G azərbaycan respublikasi təHSİl naziRLİYİ azərbaycan texniKİ universiteti M. M. QƏNDİLova e. Q. İsmayilova

JOKE, LAUGHS, SMILES
First student: “The dean says he is going to stop smoking in the college.”

Second student: “Wow! Next thing he’ll be asking us to stop it.”

UNIT X
Language is the dress of thought

Johnson Samuel
PRINCIPLES OF MODERN RADAR

A radar ( an abbreviation of : radio detection and ranging) is a composite radio-electronic apparatus to be used for detecting and locating objects and targets, such as aircraft, ships, buildings, mountains, and even people at various distances and with incredible accuracy, even when darkness, fog or clouds make targets invisible.

A radar consists of essentially of microwave transmitter, an antenna system, a microwave receiver, a timer or synchronizer and an indicator -all working with microsecond precision.

Radio energy is broadcast in any desired direction. In striking an object or target, a minute portion of the radio energy is reflected and returns to the radar within a few thousands of a second. Knowing the speed of radio energy ( 186.000 miles per second) and measuring time differences between the transmitted energy and any reflected echoes, it is possible to transmit these data electronically into direct distance or range – from radar to each object or target.

To determine the exact location of any target is made possible through accurate measurements of range, altitude, and azimuth, whether the target is in space, on the ground or on the sea. The data obtained ( directly or through electronic processing ) are displayed continuously on an indicator. This is usually a cathode-ray tube, the type of which is dependent on the kind of data to be displayed: range, altitude, azimuth, or other.

Modern radar has advanced far beyond the heavy equipment of short range and limited accuracy that appeared as one of the major technical achievements after World War II.

Through continuous improvement it has been possible to increase the range of modern radar to global and even outer-space distances. Accuracy having been infinitely improved through increased use of microwaves and the development of electron tubes capable of handling such wave lengths, the usefulness of radar has been considerably expanded.

Radar has many peaceful uses. To help navigation at sea small radars are installed on small commercial vessels, and larger setups are used on ocean-going liners and transports.

Aboard aircraft radar is used to make air navigation and flight safe, and to map areas over which the plane is flying. Ground-based radar is used to control flights of aircraft.

In detecting storms, radar can locate heavy clouds associated with various weather disturbances,

Whatever the application, the basic principles of all types of radar equipment are deeply rooted in radio and electronics.