Underwater acoustic fixing systems

The AC Electronics Division of General Motors Corporation has established a three-dimensional acoustic tracking range on the north edge of the Santa Cruz basin, south of the Santa Barbara Channel Islands off the California coast. The Santa Cruz Acoustic Range Facility (SCARF) contains four bottom-mounted hydrophones located in 4000 feet of water. These are cabled to an underwater termination chamber at the 6O-foot depth. Additional cables lead from the chamber to the control center located on Santa Cruz Island. The system will track a target in 3 dimensions in the spherical mode using three hydrophones within a circle 25,000 feet in diameter with an rms error of less than 10 feet. In the hyperbolic mode the system will track in three dimensions over an ellipse1 5,000 feet by 5000 feet to a rms accuracy of 10 feet and an ellipse 30,000 feet by 10,000 feet for an rms error of 30 feet.