Homing system and method for an autonomous underwater vehicle

A submarine homing system comprising:

• an acoustic emitter configured to emit an acoustic signal comprising at least two narrow-band tones, each narrow-band tone having a respective predetermined center frequency;
• and
• an autonomous underwater vehicle AUV comprising:
• an acoustic receiver configured to receive the acoustic signal from the acoustic emitter, and produce one or more receiver signals;
• a processor operatively connected to the acoustic receiver, the processor being configured to process the receiver signals to calculate a direction between the acoustic receiver and the acoustic emitter;
• and
• a control systerm responsive to the processor to cause the AUV to follow a desired path relative to the calculated direction between the acoustic receiver and the acoustic emitter.