عنوان مقاله [English]
There have been many ways of collecting data from a long time ago. Astronomical observation of land surveying, hydrography, photogrammetry and remote sensing are the main methods of location-based collection of information. Radar remote sensing is an interesting and special issue that reveals different aspects of remote sensing. Radar sensors called active sensors can capture images in almost all conditions, and obstacles like rainfall, cloud and night can not cause them any trouble. The term radar, which is used today throughout the world, has become an international term like radio and television. In fact, radar invention has been taken from a very natural physical phenomenon called reflection. Radio and electromagnetic waves are also capable of reflection, and the radar is based on this simple property. The simplest radars were actually formed by a transmitter and a radio receiver. Radar is an electromagnetic system that is used to detect and determine the target’s position. With the help of the radar the inside parts of environments like darkness, rain, snow mist, dust, and … that are impenetrable to the eye become visible. However, the most important advantage of the radar is its ability to determine the distance from the target’s range. The application of radars is for ground, air, marine, spatial and meteorological targets. Fabricating a high-capacity system for tracing phenomena and creating high-quality images of them is the main goal of the construction of imaging radar. In this article, we have tried to introduce active sensors in general to emphasize on radar systems and the mechanism of their operation, and to introduce the features of these images and provide a ground for more applied research in the future.