Multifan survey system and method

A survey system for performing a multifan bathymetric survey, the survey system comprising:

• a multibeam echo sounder including a receiver and a transmitter for use with a plurality of transducers in a single projector array and a single hydrophone array;
• the projector array and the hydrophone array for use in a Mills Cross arrangement;
• the transmitter configured to generating a message including N>=3 coded message components that overlap in time and frequency;
• the message for exciting each of the projectors in the projector array;
• the message components configured to simultaneously ensonify three or more respective fans using the projector array;
• the receiver for receiving returns from the ensonified fans via the hydrophone array;
• and,
• N matched filters in the receiver, each matched filter configured to selectively detect a respective fan return out of the three or more respective fans.