How does GPR works?
GPR propagates electromagnetic waves into the earth by a moving antenna. These waves are reflected when they encounter any difference in dielectric constant and collected by the processor. As the antenna approaches the object, the reflection time becomes shorter and shorter. The reflection time is shortest when the object is directly below. There on, reflection time starts to increase when the antenna passes the object. If the scanning path is perpendicular with the target line, the image in the screen will appeared a perfect hyperbola in the case of round objects.
