A laser detection and ranging device for detecting an object under a water surface, the laser detection and ranging device having a laser transmitter being configured to modulate a laser beam by a binary pseudo-random coding sequence to obtain a modulated laser beam, and to transmit the modulated laser beam towards the water surface, a laser detector for detecting a reflected laser beam, the reflected laser beam forming a reflected version of the transmitted laser beam, and a processor for detecting the object under the water surface upon the basis of the reflected laser beam.