BHARAT ELECTRONICS LIMITED

SUMMER TRAINING PROJECT REPORT On

Study of departments and IFF RADAR system

About BEL – The Industry• BEL was established in 1954 as a Public Sector Enterprise under

the administrative control of Ministry of Defence as the fountain

head to manufacture and supply electronics components and

equipment.

• BEL was born to meet the growing needs of Indian Defence

services for Electronic systems.

•  Multi- product, Multi-unit ,Technology driven and one of

NAVARATANA titled PSU company.

• BEL has total 9 units distributed in various parts of country

• First and largest unit is at Bangalore (which is corporate office).

• Second largest unit is Ghaziabad unit

 

ROTATION PROGRAMMEUnder this ,the students are introduced to the company by putting them under a rotation program to various departments.

List of Departments I visited under rotational program include: 

• TEST EQUIPMENT & AUTOMATION

• QUALITY CONTROL (WORKS)

• MAGNETICS

• MICROWAVE LAB

• CS- ELECTRICAL

• WORKS ASSEMBLY-RADAR

1.TEST EQUIPMENT & AUTOMATION

• This department deals with test instruments at BEL. Examples : Oscilloscope (C.R.O) , Multimeter , Signal Analyzer, Logical Pulsar, Counters, Function Generator etc.

• Test equipment and automation laboratory deals with the equipments used for testing and calibration

Calibration is comparison of equipment under test with standard one.

• Test equipments are compared with the standard of National Physical Laboratory (NPL).

• BEL follows ISO( International standard Organization) standard

• The test equipment is calibrated either half yearly or yearly.

• After testing, different tags are labeled on the equipment according to the observations.

GREEN --- O.K, Perfect YELLOW --- Satisfactory but some trouble is present RED --- Cannot be used, should be disposed off. 

2.QUALITY CONTROL WORKS

• This department ensures the quality of product and inspects items manufactured in BEL.

• Mistakes in P.C.B.’s recognized as D & E mistakes Shop mistakes Inspection mistakes

• After a mistake is detected , following actions are taken- observation made Object code given. Division code given Change code prepared Recommendation action taken.

3. MAGNETICS• All types of transformers & coils used in various RADAR and

comm. Systems are manufactured .• 3 sections:  1.) PRODUCTION CONTROL :- Plan the production

2.) WORKS (PRODUCTION) :- Production of transformers/coils

3.) QUALITY CONTROL :- After manufacturing ,the item is offered to the inspection department to check the electrical parameters(DCR, No load current, full load current, dielectric strength, inductance , insulation resistance and mechanical dimension)• Various types of transformer being made are:

1.Open type transformer

2.Oil cooling types transformer

3.Moulding type transformer

4.PCB mounting type transformer

4.MICROWAVE LABORATORY• Very high frequency measurements take place in this

section• Testing of microwave components is done with the

help of various radio and communication devices• Different type of waveguides are tested in this

department like rectangular waveguides, circular waveguides

• Power measurements are done for microwave components because current and voltage are very high at such frequencies.

5.ELECTRICAL

• This department supplies power to all the production units & other parts of the factory

• 1 main station & 5 sub - stations at different locations in the company

• Power is received from the Uttar Pradesh Vidyut Board through 33 KV power line .

• At the main station, the power is stepped down to 11KV using 33/11KV step down transformer

• 5 sub-stations receive the power from main station at 11KV & stepped down to 433 V for the use of various machines in the factory.

• Transformers used at various sub stations are of rating 1600 KVA

6.WORKS ASSEMBLY

• Main function: to assemble various components, equipments and instruments in particular procedure

• Stepwise procedure followed by work assembly department is:

1. Preparation of part list to be assembled.

2. Preparation of general assembly.

3. Schematic diagram to depict all connect to be made and brief idea about all components.

4. Writing list of all components.

In work assembly , the procedure of things done include:• MATERIAL RECEIVE • PREPARATION• TINNING : resistors, capacitors and other components are tinned

with the help of tinned lead solution• MOUNTING : soldering of the components of P.C.B. plate• WAVE SOLDERING: This is done in a machine and solder sticks on

the entire path, which are tinned. Wave soldering machine consists of following parts:

o Conveyoro Fluxero Heatero Flux Cleaner• TOUCH UP : done at hand after finishing• INSPECTION • HEAT AGEING• LACQUERING

INTRODUCTION to RADAR and

IFF system

Basics of RADAR • RADAR stands for “RADIO DETECTION AND RANGING”

• Electromagnetic system for detection and location of objects such as aircraft, ships, spacecraft, people etc.

• Operates by radiating energy into space and detecting the echo signal reflected from an object or target.

• Can operate in darkness, fog, rain, snow.

• one major advantage : measure distance with high accuracy and in all weather.

Basic Block Diagram of RADAR

• Transmitter is capable of sending out a large UHF or microwave power through the antenna .

• A portion of transmitted energy is intercepted by the target and reradiated in many directions.

• The receiver receives, analyses, and displays the informtion in the reflected echoes picked up by the antenna.

• Information is processed to detect the presence of the target and determine its location..

The single antenna is used for transmitter and receiver with the help of a switch called duplexer. Duplexer switches the control between transmitter and reciever .

Fig. showing principle of RADAR operation : The transmitted pulse has already passed the target, which has reflected a portion of the radiated energy back toward the radar unit.

BASIC RADAR SYSTEM

TRANSMITTER- Sends large UHF or microwave power through the antenna.

RECEIVER- Receives, analyses the reflected echos picked up by the antenna.

DATA RECORDER- Records the coded information

PROCESSOR- Processes the information and displays it.

To calculate distance of target

D = v * t where D- distance/range of target in nautical miles [1 nautical mile=1852m] v- velocity of pulse t – time taken for the radar to travel signal to the target and back/ 2

To find target’s location in angle:From the direction the narrow beam width radar antenna points when the received echo is of max amplitude.If target is in motion, there is a shift in the frequency of the echo signal due to the Doppler Effect.

TYPES OF RADARBased on its function RADAR is classified as: 1. Primary radar. 2. Secondary radar.

A PRIMARY RADAR locates an object bytransmitting a signal and detecting the reflected echo.

A SECONDARY RADAR SYSTEM is similar in operation to primary radar except that the return signal is radiated from a transmitter on board the target rather than by reflection. In other words, secondary radar operates with a co-operative ACTIVE TARGET while the primary radar operates with a PASSIVE TARGET.

IFF

• Identification Of Friend or Foe (IFF)

• Radar Beacon System for air traffic control

• It is a secondary RADAR system

• Purpose : general identification of military

targets.

• The beacon system when used for the control of

civil air traffic is called as SECONDARY

SURVEILLANCE RADAR (SSR).

• Secondary radar system consists of an interrogator and a transponder.

• A ground based transmitter , the interrogator, broadcasts a radio signal to the air craft

• A transponder on the aircraft would receive and reply to this signal

• The interrogator transmitter operates in S Band at 1030 MHz and

the airborne transponder operates at 1090 MHz.• If the plane did not respond correctly, then the system determines the target as an Enemy aircraft .

ADVANTAGES OF SSR OVER PRIMARY RADAR: 

1. Reply pulses are stronger than the echo signals of primary

radar.

2. Separate transmitting and receiving frequencies eliminate

ground clutter and weather return problems.

3. Reply signal is independent of target cross section.

4. Interrogation and reply path coding provide discrete target

identification and altitude data.

IFF (MK-XI)

PURPOSE Identification Friend or Foe Mk-XI (IFF - Mk XI) Ground Equipment is used to interrogate and identify the ship/aircraft (target) fitted with compatible transponder.

IFF MK-XI has two parts as follows:1. IFF MK-X System2. Selective Address Interrogation (Mode `S') Feature

IFF MK-X system-operates on the principle of a Secondary Radar-Ship borne Interrogator sends out RF pulses, called mode pulses-Transponder receives pulses and sends out suitable replies

IFF INTEROGATION SIGNAL• A signal consisting of 3 pulses : P1, P2 and P3• P1 and P3 pulses are known as the INTERROGATE PULSES • Pulse P2 is known as the CONTROL PULSE• P1, P2 and P3 are of same width viz 0.8 microseconds each• P1 and P3 pulses occur at discrete pulse intervals • P1, P3 combination is known as MODE• Aircraft transponder on receipt of P1and P3 recognizes the

mode and responds with its suitable reply code

P1 P2 P3

Depends on working mode

0.8us

The mode is designated by the P1-P3 inter pulse interval.

IFF Mk-X Interrogator has four types of interrogation modes

Mode 1 and 2 are used for Military Interrogations. Mode 3/A is common to both Military and civil systems, and Mode C for eliciting the digitally encoded altitude from the airborne transponder

APPLICATIONS OF RADAR

Air traffic control

Ship safety

Space

Remote listening

Military

SOME RADARS MANUFACTURED by BEL at GHAZIABAD unit :

INDRA

REPORTER

CAR(ROHINI- REWHTi

FLYCATCHER

SRE

TCR (Akash)

THANK YOU