Low Frequency Radiolocation gear was used extensively during the Wakulla II expedition to enhance the accuracy of a 3D map of the extensive 300 foot (90 m) deep underwater cave system at Wakulla Springs State Park in Florida.  Careful Radiolocation work found  the position directly above 38 marked points in the spring to within one meter. The UTM coordinates of these surface points were initially determined to within 4 meters using  simple US Coast Guard DGPS gear.  Later, each surface point was Precisely located to within approximately 1cm using a combination of Real-Time Phase-Differential GPS and conventional surveying with a "Total Station".  These locations were used to correct for drift in the Inertial Navigator guidence system in the underwater Digital Wall Mapper used to create the map.