GPR devices must be moved across a surface since the objects are stationary.  Most GPRs have wheels and are pushed or pulled over the ground.  The main features are the transmitting antenna, the receiving antenna, and the display.  On some models there is only one antenna, which transmits and receives the signals.

A transmitter emits a high frequency signal into the ground.  This signal is reflected, refracted, and/or scattered by the materials and objects below the surface.  A receiving antenna records the signal variations and an image of the subsurface is created.  Images can be created by horizontal or vertical slices or combined into a 3-D image.
Higher frequency signals will not penetrate as far as lower frequencies, but they may create a higher resolution image.  Dry materials, like stone, are more resistive and the signal will penetrate deeper.  Moist materials, like clay, are conductive and will not reflect the signal as well creating a much shallower penetration.  Ice and snow allow for the deepest signal penetration. 

Ground penetrating radars use radar pulses to create an image of material below the surface of the ground.  The radar is nondestructive electromagnetic radiation, which is completely safe and will not harm the operator.  GPRs are used to find utility lines, diagnose structural building problems, and find buried objects.  They work on a variety of materials including rock, dirt, pavement, ice, and fresh water; they will not work in salt water.  GPRs are also called ground probing radars, ground radars, and georadars.

• Earth Science
• Engineering
• Construction
• Military
• Utilities
• Archaeology

• Geophysical Survey Systems, Inc. (GSSI)
• Mala
• Terraplus
• US Radar, Inc.