Ground penetrating radar Posted on April 9th, 2010 by Anna Versluis

This blog is by Gustavus student Ethan Degner as part of his Remote Sensing of Environment class.

(Graphic from http://www.gprdata.com/.)

When you think of remote sensing, you probably think of satellites and planes taking pictures of the earth’s surface. You probably don’t think of what lies beneath ground level, and might not even care, but knowledge of what lies beneath has many academic and practical applications.

Ground penetrating radar (GPR) provides a nonintrusive means of exploring underground features. Like any radar, it is an active form of remote sensing, which means it emits its own signal and records the strength and variation of that signal as it is reflected back to the sensor. Although some forms of GPR collect data aerially, ground-based GPR is often more practical. Ground-based GPR allows for a stronger, more direct signal and finer spatial resolution—benefits that outweigh the hassle of physically moving the sensor over the coverage area in most applications.

Applications of GPR cover a large range of disciplines. It can be used to examine bedrock composition and depth, groundwater levels, and ancient river beds. It has aided in the exploration of geological formations, including possible oil fields, under sandy deserts and the Antarctic tundra. This technology has benefitted archaeology by finding new excavation sites and mapping sites prior to complete excavations.

GPR is not solely an academic technology. Forensics teams use it to locate buried evidence. With its help, the mining industry can better map tunnels and boreholes, reducing the risk of cave-ins. Urban planners use GPR regularly to map existing sewage ducts, water mains, and power and gas lines. It has even been used in post-conflict areas, such as Kosovo and Vietnam, to locate landmines in former minefields.

GPR may seem like an obscure branch of remote sensing, but it is certainly an important one. With its continued advancement, GPR will become more useful and less costly, and its applications will likely expand to new fields and disciplines.