DeTeC  Demining Technology Center

The radar choosen for our experiments is a SPRScan commercial system made by ERA Technology. Its sampling head is able to acquire a maximum of 195 A-scans, of 512 points each, per second (or 390 A-scans of 256 points in coarse mode) with 16 bit resolution and a maximum equivalent sampling rate of 40 GHz (25 ps time resolution). Before the A/D conversion the signal is analogically averaged (10 or 20 samples) to improve the S/N ratio and a time varying gain correction of 0.4 dB/ns is applied to partially compensate for the soil attenuation. The acquired data is buffered in two FIFOs able to store one A-scan each and is displayed in real time as a scrolling B-scan on the LCD screen of a rugged 486, 66 MHz PC.
 

A prototype resistively loaded parallel dipoles antenna has been used for our acquisitions (size: 195 x 195 x 95 mm). The pulse generator (pulse width: 200 ps, repetition rate: 1 MHz) is integrated in the antenna case to minimize losses and transmission reflections. This antenna has a nominal bandwidth of 800 MHz to 2.5 GHz, which leads to an expected resolution of less than 5 cm.