Methods of and systems for continually measuring the range between mobile underwater vehicles carrying acoustical signal transmitters and remotely deployed synchronized underwater acoustical receivers provided with signal processing for continually determining such range during the underwater moving of the vehicle, and for measuring acoustic underwater transmission loss, geoacoustical properties and for other purposes

A method of continually measuring the range between an acoustic undersea source and one or more hydrophone acoustic receivers deployed in the sea remotely from the source, that comprises,

• transmitting predetermined periodic acoustical signals from the source;
• time-synchronizing the transmission of such periodic signals with the receivers;
• measuring the time delay of the signal transmissions to the receivers through suitable waveform signal processing;
• determining the range from the source by the product of the sound velocity in the sea and the measured time delay;
• periodically repeating such-transmitting, measuring and determining, to enable the range to be measured in close to real time;
• and
• measuring the source sound level and measuring the pressure levels at the receiver(s) for each transmission, thereby to enable determining the undersea transmission or propagation loss in such real-time.

A system for continually measuring the range between an acoustic source integrally mounted within an unmanned or autonomous mobile undersea vehicle and one or more hydrophone acoustic receivers deployed in the sea remotely from the vehicle, the system, having, in combination,

• means for programming the vehicle to run predetermined tracks in the sea;
• the acoustic source comprising transducers for transmitting predetermined periodic acoustical signals from the source during such run;
• time-clocks for synchronizing the transmission of such periodic signals with the receivers;
• signal processing software for measuring the time delay of the signal transmissions to the receivers;
• means for determining the range from the vehicle source by calculating the product of the sound velocity in the sea and the measured time delay;
• and
• means for enabling the periodic repeating of such transmitting, measuring and determining, to enable the range to be measured in close to real time throughout the duration of the vehicle run.

A system for continually measuring the range between an acoustic undersea source and one or more hydrophone acoustic receivers deployed in the sea remotely from the source, having, in combination,

• and acoustic source comprising transducers for transmitting predetermined periodic acoustical source signals from the source;
• time-clocks for synchronizing the transmission of such periodic signals with the receivers;
• signal processing software for measuring the time delay of the signal transmissions to the receivers through suitable waveform signal processing;
• means for determining the range from the source by calculating the product of the sound velocity in the sea and the measured time delay;
• and
• calibration means for measuring the source sound level and measuring the pressure levels at the receiver(s) for each transmission, thereby to enable determining the undersea transmission or propagation loss in realtime.