Ground-Penetrating Radar Meets Virtual Reality Augmentation

New Surveying Method Takes the Guesswork and Delays Out of Ground Investigation.

Before taking a backhoe to an empty lot, builders need to ensure they’re not going to puncture forgotten sewage lines, expose pockets of toxic gas or damage major historical sites. Investigating the ground before digging a foundation can take months of surveying, which costs time, money and the patience of those who live near the construction site. Now, a ground-penetrating radar (GPR) technique is making this formerly time-intensive phase of construction the work of a single afternoon.

Postdoctoral student Dylan Burns wheels the cognitive ground penetrating apparatus over a paved area to obtain data on the structures beneath. (Image courtesy of Brian Jenkins.)

Researchers at the University of Vermont characterize this apparatus as a “cognitive” GPR because it not only senses underground infrastructure but also uses edge computing to build a 3D image that human eyes can easily recognize. The components work together to enhance the investigative power of this novel radar application.

Professor Dryver Huston emphasized the use of full waveform digitization in the GPR apparatus as a means of minimizing cost while keeping radiation within FCC-dictated limits. In a report made to the Vermont Transportation Agency two years prior to the current incarnation of his and Professor Tian Xia’s research, he detailed the design of a pulse generation circuit capable of producing signals that could be easily picked up by an ultrawide bandwidth (UWB) antenna. This low-energy signal production method only works over short distances. By processing the data on-site, Huston and Xia were able to take full advantage of the scalability—and low cost—of this technology.

In the circuit schematic for the pulse generator, signals from a field-programmable gate array are refined to generate Gaussian pulses that can be easily picked up by a UWB antenna. (Image courtesy of Tian Xia, Dryver Huston and the Vermont Transportation Agency.)

A simple 3D scanning smartphone app brings together all the information collected by the radar system into a map of the underground infrastructure with the help of augmented reality (AR) software used in video game development. The system is shifting from data analysis in the cloud to edge computing or processing the data close to the site where it is being collected. Rather than sending out pulses, pushing the data packet to the cloud for analysis, collecting more data and repeating for hours or days until a full map is generated, the goal is to have a surveyor looking at the map of the ground below his or her feet in real time. A team at the University of Tennessee Chattanooga, led by Professor Dalei Wu, is developing the edge computing platform to make this vision a reality.

Through AR goggles, construction workers can view an image of a pipe buried beneath sand constructed from the cognitive GPR data. (Image from video courtesy of the University of Vermont and University of Tennessee at Chattanooga.)

For more on nondestructive testing methods, check out this flexible ultrasound patch and our three part NDT overview.