John Hutchison & Ronnie Milione

Introduction about Radar

The basic principle of operation of primary radar is very easy to understand, however, the theory can be quite complex. An understanding of the theory is essential to correctly specify and operate primary radar systems. Implementation and operation of primary radars systems involves a wide range of disciplines including building works, heavy mechanical and electrical engineering, high power microwave engineering and advanced high speed signal and data processing techniques. Some laws of nature have a greater importance here, though.

Radar measurement of range, or distance, is made possible because of the properties of radiated electromagnetic energy.

• This energy normally travels through space in a straight line, at a constant speed, and will vary only slightly because of atmospheric and weather conditions. (The effects atmosphere and weather have on this energy will be discussed later; however, for this discussion on determining range, these effects will be temporarily ignored.)
   
• Electromagnetic energy travels through air at approximately the speed of light,
  • 300,000 kilometers per second or
  • 186,000 statute miles per second or
  • 162,000 nautical miles per second.
  
   
• Reflection of electromagnetic waves
  The electromagnetic waves waves are reflected if they meet an electrically leading surface. If this reflected wave is registered again at the place of the origin, this is a proof of this that an obstacle is in the propagation direction.