US Patent 7447116 Dynamic underwater position tracking of small objects

A system, method and program product for tracking the depth of small objects in which a transmitter is connected to a fishing line. The transmitter includes a sensor for measuring water pressure and transmits the pressure measurements to a receiver at a location remote from said transmitter. A signal processing unit is connected to the receiver and converts the transmitted pressure measurements into depth measurements. A display displays the depth measurements in real time showing the depth of the transmitter. The signal processing unit may include a wireless system for transmitting the depth measurement to a wireless display device associated with the fishing line to which the transmitter is connected.