Patent ID: 9151833
Filing Date: 2015-10-06
Classification: A01K,G01S,G01V

Abstract:
1. A method for determining distance from a reference point to at least two sensor modules ( 10 , 20 ) when these have the same distance to the reference point and all of which are located under water, wherein the sensor modules ( 10 , 20 ) are in signal connection with each other in that they comprise means for sending and receiving acoustic signals, and wherein the reference point comprises a hydrophone ( 30 ) with means for receiving acoustic signals from the sensor modules ( 10 , 20 ), the method comprising the following steps: a) sending an acoustic signal from the first sensor module ( b) sending an acoustic signal from the second sensor module ( c) measuring in the first sensor module ( d) sending an acoustic signal, comprising the said time T e) measuring arrival times and travel times of received acoustic signals sent from the first and second sensor module ( f) determining the difference in distance from the reference point to each of the sensor modules ( g) adjusting and positioning the distance to the sensor modules ( h) logging over time values of received acoustic signals within a set uncertainty for calculated differences for distances approaching zero; i) determining distance from the reference point to the at least two sensor modules (