A SHORT HISTORY OF RADAR

The principles of radar are not new; in fact, some early experiments were made back in the 1880s. In 1904 a German engineer had invented, as he explained, a "radio-echo collision prevention device". By 1922 the famed electronics engineer, Marconi, devised a principle for sending radio signals between ships which would be reflected back, to a receiver on the sending ship and thereby immediately reveal the presence and bearing of the other ship in fog or thick weather. This is the basic principle used in all radar.

Further improvements on this concept were developed, including the introduction of the "pulse" principles on which modern radar is based. During the period 1935 - 1940, successful pulse radar systems were produced independently and, nearly at the same time, in the United States, England, France and Germany.

Theapplication of radar inthe air traffic control system consists of two basic designs. The initial type of radar, called primary radar, began to be used in most parts of the world in the early 1950s. Another form of radar, secondary surveillance (SSR) is used for advanced air traffic control. When the word "radar" is used alone, it usually includes both primary and secondary radar.

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AIMS AND OBJECTIVES OF ICAO

Aims and objectives of ICAO are to develop the principles and techniques of international air navigation and to foster the planning and development of international air transport so as to:

ensure a safe and orderly flow of international civil aviation throughout the world;

encourage the arts of aircraft design and operation for peaceful purposes;

encourage the development of airways, airports, and navigation facilities for international civil aviation;

meet the needs of peoples of the world for safe, regular, efficient and economical air transport;

prevent economic waste caused by unreasonable competition;

ensure that the rights of Contracting States are fully respected and that every Contracting State has a fair opportunity to operate international airlines;

avoid discrimination between Contracting States;

promote safety of flight in international air navigation;

promote generally the development of all aspects of international civil aeronautics.

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NAVIGATIONAL AIDS

When flying, there are a number of aids available to pilots, though not all airports are equipped with them. A Visual Approach Slope Indicator (VASI) helps pilots fly a perfect approach for landing once they have found the airport. Some airports are equipped with a VHF omnidirectional range (VOR) to help pilots find the direction to the airport. VORs are often accompanied by a Distance Measuring Equipment (DME) to determine the distance to the VOR. VORs are also located off airports, where they serve to provide airways for aircraft to navigate upon. In poor weather, pilots will use an Instrument Landing System to find the runway and fly the correct approach, even if they cannot see the ground. The number of instrument approaches based on the use of the Global Positioning System (GPS) is rapidly increasing and may eventually be the primary means for instrument landings.

Larger airports sometimes offer Precision Approach Radar (PAR), but these systems are more common at military air bases than civilian airports. The aircraft's horizontal and vertical movement is tracked via radar, and the controller tells the pilot his position relative to the approach slope. Once the pilots can see the runway lights, they may continue with a visual landing.

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Date: 2015-12-11; view: 697