The document provides an overview of radar technology, explaining its operation, key concepts, and performance factors such as signal-to-noise ratio and radar cross-section. It discusses how radar measures distance and direction to detect and locate various targets, including aircraft and ships, and outlines the components involved, such as antennas, transmitters, and duplexers. Additionally, it emphasizes radar's capability to function in challenging conditions where optical sensors may fail.

1. RADAR AND NAVIGATION

2. Module - I Introduction to Radar Radar –
concept - block diagram – operation –
frequency ranges – applications – range
equation derivation (no problems) - Radar
performance factors – minimum detectable
signal -receiver noise –Signal to Noise ratio -
Radar cross section of targets – transmitter
power – pulse repetition frequency –range
ambiguities

3. RADAR BASIC CONCEPTS
(Merill.l.Skolnik (1), Radiant (1.2))
• RADAR means Radio detection & ranging
• detection & location of aircraft, ships, spacecraft, vehicles
etc
• Distance is determined by measuring the time taken for
radar to travel to the target and back
• direction or angular position of target may be determined
from the direction of arrival using narrow antenna beams
• Rlative motion determined by shift in carrier frequency

4. FEATURES OF RADAR
I. • Operates by radiating energy into
space & detecting the echo signal
reflected from the target
II. • Extends human eyes capacity under
difficult conditions like darkness, heavy
rain, fog, snow etc
III. • Using radar it is possible to detect
location, distance, speed & direction of
target
IV. • Can work in conditions which are even
impervious to optical & infrared sensors

5. RADAR BLOCK DIAGRAM

6. Duplexer and Antenna
• Single antenna for both transmission & reception. Its
usually a gaseous device that produces a short circuit (arc
discharge) at the input to the receiver when the transmitter
is operating, so that high power flows to the antenna and not
to the receiver. On reception the duplexer directs the echo
signal to the receiver and not to the transmitter.
• Antennas can be mechanically steered parabolic reflector,
mechanically steered planar arrays, or electronically steered
phased arrays. A phased array is a collection of numerous
radiating elements whose signals combine in space to
produce a radiating plane wave.

7. Transmitter
Power Amplifier
• Modulator turns off /on transmitter
• Power amplifiers like klystron , travelling wave tube
, transistor amplifier or high power oscillators like
magnetron acts as transmitter.
• Output of transmitter is delivered to the antenna
by a waveguide or other forms of transmission line.

8. Waveform generator
• Generates radar signal at low power. This
signal acts as the input of power amplifier
Pulser Modulator
Transmitter is turned on/off by pulser with
the help of a periodic pulse