Abstract
A mooring-type underwater positioning system (UPS) to measure the bag-net movements in a set-net by acoustic telemetry techniques with five transponders was reconstructed. The field experiments were conducted in Jaran Bay, Kosung, Korea on 6 October 2000 (neap tide) and 28 November 2000 (spring tide). The average UPS fixing errors of x-axis, y-axis and z-axis were less than 0.6 m, 0.8 m and 1.2 m, respectively. The longitudinal movement range, the latitudinal range and the vertical range of the bag-net at the neap tide were 3.2 m, 3.4 m and 2.1 m, respectively. At the spring tide, these ranges were 7.8 m, 7.8 m and 5.0 m, respectively. It was confirmed that the UPS system could be used for measuringa part of the bag-net movement.
