antenna.

VHF Receiver has the function of selecting the desired signal at VHF frequencies from all the other unwanted signal amplifying and demodulating it, and reproducing it in the actual shape or desired manner. It helps to receive the signals transmitted from another transmitter.

Fig: Block Diagram of VHF Transmitter

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AUTOMATIC MESSAGE SWITCHING SYSTEM (AMSS)

AMSS is a computer based system, centred 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

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 analysing, 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:

Line Switching

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Message Switching 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. In Electronics Corporation of India Limited (ECIL) AMSS, maximum features of automation like message switching, analysing, 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 User’s terminal

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

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.

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.

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AFTN (AERONAUTICAL FIXED TELECOMMUNICATION

NETWORK)The Aeronautical Fixed Telecommunication Network (AFTN) is a worldwide system of aeronautical fixed circuits provided, as part of the Aeronautical Fixed Service, for the exchange of various Aeronautical Messages and/or digital data between aeronautical fixed stations having the same or compatible communications characteristics which is necessary for ensuring safety of air navigation and the regularity of air traffic between aeronautical fixed stations of different states and between aeronautical stations.

Type of Messages.

DISTRESS MESSAGES ( priority indicator SS ).URGENCY MESSAGES ( priority indicator DD ).FLIGHT SAFETY MESSAGES: ( priority indicator FF ) [FPL-Flight Plan, DEP-Departure, ARR-Arrival. Etc].METEOROLOGICAL MESSAGES : ( priority indicator GG ) [1. Messages concerning forecast e.g. terminal aerodrome forecasts (TAFs), area and route forecasts. 2. Messages concerning Weather observations and reports of Aerodrome e.g. METAR, SPECI.]FLIGHT REGULARITY MESSAGES.AERONAUTICAL ADMINISTRATIVE MESSAGES.NOTAM MESSAGES (Priority indicator GG).

The message format of AFTN messages is defined in ICAO Annex 10 Aeronautical Telecommunications Volume II.

Example of AFTN message format ( FPL-Flight Plan) message:

ZCZC AEA0129 050358FF VECFZQZX VIDFZQZX VILKZTZX050356 VTBDZPZX(FPL-AIC67-IS-B744/H-SHIJDRYWZG/S-VTBD1900-N0514F320 L507 CEA R460 TEPAL R460 LLK R460W-VIDP 0330 VILK-EET/VYYF0025 VECF0122 VGFR0134 VECF0146 VIDF0130 REG/VTEFG SEL/DHGR DAT/SV RMK/TCAS EQUIPPED NAV/JRNAV DOF/160105)

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NNNN

EXPLANATIONS:

First Line represent the Heading of the message in which ZCZC is the Start-of-Message Signal, AEA0129 refers to the Transmission Identification and 050358 is an Additional Service Indication indicate Date and time of Transmission of the message.

Second Line represent Address consists of Two letter Priority Indicator (here it is FF), eight-letter group Addressee Indicators (here it is Delhi ATC, Lucknow ATC and Kolkata ATC). (Maximum 21 Addressee Indicators in 3 Address Line can be used for single message).

Third Line represent the Origin of the message consists of message Filing Time (six-digit date-time-group), the Originator Indicator (eight-letter group-Location Indicator & Unit, here it is Bangkok ATC ).

Next part (Here Fourth to Tenth Lines) represent the Message Text. Here it is a Text of FPL message. (When a text is exceeding 1800 characters, the message is divided into two or more parts).

Last Line/Last part is the Ending of the message is indicated by NNNN which is the End-of-Message Signal.

(Text of the Message will contain ZCZC or NNNN).

DECODE of above FPL message:

FPL- Message Type, AIC67-Aircarft Identification AIRINDIA67 , IS – Flight Rules(IFR) & Flight Type (Schedule).

B744/H-Aircraft Type (Boeing 744), H- Wake Turbulence(Heavy), SHIJDRYWZG/S-Equipment COM/NAV.

VTBD1900-Departure Aerodrome Location Indicator (Bangkok) & Time (EOBT-Estimated Off Block Time). N0514- Cruising Speed, F320-Flight level , L507 CEA R460 TEPAL R460 LLK R460W-ATS Route.

VIDP0330- Destination Aerodrome(Delhi) & EET(Total Estimate Elapsed Time), VILK- Alternate Aerodrome (Lucknow).

EET/VYYF0025 VECF0122 VGFR0134 VECF0146 VIDF0130 REG/VTEFG SEL/DHGR DAT/SV RMK/TCAS EQUIPPED NAV/JRNAV DOF/160105-Other Information consist of EET of each FIRs, Aircraft Registration(VTEFG),SELCAL CODE(DHGR), DOF(Date of Flight) etc.

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VOLMETVOLMET (French origin VOL (flight) and METEO (weather)), 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 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 half an hour.

The ranges used are:-

6676 KHz 11387 KHz 2965 KHz

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AUTOMATIC DEPENDENT SURVEILLANCE (ADS)

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: Demand report Event report Periodic report 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 ASDEIt has the potential to complement SSR.

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Position Reports Position Reports

ADS B Ground Station

CONTROLLER PILOT DATA LINK COMMUNICATION (CPDLC)

A means of digital communication between controller and pilot, using data link instead of voice.

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• 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

HFRT(HIGH FREQUENCY RADIO TELEPHONY)

High Frequency  Radio Telephony ( voice communication) is a part of Aeronautical Mobile Service reserved for air-ground communications between Pilots and Ground Controllers, related with the safety and regularity of flights, flying primarily along national or international civil air routes. As VHF

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coverage is insufficient due to range limitation to cover all portions of the routes flown, the use of HF frequencies are necessary because they provide long range communications coverage over Thousand miles.

In HFRT Network there are number of Aeronautical Stations to assist each other in order to provide the air-ground communication service required of the network by aircraft flying on the air routes for which the network is responsible.

In HFRT communication 2 frequencies are assigned to Aircrafts , one Higher frequency as Primary and one Lower frequency as Secondary.

HFRT communication reception affected by Atmospheric noise because Transmission is through sky wave propagation.

On HFRT following categories of Aeronautical Messages are handled:Distress, Urgency, Flight safety, Meteorological, Flight regularity. Example of Aircraft Position Report Message: AIC175 VABB-VECC POSITION NIPAD1105 FL350 EST KINKI1135 JJS NEXT SELCAL CODE FGDL

ATS Routes having number of reporting points which are many VOR codes like NNP. JJS etc and number imaginary 5 letter name like NIPAD,KINKI, MABUR,URKOK etc (which are having fixed coordinates).

HFRT STATION at NSCBI AIRPORT KOLKATA

Equipment: HF Transmitter ( ZENETAL) with SELCAL Facility & Remote Radio Receiver (ICOM) & ECIL AMSS workstation with ATC.

Language used: English

Hours of Operation: H24

Timings: In UTC

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HFRT NETWORK at Kolkata: 1. RDARA (Regional Domestic Air Route Area) for communication by Domestic Flights. Ground stations are Kolkata, Chennai, Portblair, Delhi & Mumbai. Frequencies used are 8861,8948,6583,5580,2872 KHz.

2. MWARA (Major World Air Route Area) for communication by International Flights. Ground stations are Kolkata, Dacca & Yangoon. Frequencies used are 10066,10051,6556,3491,2947KHz

In each Network one Frequency is maintained as Primary frequency and another frequency as Secondary frequency.

Higher frequencies are used during Day time and Lower frequencies are used during Night time.

VOLMET: ( Meteorological information for aircraft in flight ). Kolkata Radio broadcast VOLMET on HF.

Frequencies are 2965,6676,11387KHz. Broadcast time 5 minutes twice in every hour at interval of 30 minutes.(HR+05 to HR+10 , HR+35 to HR+40). Latest  MET REPORT of  KOLKATA, DACCA, KATMANDU & YANGON are broadcasted.

VOLMET Stations in India are at MUMBAI(VABB) & KOLKATA(VECC)

Communication Procedure: As per ICAO ANNEX10 VOL II & other various Documents.

SELCAL International aviation, SELCAL is a selective-calling radio system that can alert an aircraft's

crew that a ground radio station wishes to communicate with the aircraft. SELCAL uses a ground-based encoder and radio transmitter to broadcast an audio signal that

is picked up by a decoder and radio receiver on an aircraft. The use of SELCAL allows an aircraft crew to be notified of incoming communications even

when the aircraft's radio has been muted. Thus, crewmembers need not devote their attention to continuous radio listening.

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When a SELCAL decoder on an aircraft receives a signal containing its own assigned SELCAL code, it alerts the aircraft's crew by sounding a chime, activating a light, or both.

This uses DSB modulation technique.

ADVANCED SURFACE MOVEMENT GUIDANCE AND CONTROL SYSTEM

(ASMGCS)A-SMGCS (Advanced Surface Movement Guidance & Control System) is a system providing routing, guidance and surveillance for the control of aircraft and vehicles in the runway or ground in order to maintain the declared surface movement rate under all weather conditions within the aerodrome visibility operational level while maintaining the required level of safety.

A-SMGCS is a modular system consisting of different functionalities to support the safe, orderly and expeditious movement of aircraft and vehicles on aerodromes under all circumstances with respect to traffic density and complexity of aerodrome layout, taking into account the demanded capacity under various visibility conditions.

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Basic Functions:

A-SMGCS consists of four basic functions:

Surveillance Control Planning/Routing Guidance

A-SMGCS Levels

Implementation of A-SMGCS defines 4 levels:

A-SMGCS Level 1

Improved Surveillance makes use of improved surveillance and procedures, covering the manoeuvring area for ground vehicles and the movement area for aircraft. The procedures concern identification and the issuance of ATC instructions and clearances. The controllers are given traffic position and identity information which is an important step forward from the traditional Surface Movement Radar (SMR) image.

A-SMGCS Level 2

Surveillance + Safety Nets adds safety nets which protect runways and designated areas and the associated procedures. Appropriate alerts are generated for the controllers in case of conflicts between all vehicles on runways and the incursionofaircraft onto designated restricted areas.

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A-SMGCS Level 3

Conflict Detection involves the detection of all conflicts on the movement area as well as improved guidance and planning for use by controllers.

A-SMGCS Level 4

Conflict Resolution, Automatic Planning & Guidance provides resolutions for all conflicts and automatic planning and automatic guidance for the pilots as well as the controllers.

Fig: ASMGCS Layout of Runway

RADARRADAR 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”.

Types of Radar:-

Primary Radar-Here the active cooperation of the target is required.

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Secondary Radar-Here active cooperation of the target is not required. The transponder plays an important role here.

Applications of radar:-

It can be used for air traffic control, aircraft navigation, maritime navigation, meteorological applications, space applications, military applications and law enforcement purposes.

Radars used in CNS:-

Airport Surveillance Radar(ASR) Monopulse Secondary Surveillance Radar(MSSR) Secondary Surveillance Radar(SSR)

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Range of radar depends on:-Antenna gain, peak transmission power, atmospheric attenuation etc.

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

MSSRMonopulse Secondary Surveillance Radar (MSSR) is a radar system that can detect and measure the position of aircraft i.e. distance and angle and requests for additional information from the aircraft itself such as its identity and altitude.

MSSR technology is dependent upon the transponder. The radar sends an interrogating pulse and the aircraft replies to each query by transmitting a response containing encoded data bits. Since the aircraft sends a singlereplypulse, the technique is termed as Monopulse SSR technique. The Monopulse technique makes the

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communication process easier as it increases the azimuth accuracy. It helps in calculating the azimuth angle of the target w.r.t magnetic north.

The diagram shows a conventional main or "sum" beam of an MSSR antenna to which a "difference" beam has been added. The feed system is divided into two equal halves, the signal is distributed horizontally across the antenna aperture and the two parts are summed again to produce the original sum beam. However the two halves are also subtracted to produce a difference output. A signal arriving exactly normal, or at boresight, to the antenna will produce a maximum output in the sum beam but a zero signal in the difference beam. Away from boresight the signal in the sum beam will be less but there will be a non-zero signal in the difference beam.

The angle of arrival of the signal can be determined by measuring the ratio of the signals between the sum and difference beams.

There is one ENCODER present in the radar equipment box. It generates 16384 pulses in a 360ᴼ termed as Azimuth Count Pulse (ACP). By counting the no. of pulses we can calculate the value of azimuthal angle that the aircraft subtends with the magnetic North.

The formula can be given by Azimuthal Angle

¿ 360ᴼ16384

x (no .of ACPs at that point of time )

MSSR INTERROGATION

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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

SURFACE MOVEMENT RADAR (SMR)

Used to detect aircraft and vehicles on the surface of an airport.

Used by A Controllers to supplement visual observations.

Also used at night time and during low visibility to monitor the movement of aircraft and vehicles

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The Role of SMR

In the permanent absence of visual observation of all or part of the manoeuvring area or to supplement (or in poor visibility, replace) visual observation, SMR may be utilised to:

Monitor the movement of aircraft and vehicles on the manoeuvring area;

Provide routing information to pilots and vehicle drivers as necessary;

Provide advice and assistance for the safe and efficient movement of aircraft and vehicles on the manoeuvring area.

AIR TRAFFIC SERVICE (ATS) AUTOMATION SYSTEM

AUTOMATION SYSTEM – MISSION

To enhance the safety of the flights by providing the controllers with the information of air movements from

– Surveillance Sensors such as Radars, ADS-B, Multilateration Systems and weather data – Information such as Flight Plans, Route availability and Flow Management and communicate

control via Voice and Data Link.

The Kolkata ATM System is one of the most advanced safe and reliable ATM Data Processing and Display systems available today. It boosts safety measures and efficiently manages the future air traffic and reinforce Kolkata as an ATM reference for the whole Region.

MAIN CHARACTERISTICS OF AIRCON 2100

Open Architecture conforming to ISO/OSI. Commercial Intel processors from HP for Servers and Workstations.

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LINUX Red-Hat operating system. High Resolution Displays:

• 2048x2048: SDD screen for Radar Controllers

• 1600x1280: FDD screen

• 1600x1280: SDD screens for Tower

Data Base for DBM: PostgreSQL Use of high-level languages: ADA and C. Use of standard graphics: X-Windows and Motif The AirCon 2100 network is based in the Ethernet standards. All servers and workstations have connection to the double Operational LAN

AIRCON ADVANCED FUNCTIONS

Multi-Sensor Surveillance Data Tracking and Fusion Safety Nets (STCA, APW, MSAW) 4-D Trajectory Prediction Medium Term Conflict Detection (MTCD) RVSM Operation AIDC/ICAO Coordination System Availability & Recovery Surveillance Bypass Facility

State-of-the-art ATM features incorporated in the system, those have already been implemented and are in operational use, include but are not limited to:

– Advanced, user-friendly HMI specifically tailored for use by ACC/OCC, APP and TWR controllers, and by Flight Data operators.

– Enhanced multi-sensor surveillance tracking, including down-linked aircraft data, using Mode S radars, ADS-B and Multilateration (MLAT/WAM) data, as well as primary and secondary radar information.

– Air-Ground Data Link applications (ADS-C, CPDLC, DCL) and services for aircraft-controller interoperability.

– Advanced Flight Plan Processing and accurate 4-Dimensional Trajectory Calculation.

– Enhanced Safety Nets (STCA, MSAW, APW, APM, NTZ and others) and ATC Tools (Conformance Monitoring and MTCD), including conflict prediction/detection alerts and warnings.

– Integrated Air Traffic Flow Control and Management (Flow prediction and Arrival Manager (AMAN)).

Main Components

Radar Data Compressor Unit – RDCU Surveillance Data Processor – SDP Flight Data Processor – FDP

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Flight Data System – FDS Data Link Server – DLS Safety Nets (SFN)

Control Positions:

Situation Data Display – SDD Flight Data Display – FDD System Monitoring and Control - SMC Control and Monitoring Display – CMD Data Analysis Tool – DAT Arrival Manager – AMAN

Auxiliary Equipment:

Common Timing Facility – CTF Data Recording Facilities – DRF Data Base Manager – DBM Graphic Tool Interface – GTI

Simulation Environment:

Simulator System – SIM Pilot Instructor Position – PILOT TSS

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Data Analysis ToolsAdaptation data

DBM FDSDRF

Tracker &Safety nets

RADAR Messages Processing

RADAR Information

ADS/ CPDLC, DCL

DLS

RDCUSDP +SNET CWP

FDP

STATISTICSAFTN

COORDINATION

Aeronautical and flight information Processing

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Main System Components – Data Flow

Radar Data Compressor Unit

This processor centralizes the radar data reception from the radar. It can work in Main mode or in Alternate mode (By-Pass) if other one fails. This component is designed in redundant configuration in radar line reception, so as to easy to change the operative or reserve line manually or automatically.

Surveillance Data Processor -SDP

This component is in charge of handling of the primary, secondary and meteorological radar data provided by the radars connected to the system. It processes the information and sends it to the SDDs (Situation Data Displays) in order to show it on the controller screens. The SDP performs the following tasks

1. Flight Plans and received radar information correlation.2. Flight Plan Tracking3. Flight Handover Management4. Safety Alerts:

Minimum separation between aircrafts (Short Term Conflict Alert) Minimum Safe Altitude warning. Restricted Area warning Clear Level Adherence Monitoring, Route Adherence Monitoring. Heading Alert Distress Alert

5. ADS Tracking (if ADS is available)

Kolkata ATM System Context

Flight Data Processor (FDP)

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This component is in charge of Flights Plans management, generated or produced by external and internal sources. The FDP performs the following tasks:

Repetitive Flight Plans (RPL) management. Flight information inputs validation and check. Coordination between adjacent control centres (AFTN, OLDI, and AIDC if applicable)

management. Reception and validation of the AFTN communications Flight progression calculations. Medium Term Conflict Detection (MTCD). Flight plan information management and distribution. Strip printing (if it is applicable for the system). Restricted Areas Management.

Flight Data Service (FDS)

This function stores, collects and sends system real time data to external system (e.g. ASMGCS and other ATC centres) and historic data to be used by internal data analysis tools (e.g. traffic statistics, data test and verifying, events and log) and external tools (e.g. billing Airport FIDS).

Data Link Server (DLS)

The Air-Ground Data Link Processing (AGDLP) will be in charge of data link applications (ADS-C, CPDLC, DCL) between aircraft and controllers and ensures the data communications with the air-ground networks (ACARS) supplied by the service providers (e.g. SITA, ARINC).

The AGDLP is consists of following functions:

o ATS Facilities Notification Manager: It allows addressing capability for data link applications between aircraft and ground. The AFN application provides the capability to establish a logon between ATS ground and aircraft systems and peer ATS ground systems. The status of aircraft logged/de-logged is conveniently displayed to the controller.

o Automatic Dependent Surveillance – Contracts (ADS-C) Manager: It allows obtain positional and other information from suitably equipped aircraft in a timely manner in accordance with the established contracts between the Controller and the aircraft. The ADS-C Manager is responsible to initiate, maintain, by events and cancel simultaneous contracts of type periodic, on demand, by events or emergency. The periodical position report is used by the surveillance data processing for the aircraft tracking in non-radar coverage areas.

o Controller Pilot Data Link Communication (CPDLC) Manager: It allows exchange data messages between Controller and pilot. The CPDLC application provides the capability to established, manage and terminate dialogues initiated by the pilot or by the Controller.

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o Departure Clearance (DCL) Manager: It provides automated assistance for requesting and delivering departure clearances through the data messages exchange between tower personnel and pilot.

Safety Nets (SFN) Safety nets alerts provided for:

o Short Term Conflict Alert (STCA) – detection and prediction of hazardous situations between pair of tracks.

o Minimum Safe Altitude Warning – detection of track infringing, or predicted to infringe, terrain or the minimum safe altitude above terrain defined for MSAW areas. It also detects track predicted to deviate below the safe approach or departure path of defined aerodromes.

o Area Proximity Warning (APW) – detection of infringing tracks, or predicted to penetrate restricted, prohibited or danger areas.

o Approaching Path Monitoring (APM) and Warning – monitoring and detection of track deviating from the glide path and localizer at final approach.

o Distress, SPI and duplicated SSR Code Warning.o RVSM alert.o Specific ADS-C Alerts (RIE, NIC, ADS-C Emergency, FOM change).o Mode-S alert.

Control Positions:

Situation Data Display (SDD)

It is based on powerful workstations where the data, radar data, and flight plans presentations are carried out. These data are shown on the controller screens and it can show more information like geographical maps, airways, meteorological data etc.

Flight Data Display (FDD)

This component present information about flight plans but it does not present any data about air situations. It also allows the operators to manage the flight plans and other meaningful data like activation of restricted areas, manage repetitive flight plans, AFTN correction messages, flow control, Paged Information Pagination visualization, etc.

System, Monitoring and Control (SMC) / Control Monitoring Display (CMD)

It works as a component that supervises the whole system continuously and on real time. It also allows the management of the components that fails or the ones that are not working correctly.

Data Analysis Tool (DAT)

This function encloses a set of functions for the analysis and study of the system data (e.g. traffic statistics, data test and verifying, events and log) based on historic data provided by the Flight Data Service (FDS) function.

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Arrival Manager

It sequences the arrival flights for internal aerodromes, minimizing their arrival waiting times.

Auxiliary Equipment

Common Timing Facility (CTF)

It manages the reception of the GPS time and delivers it via LAN to all the components and all the clocks with NTP protocols.

Data Recording Facilities (DRF)

This component is based in the using of redundant RISC computers and records continuously all the data related to the tracks data, flight plans data, and the controller actions to allow a playback reproduction and analysis.

Data Base Manager (DBM)It provides the system with the necessary data for the creation and modification of the database adaptation data situating the system in its geographical environment and upgrading the efficiency of the system.

MULTILATERATION SYSTEM (MLAT)It is a navigation technique based on the measurement of the difference in distance to two stations at known locations that broadcast signals at known times.

Unlike measurements of absolute distance or angle, measuring the difference in distance between two stations 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, multilateration relies on multiple measurements: a second measurement taken to a different pair of stations will produce a second curve, which intersects with the first. When the two curves are compared, a small number of possible locations are revealed, producing a "fix".

Multilateration is a common technique in radio navigation systems, where it is known as hyperbolic navigation. These systems are relatively easy to construct as there is no need for a common clock, and the difference in the signal timing can be measured visibly using an oscilloscope.

Multilateration should not be confused with trilateration, which uses distances or absolute measurements of time-of-flight from three or more sites, or with triangulation, which uses the measurement of absolute angles. Both of these systems are also commonly used with radio navigation systems; trilateration is the basis of GPS.

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CENTRALISED MAINTENANCE UNIT (CMU)

CMU is a computer based system that is meant for communication (ground to ground & ground to aircraft), broadcasting meteorological reports and checking the flight-plan or route of the aircraft in the sky.

CMU means Centralised Maintenance Unit. It consists of the following parts:

VHF Receiver and Transmitter VCS Equipments HFRT Unit Equipment Room

VHF RECEIVER TRANSMITTER SECTION:

VHF stands for Very High Frequency radio range. It is used for ground to aircraft communication.

For communication purpose the frequency range used is 118 - 136.975 MHz The channel separation used is 25/ 8.33 KHz. Lesser the channel separation; lesser will be the

interference. The channel separation thus enhances the performance. The VHF output is maximum 50 Watts. In Kolkata, there are 22 frequencies in the given range; out of which 12 are used. The emergency frequency all over the world is provided as 121.5 MHz VHF can cover a range of 200 NM only due to earth curvature. It is used for LOS.

In the CMU section there is provision for using 24 transmitters and 48 receivers. The transmitters and receivers used are all IP based. Control personnel having the IP address can control the aircraft from anywhere of the world. The receivers and transmitters are connected to a 24 port Ethernet switch.

How the range of 200NM in VHF communication can be increased ?

200 NM

200 NM

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VECCVEGYVERPVEPT

VIBN

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In the earlier system; suppose for a flight from Kolkata to Varanasi; flight-plan; and all necessary information was passed in the following manner: VECC - VEGY; VEGY- VERP; VERP - VEPT; VEPT- VIBN. But nowadays with the help of MPLS (Multi-Protocol Label Switching) [provided by BSNL in Kolkata] which operates on TCPIP protocol the flight-plan can be viewed from anywhere. Thus the disadvantage of VHF was removed. Also by using RCAG (Remote Control Air to Ground) we can achieve the desired range.

The MPLS line has a B.W of 6 MBPS and the E1 lines (there are 3 lines) have B.W of 2 MBPS. The VHF transmitter receiver system operates on dual LAN system. There is one main system and there is one standby system for back up in emergency situations. The transmitters are marked as T6T and receivers are marked as T6R. The 22 frequencies are distributed among different sections e.g. 118.475 MHz is given to TWR2; 119.3 MHz is given to App FNL. Green symbol indicates a secured connection; while red indicates that the device has not been installed. The emergency frequency is given to TX’s (Transmitter Standby). The E1 lines are used to connect the following airports with Kolkata airport - VOVZ (Vizag), VEBS (Bhubaneswar), VARP (Raipur), VEJS (Jharsuguda), VEPT (Patna), VEBD (Bagdogra) and VEGT (Guwahati).

DUAL LAN NETWORK

VCS WORKSTATIONS (TOUCH PANEL)

There is an analog and a digital recorder to record all the voice communications taken place. The analog tape recorder consists of 128 channels with one main and a standby unit. The digital recorder consists of 750 channels divided amongst 3 sets. The digital recorder is IP based and is connected via RJ45 connector.

Recorded contents of analog recorder:

Frequencies Telephones Hotlines Status of the siren (checked at 8:30 AM)

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S4 CONTROLLER (isolated system for backup)

A

VCS

B

VCS

OLD REMOTE STANDBY TRANSMITTER

Main Main

Standby Standby

Receiver Transmitter

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S4 controller recording

Recorded contents of digital recorder: Frequencies Telephones Hotlines Status of the siren (checked at 8:30 AM) S4 controller recording Workstation records connected via MPLS line

To keep weather reports; there is one Digital Airport Terminal Information System (DATIS). It operates on 126.4 MHz and usually gives the meteorological reports at an interval of 30 minutes.

WEB-BASED CONTROL

INTRODUCTION

Zenitel Transmitter employs web based control for operation. This handout is an introduction to web based control.

In recent years, the Internet has proved a powerful tool for distributed collaborative work. The emerging Internet technologies have the potential to apply the advantages of this way of working to the high-level control of equipments. The advantages include:

Allowing remote monitoring and adjustment of equipments, Allowing collaboration between skilled managers situated in geographically diverse locations Allowing the business to relocate the physical location of equipment management staff easily in

response to business needs.

The design methodologies for the local computer-based control system are not appropriate for Internet-based control system, as they do not consider the Internet environment issues such as Web-based delay, Web-based safety, Web-based interface, and uncertain users.

NETWORKSA network is a system of hardware, software and transmission components that collectively allow two application programs on two different stations connected to the network to communicate well. Figure 1 shows a typical Network

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Fig: Typical Network

Networks are classified into several categories based on the application. Two important types of networks are:

Local Area Network Wide Area Network

Local Area Networks (LAN)

LANs are limited to short geographical distances in the case of home, office, building, campus, industrial park. Figure 2 shows a typical LAN

Fig: Typical Local Area Network

Some features of LAN are:

Customer premises operation: User firm chooses technology, User firm needs to manage on ongoing basis

Low cost per bit transmitted: Companies can afford high speed, 100 Mbps to the desktop is typical.

Wide Area Networks (WAN)

WANs are used to link sites at long distances. WAN requires the use of carriers to provide service. Figure 3 shows a typical WAN.

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Fig: Typical Wide Area Network

WANs are normally interconnect several LANs. Some main features of WAN are:

Limited and complex choices. High cost per bit transmitted. Companies cannot afford high speeds. Usually low speed (56 kbps to a few megabits per

second).

Network Topology

Network topology refers to the physical layout of the network. It refers to the physical location of the computers and how the cables run between them. The four commonly used topologies are the Bus, the Star, the Ring and the Mesh.

Transmission Media

Network transmission media is the medium over which the information is exchanged between the computers. Different mediums are used for this purpose namely Copper, Glass, Air, Radio etc. Each media has certain characteristic features that make it suitable for particular networks. In Zenitel network, Copper media in the form of Unshielded Twisted pair (UTP) cable is used for the LAN and Radio in the form of UHF Link is used for the WAN.

Interconnecting Devices

Various special devices are used to interconnect components of a network. These devices are the Hub (also called the Switch), the Router, the Bridge etc.

The Switches allow simultaneous communication between two or more nodes, at a time. Switches are used in single networks like LANs.

Multiple Networks are connected by Routers. An example of a Wide Area Network; the Internet is a group of networks linked together with routers in a way that allows an application program on any station on any network in the internet to be able to communicate with an application program on another station on any other network.

Routers examine the network address field and determine the best route for a data packet. They have the great advantage in that they normally support several different types of network layer protocols.

Network Protocols

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A protocol is a set of rules and formats that govern the communication between communicating devices in a network. Protocols can be broadly divided into hardware and software categories.

Hardware Protocols

Hardware protocols define the way the hardware device has to operate and work together. For example 10baseT Ethernet protocol is a hardware protocol specifying exactly the way the devices in a 10baseT Ethernet network are physically connected, the voltage levels on the cables etc. There is no software program involved, all is done with the hardware.

Software Protocols

Programs in a network communicate with each other via software protocols. Network servers and clients both have protocol packages that must be loaded to allow them to talk to each other.

Open System Interconnection (OSI) Model

The International Standard Organization (ISO) developed the OSI reference model 1n 1977. Since then this has become the most widely accepted model for understanding network communication. The OSI model is simply a conceptual framework made for better understanding of the complex interaction that takes place among the various devices in the network. The OSI model consists of seven layers namely Physical, Data Link, Network, Transport, Session, Presentation and Application layers as shown in fig.

Fig.

Each layer of OSI model has different protocols associated with it. When more than one protocol is needed to complete a communication process, the protocols are grouped together in a stack. In fact TCP/IP is a protocol stack.

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The Physical layer is responsible for sending the bits from one machine to the other through the transmission medium. Hubs, Repeaters, multiplexers etc. are all belong to physical layer in a network.

The main task of Data Link layer is to take the raw data and transform it into an organized data stream that appears free of transmission errors to the network layer. In order to facilitate this the data link layer adds control information to the data being sent. It also regulates the data flow rate.

The network layer is concerned with controlling the operation of the subnet. The data from the sender may be required to travel through several links / subnets to reach the receiver. It is the task of the network layer to make routing decisions and forward data packets. The Router is the network device which operates in the network layer.

The basic function of the Transport layer is to accept data from session layer, split it up into smaller units if needed and pass these to the network layer, and ensure that these pieces all arrive correctly at the other end. The transport layer is a true end to end layer, from source to destination. In other words a process on the sending machine carries on a direct conversation with the destination machine, using the message headers and control information.

The Session layer allows applications on separate computers to share a connection called a Session. A session allows ordinary data transport, as does the transport layer, but also provides enhanced services useful in some applications. A session might be used to allow a user to log on to a remote timesharing system or to transfer a file between two machines. Hence, one of the services of the Session layer is to manage dialogue control

Presentation layer is concerned with the syntax and semantics of the information transmitted. This layer translates data between the formats the network requires and the format the computer accepts. The major functions of this layer are protocol conversion, compression and encryption and interpretation of graphic commands.

The Application layer is the topmost layer of the OSI model, and it provides services that directly support user applications, such as database access, e-mail and file transfers. It also allows applications to communicate with applications on other computers as though they were on the same computer.

The figure 5 explains communication process between two devices connected in an OSI model.

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Fig 5

TCP/IP PROTOCOLTCP is a connection-oriented protocol that provides a virtual circuit between user application on sending and receiving machines. TCP takes the data from the application layer protocols and breaks it into segments and then makes sure that they reassembled at the receiving end.

IP takes the data from the host-to-host layer and fragments the information into packets. It labels each packet of the sending device and the IP address of the receiving device. IP also reassembles packets on the receiving machine into segments for upper layer protocols. IP is a connectionless protocol that has no interest in the contents of the packets. It simply moves the packets to the destination.

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IP Addresses

The source and Destination machines in a TCP/IP environment are given a 32 bit address called the IP Address. It consists of four 8 bit octets (each Octet is one byte). The IP address consists of network identifier part and the host identifier. The address is coded to allow variable allocation of bits to specify network and host. A typical IP address would be 192.32.64.200 (dotted decimal format). IP addresses are hierarchical addresses in that they provide different levels of information. It can give the network that the node resides on, the subnet it belongs to and the actual node address. This type of addressing makes routing practical.

IP Classes

IP addresses have been broken down into three classes based on the size of network namely Class A, Class B and Class C. Class A is used for very large networks and supplies over 16 million node addresses for the network, Class B is used for networks containing a lot of nodes. Class C is used for small networks.

Fig 6

NOTAMNOTAM:  Notice to Airmen originated by International NOTAM Offices (NOF) of each FIR to alert aircraft pilots of potential hazards along a flight route or at a location that could affect the safety of the flight.

A NOTAM shall be originated and issued promptly whenever the information to be distributed is of a temporary nature and of short duration or when operationally significant permanent changes, or temporary changes of long duration are made at short notice, except for extensive text and/or graphics.

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NOTAMs are distributed by means of telecommunication (AFTN), that contain information concerning the establishment, conditions or change in any aeronautical facility, service, procedure or hazard, the timely knowledge of which is essential to personnel and systems concerned with flight operations.

The International NOTAM Office (NOF) Kolkata is responsible to process and originate NOTAMs of all Airports & Airspace under Kolkata & Guwahati FIR and distribute all other NOFs and Airports through AMSS/AFTN. Kolkata NOF also receives NOTAMs from other NOFs through AMSS/AFTN.

All these NOTAMs are stored in AMSS DATABASE Server for retrieval and generation of Preflight Information Bulletin of NOTAMs for specific Aerodrome, FIR, Route for Pilots through ASBS Terminals (Automatic Self Briefing System ) installed at Communication Briefing.

An example of NOTAM:

(A0046/16 NOTAMN Q) VECF/QCAAS/IV/NBO/AE/000/999/A) VECC B) 1601090905 C) 1601091500 ESTE) VHF 125.775MHZ VECC-VEBD SECTOR NOT AVBL)

Decoder of above NOTAM:

A0046/16 – Letter A indicate the Series, 0046/16 4-digit NOTAM number followed by a stroke and two digits to indicate the year. [In India Series A for both International & National distribution, Series C for National distribution and Series D for facilities of Defense Aerodrome with National distribution].

NOTAMN - Suffix N Indicates this is a new NOTAM. Other options are R for NOTAM replacing another or C for one cancelling another.

Q) VECF/QCAAS/IV/NBO/AE/000/999/

This is the "Q" or qualifier line, it always starts Q) and contains the following fields, each separated by a stroke.

FIR (here VECF , Kolkata FIR)

NOTAM Code, a 5 letter code starting with Q, defined in Annex 15. 2nd & 3rd letters CA  indicates Facility ,that it concerns about Air Ground facility. A full list of codes is included in ICAO document 8126 (Aeronautical Information Services Manual).

IV - Indicates that this is significant for IFR and VFR traffic

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NBO - indicates for immediate attention of aircraft operators, for inclusion in PIB's and Operationally significant for IFR flights

AE - Indicates scope, here A is Aerodrome, E is Enroute ( W for NAV warning)

000/999 - lower and upper limits expressed as a flight level. In this case it has been left as the default as it is not applicable.

A) VECC - ICAO Location indicator of the Aerodrome where the facility is.

B) 1601050905 – Year 2016, Month 01 (January), Date 05, Time (HR&MIN) group (0905UTC) when this NOTAM becomes effective.

C) 1601051500 EST - Date/time group (UTC) when the NOTAM ceases to be effective. Note "EST" means "estimated". All NOTAM with EST remain in force until cancelled or replaced.

D) Time Schedule ( In this type NOTAM it is not required and not used)

E) VHF 125.775MHZ VECC-VEBD SECTOR NOT AVBL) - text of the NOTAM using ICAO abbreviations.

NAV-AIDSNAV-AIDS: Stands for navigational aids. They are the tools which helps the aircraft in various navigational functions such as aircraft take-off, landing and also helps it to maintain a correct bearing on its route towards its destination.

NAV-AIDS are generally of four types:-

1) NDB (Non-directional beacon)

2) VOR (VHF Omni range)

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3) DME (Distance measuring equipment)

4) ILS (Instrument landing system)

*NON-DIRECTIONAL BEACON (NDB): It helps the aircraft to determine its own position with respect to the station/airport. It works on MF band. The range of frequencies allotted to it is 200 to 400 KHz. It helps in: 1) En-route aid2) Homing3) Position Fix

*VERY HIGH FREQUENCY OMNI RANGE (VOR): The main purpose of the VOR is to provide the navigational signals for an aircraft receiver which will allow the pilot to determine the bearing of the aircraft to a VOR facility. It also helps the aircraft in the scopes of the controller to be identified easily. The VOR generally uses a frequency range between 108 to 118 MHz

The VOR’s are generally of two types:-

1) Terminal VOR-Not so commonly used

2) En-route VOR –This is the more frequently used and the maximum attainable frequency present in this is 117.5 MHz

The models of VOR’s used in AAI are:-

1) Conventional VOR(CVOR)2) Doppler VOR(DVOR)

Conventional VOR include the LORENZ, WILCOX models.

Doppler VOR’s include the models such as AWA,GCEL, and THALES-432 etc.

Nowadays THALES-432 is the most commonly used VOR.

Generally it has been found that the DVOR have better precision rates and are less error prone than the CVOR’s. The DVOR uses the Doppler principle which states that an apparent frequency is generated when there is relative movement between then source and the receiver.

NON-DIRECTIONAL BEACONS(NDB)

(Frequency range 190-535 KHz)

A non-directional (radio) beacon (NDB) is a radio transmitter at a known location, used as an aviation or marine navigational 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

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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 call sign 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; coloured 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.

DVOR(Frequency range 112-118 MHz)

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

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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 fc±9960

The 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.

DME

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

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Purpose and use of ILS:

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The Instrument Landing System (ILS) provides a means for safe landing of aircraft at airports under conditions of low ceilings and limited visibility. The use of the system materially reduces interruptions of service at airports resulting from bad weather by allowing operations to continue at lower weather minimums. The ILS also increases the traffic handling capacity of the airport under all weather conditions.

The function of an ILS is to provide the PILOT or AUTOPILOT of a landing aircraft with the guidance to and along the surface of the runway. This guidance must be of very high integrity to ensure that each landing has a very high probability of success.

COMPONENTS OF ILS:

The basic philosophy of ILS is that ground installations, located in the vicinity of the runway, transmit coded signals in such a manner that pilot is given information indicating position of the aircraft with respect to correct approach path.

To provide correct approach path information to the pilot, three different signals are required to be transmitted. The first signal gives the information to the pilot indicating the aircraft's position relative to the center line of the runway. The second signal gives the information indicating the aircraft's position relative to the required angle of descent, whereas the third signal provides distance information from some specified point.

These three parameters which are essential for a safe landing are Azimuth Approach Guidance, Elevation Approach Guidance and Range from the touch down point. These are provided to the pilot by the three components of the ILS namely Localizer, Glide Path and Marker Beacons respectively. At some airports, the Marker Beacons are replaced by a Distance Measuring Equipment (DME).

This information is summarized in the following table.

ILS Parameter ILS Componenta. Azimuth Approach Guidance Provided by Localizerb. Elevation Approach Guidance Provided by Glide Pathc. Fixed Distances from Threshold Provided by Marker Beaconsd. Range from touch down point Provided by DME

Localizer unit: The localizer unit consists of an equipment building, the transmitter equipment, a platform, the antennas, and field detectors. The antennas will be located about 1,000 feet from the stop end of the runway and the building about 300 feet to the side. The detectors are mounted on posts a short distance from the antennas.

Glide Path Unit:

The Glide Path unit is made up of a building, the transmitter equipment, the radiating antennas and monitor antennas mounted on towers. The antennas and the building are located about 300 feet to one side of the runway center line at a distance of approximately 1,000 feet from the approach end of the runway.

Marker Units :

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Three Marker Units are provided. Each marker unit consists of a building, transmitter and directional antenna array. The system will be located near the runway centre line, extended. The transmitters are 75 MHz, low power units with keyed tone modulation. The units are controlled via lines from the tower

The outer marker will be located between 4 and 7 miles in front of the approach end of the runway, so the pattern crosses the glide angle at the intercept altitude. The modulation will be 400 Hz keyed at 2 dashes per second.

The middle marker will be located about 3500 feet from the approach end of the runway, so the pattern intersects the glide angle at 200 feet. The modulation will be a 1300 Hz tone keyed by continuous dot, dash pattern.

Some ILS runways have an inner marker located about 1.000 feet from the approach end of the runway, so the pattern intersects the glide angle at 100 feet. The transmitter is modulated by a tone of 3000 Hz keyed by continuous dots.

Distance Measuring Equipment (DME):Where the provision of Marker Beacons is impracticable, a DME can be installed co-located with the Glide Path facility.

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The above figure shows the typical locations of ILS components

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The ILS should be supplemented by sources of guidance information which will provide effective guidance to the desired course. Locator Beacons, which are essentially low power NDBs, installed at Outer Marker and Middle Marker locations will serve this purpose.

Aircraft ILS Component:

The Azimuth and Elevation guidance are provided by the Localizer and Glide Path respectively to the pilot continuously by an on-board meter called the Cross Deviation Indicator (CDI).Range information is provided continuously in the form of digital readout if DME is used with ILS. However range information is not presented continuously if Marker Beacons are used. In this condition aural and visual indications of specific distances when the aircraft is overhead the marker beacons are provided by means of audio coded signals and lighting of appropriate colored lamps in the cockpit.

FUNCTIONS OF ILS COMPONENTS:

A brief description of each of the ILS components is given in this section.

Function of Localizer unit :

The function of the Localizer unit is to provide, within its coverage limits, a vertical plane – o f c o u r s e a l i g n e d with the extended center-line of the runway for azimuth guidance to landing aircraft. In addition, it shall provide information to landing aircraft as to whether the aircraft is offset towards the left or right side of this plane so as to enable the pilot to align with the course.

Function of Glide Path unit:

The function of the Glide Path unit is to provide, within its coverage limits, an inclined plane aligned with the glide path of the runway for providing elevation guidance to landing aircraft. In addition, it shall provide information to landing aircraft as to whether the aircraft is offset above or below this plane so as to enable the pilot to align with the glide path.

Function of marker Beacon / DME:

The function of the marker beacons,/DME is to provide distance information from the touch down point to a landing aircraft.

The marker beacons, installed at fixed distances from the runway threshold, provide specific distance information whenever a landing aircraft is passing over any of these beacons so that the pilot can check his altitude and correct it if necessary.

The DME, installed co-located with the Glide Path unit, will provide a continuous distance information from the touch down point to landing aircraft.

Function of Locators:

The function of locators, installed co-located with the marker beacons, is to guide aircraft coming for landing to begin an ILS approach.

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CONTROL AND INDICATIONS IN AIRBORNE RECEIVER:

Block Diagram ILS Airborne Receiver

The salient features of the airborne display unit are as below:

a) There are two needles (vertical needle for localizer and the horizontal one for glide path).b) There are two lines, vertical and horizontal, crossing each other at the centre of the meter and graduated

by a series of dots. There are four dots above and four below the central dot on the vertical line. Similarly there are four dots left and four dots right of the central dot on the horizontal line.

c) The Localizer and Glide Path needles are driven by the DDM of respective radiation.

LOC GLIDE SLOPE INDICATOR AND RECEIVER

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CONCLUSION

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 importance of team spirit. The training included AMSS, VOLMET, ADS, CPDLC, HFRECEIVER, ASMGCS, SMR, RADAR, DME and ILS. We learned not only through theory classes but also through familiarisation of equipments.In my opinion, I have gained lot of knowledge and experience needed to be successful in Aviation communication engineering.

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BIBLIOGRAPHY

•Training material provided by the Airports Authority Of India

•http://en.wikipedia.org/wiki/Instrument_landing_system

• http://en.wikipedia.org/wiki/Radar

•http://en.wikipedia.org/wiki/Automatic_dependent_surveillance

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