A high-stability dual-chip GPR for cooperative target probing

A complete Ground Penetrating RADAR (GPR) system, including emitter, receiver and processing circuit, has been assembled with minimum part numbers for a compact, low power solution aimed at probing passive cooperative targets acting as sub-surface sensors. The high timing stability of the recorded signal needed for phase analysis is met by clocking all circuits, including the stroboscopic timer, with a quartz disciplined reference signal. We demonstrate 21 ps timing stability when measuring the long term evolution of two echoes separated by 300 ns, consistent with the ability to measure with 1 K resolution surface acoustic wave transducers designed as GPR cooperative sensors, dedicated to temperature sensing in the current demonstration. The solution takes advantage of some of the latest microcontroller peripherals including a timer with 217 ps resolution, for an equivalent time sampling up to 4.6 GS/s. Wireless measurement at a range of 70 cm is demonstrated through air, with a signal to noise ratio allowing for far range measurement in dielectric sub-surface media.