Abstract: A method of localizing signals utilizing auto-correlation functions and cross correlation functions includes: collecting data at a plurality of input channels; filtering the data collected from the plurality of input channels in order to identify a primary signal; identifying at least two lags and at least one reference lag in a function of the data; and estimating relative travel times of the data.

Abstract: An acoustic tomography telemetry system and method allowing spatially averaged ocean temperatures to be measured in real-time. The system includes autonomous acoustic sources mounted on subsurface moorings and receivers that are either suspended from drifting surface buoys or cabled to shore. The telemetry method largely eliminates, in real-time, corruption of acoustic travel times due to wander of the source's mooring by shifting the start times of tomographic transmissions. Corrections to source wander are obtained without expending battery energy over and above that used in conventional tomography experiments. Standard techniques are used to correct clock errors at the source in real-time.

Abstract: A technique for the non-intrusive position determination of one or more natural or artificial acoustic transmitters (S1, S2, S3) in marine or terrestrial environments by processing data from five or more receivers (R1, R2, R3, R4, R5) distributed in the area. The data processing includes cross correlation (24) of receiver data to determine differences in acoustic data travel times (MTTD) and tomographic reconstruction (16) to determine transmitter position as well as receiver position (42), wind or current (40) and sound speed or temperature fields (44) and errors (41) associated with all of the above. Accuracy can be greatly enhanced by use of calibration transmissions at receiver or other known or unknown position locations. Position and wind, sound speed and error fields may conveniently be displayed by computer generated maps (18, 20, 22, 43).