An imaging radar equipment devoted to the detection of buried objects has been developed for the French National Police (CREL DGPN). This radar, so called "Microwave Tomographic Imaging Tool" (MTIT), offers quasi-real time capabilities for analysing ground cross-sections of 1 meter depth by 1 meter width. In comparison with all existing GPR equipment, the MTIT is composed of an array of sensors. Adequate ground discriminator data processing is used to prepare properly data before applying spectral diffraction tomographic algorithms. Such algorithms have been already assessed on previous equipment designed by SUPELEC and realized by SATIMO for the detection of metallic bars in concrete structures. This paper presents results obtained from in situ measurements. The robustness of the results with respect to parasitic movements and vibrations has been assessed.