Patent ID: 9381983
Filing Date: 2016-07-05
CPC Classification: B63C,G01S

Claim Text:
1. A method of determining an absolute position of a diver, comprising: providing a dive leader unit having a geographic positioning system, such as GPS, receiver and an underwater acoustic modem configured to retransmit position coordinates of the dive leader unit under water, providing the diver with a monitoring unit comprising at least three microphones so that it is possible to detect a direction of the dive leader unit, providing synchronization between the dive leader unit and the monitoring unit to make it possible to calculate a distance from the dive leader unit to the monitoring unit, and in the monitoring unit: receiving the retransmitted position coordinates, detecting the direction of the dive leader unit, calculating the distance to the dive leader unit, and calculating the absolute position of the diver based on the retransmitted position coordinates, the direction of the dive leader unit and the distance from the dive leader unit to the monitoring unit, the method further comprising: synchronizing the system clocks of the dive leader unit and the monitoring unit through a handshake procedure, and pairing the monitoring unit to the dive leader unit to form a communication network so as to identify differences between system clocks of the dive leader unit and the monitoring unit, wherein the communication network uses a time division setup where monitoring units temporarily are assigned to a slot to be used when communicating, each slot having room for a number of data-blocks to be transmitted.