Patent ID: 8305841

Claim:
A method for determining the topography of a seafloor, the method comprising: sequentially transmitting a plurality of respective first pulses of first signals of a predetermined first frequency towards respective first portions of the seafloor, sequentially receiving backscattered first signals resulting from backscattering of the first signals of the respective first pulses from the seafloor, sequentially transmitting a plurality of respective second pulses of second signals of a predetermined second frequency towards respective second portions of the seafloor, sequentially receiving backscattered second signals resulting from backscattering of the respective second signals of the second pulses from the seafloor, and storing data representative of the received backscattered first and second signals referenced to data representative of the locations of the corresponding first and second portions of the seafloor for facilitating preparation of an image of the topography of the seafloor, wherein each second pulse is transmitted between two consecutive first pulses, the time duration between each second pulse and the next following first pulse is determined as a function of the maximum time-of-flight of the first signals of a previous first pulse from the time of transmission thereof to the time of reception of the corresponding backscattered first signals, and the time duration between each first pulse and the next following one of the first and second pulses is determined as a function of the maximum time-of-flight of the first signals of one of the previous first pulses from the time of transmission thereof to the time of reception of the backscattered first signals.