Radar: Defence and Offence

Abstract

Although the principle of radar will be familiar to the general reader, it is worth summarising its advantages and limitations. Radar operates by projecting electromagnetic waves which reflect distant moving objects such as ships, aircraft or vehicles. The echo from these reflecting objects is measured by the time it takes to reach the observer who is watching for it. The immense advantage of radar is that it can ‘see’ through darkness, cloud or fog and targets cannot avoid detection by imposing radio silence. Accuracy in detection is improved by operating on shorter wavelengths. They may be used to scan an area to find an aircraft, the periscope of a submarine or a vehicle on the ground. Radar beams may be transmitted from static or mobile stations on the ground or from sets installed in ships or in aircraft. Radar can also provide a picture of a target area which is presented on a cathode ray tube or screen.