A device for assisting with the detection of a sought object on the ground, said object having a first pre-determined height h, said device comprising: - a display device configured to display an image on a screen, the image being generated from echoes measured by a wave reflection imaging device, the image representing intensities of echoes generated by an observed zone of the ground under the effect of the emission of at least one wave pulse toward the observed zone of the ground, the image extending at least along a distance axis (d) representing the oblique distances (do) separating the wave reflection imaging device from reflectors that have generated the echoes, the image having a pre-determined distance resolution ρ, the display device allowing a cursor to be displayed superposed on said image on said screen, said cursor making it possible to designate at least one designated position on the image, - a human-machine interface comprising a pointer allowing an operator to move the cursor over the image at least along the distance axis (d), - a computational module configured to determine an expected length w along the distance axis (d) of an expected shadow (19, 20) projected over the image by the sought object assuming that the sought object is positioned at a designated position on the ground corresponding to the position of the observed zone associated with the position designated by the cursor, the cursor comprising at least one gauge of the expected shadow, the gauge being dimensioned and arranged so as to allow an operator to verify that a shadow projected over the image in the vicinity of the designated position has the expected length along the distance axis (d). - a display device configured to display an image on a screen, the image being generated from echoes measured by a wave reflection imaging device, the image representing intensities of echoes generated by an observed zone of the ground under the effect of the emission of at least one wave pulse toward the observed zone of the ground, the image extending at least along a distance axis (d) representing the oblique distances (do) separating the wave reflection imaging device from reflectors that have generated the echoes, the image having a pre-determined distance resolution ρ, the display device allowing a cursor to be displayed superposed on said image on said screen, said cursor making it possible to designate at least one designated position on the image, - a human-machine interface comprising a pointer allowing an operator to move the cursor over the image at least along the distance axis (d), - a computational module configured to determine an expected length w along the distance axis (d) of an expected shadow (19, 20) projected over the image by the sought object assuming that the sought object is positioned at a designated position on the ground corresponding to the position of the observed zone associated with the position designated by the cursor, the cursor comprising at least one gauge of the expected shadow, the gauge being dimensioned and arranged so as to allow an operator to verify that a shadow projected over the image in the vicinity of the designated position has the expected length along the distance axis (d).