Precision acoustic positioning with the aidjex acoustic bottom reference system

The AIDJEX Acoustic Bottom Reference System was built by InterOcean for precise tracking of ice station movement. It was operated for two months at the AIDJEX camp approximately 300 miles north of Pt. Barrow, Alaska in the spring of 1972. The system proved capable of determining position with an error of 5 to 10 meters RMS at distances to 18 km and water depth of 3800 meters. An array of 6 acoustic transducers is used to interrogate a bottom transponder. The acoustic travel times are fed to a digital computer which calculates position in real time. The system automatically computes the position of the array elements before each transponder interrogation. The field results include observations of hydrophone movement, and some notes on acoustic propagation in the deep Arctic Ocean under the ice.