Abstract: Paper presents initial results o laboratory tests of the sonar selected as a short range tool for an underwater vehicle. It is intended for bottom located object search and identification. To evaluate sonar imaging capability expressed by its resolution, several parameters were investigated. First group of parameters regards the sonar itself, while the second regards an object material and dimensions and shape. Their cross-influence was investigated for different distances from hydrophone to an object of interest and different hydrophone elevation angles. Experiments were performed in a shallow water laboratory tank.