Researchers at the Military University of Technology, Poland, have documented a new approach to creating low-cost ground-penetrating radar (GPR) devices — using off-the-shelf open source HackRF software-defined radios.
"Utilising the software-defined radio (SDR) technique is very common for developing ground penetrating radar (GPR) prototypes," researchers Jacek Jendo and Mateusz Pasternak explain, "[but] low-cost SDRs neither allow phase difference estimation between transmitter (Tx) and receiver (Rx). Consequently, direct exploitation of cheap SDRs for GPR is inaccessible."
Inaccessible, but not impossible: The pair successfully created a functional ground-penetrating radar based on a pair of open source HackRF boards — sub-$100 half-duplex software-defined radios with spectrum coverage and maximum transmission power "sufficient of most GPR applications" which proved cheaper than buying a single full-duplex rival — by adding an extra calibration step to remove the need for phase differential measurements.
"These results demonstrate that GPR prototype based on low-cost SDR is achievable," Jendo and Pasternak conclude of their work. "Suggested configuration and calibration enable real data gathering and permit interpretable imaging of simple subsurface structures to be produced. The described approach will allow researchers without access to expensive devices a rapid introductory analysis of implemented GPR or other remote sensing signal processing algorithms."