Diver navigation system

Abstract

A diver navigation system which provides reliable position information to able a diver to locate and when required repair existing underwater devices such as cables, leg moorings and the like. The diver navigation system comprises a synchronous range-range navigation system operating on a repeating timing cycle, which is accurately duplicated in a master transmitter, a slave transmitter and a receiver. Within the master and slave transmitter the timing cycle is subdivided into two equal approximately one second subcycles, the first subcycle being for the master transmitter and the second subcycle being for the slave transmitter. The master transmitter sends out a tone burst signal at the beginning of the first subcycle and the slave transmitter sends out a tone burst signal at the beginning of the second subcycle. Each tone burst signal, in turn, comprises a 34 kilohertz signal followed by a 32 kilohertz signal each of which has a time period of approximately one millisecond. The tone bursts signals travel through water and arrive at the receiver delayed by a time period which is a function of range, temperature, pressure and the velocity of sound. The detection times for travel of the tone burst signals from the master transmitter and the slave transmitter are converted to range data by the receiver using the velocity of sound. The range-range data is then converted to X and Y coordinates by the receiver using a baseline length which is the distance between the master transmitter and the slave transmitter.