Three-dimensional buried mine positions from arbitrary radar surface scans

A method is presented for the rapid evaluation of object positions in three dimensions from sets of Ground Penetrating Radar (GPR) range measurements. The scans need not form a regular raster: it is necessary only that the sc ans follow one or more continuous paths. The method extends by the ideas re ported by Windsor and Capineri (1998) where the 'ringing' signal from the r eflected object signal in any one scan is correlated with that of its neigh bours to follow the ringing signal and so produce a set of range values cov ering ail the surface positions where adequately well correlated signals we re observed. Randomly chosen sets of three range values are then used to so lve analytically for the thr ee co-ordinates of the mine position consisten t with these ranges. A rapid estimate of the mine position and its statisti cal uncertainty is built tip from numerous selections front the complete su rface raster scan. A three-dimensional plot of the results is developed to give an intuitive image of the estimated buried object position and the rel ative uncertainty: The method is demonstrated using measurements recorded a nd made available by the DeTeC group at EPFL, Lausanne, Switzerland. A typi cal anti-personnel land mine buried at 100 mm nominal depth in sand was eva luated to be at 105 +/-23 mm. The x and y co-ordinates were positioned to w ithin better than 32 mm in less than five seconds computation time on a PC.