Hydrographic applications of the global positioning system

Abstract

Global positioning satellite have been tested under a variety of conditions and have demonstrated exceptional accuracy. The most portable of the Phase I development equipment is the manpack/vehicle user equipment (MVUE or Manpack). The purpose of this study was to determine is a manpack is suitably accurate for coastal hydrographic surveying at scales on the order of 1:20,000. The MVUE was placed aboard the Naval Postgraduate School Research Vessel (R/V) ACANIA and operated under survey conditions in Monterey Bay, California. This objective required the testing for the manpack developed by Texas Instruments, Inc., under varying survey conditions to determine the degradation of positional accuracy. The limit of the survey scale to which the unprocessed manpack data could be employed in a real-time operation was found to be 1:80,000 and smaller by the positioning error criteria of 0.5 mm to the scale of the survey (Umbach, 1976). Application of differential techniques during the post-processing of the MVUE position data increased the limit of the survey scale to 1:40,000 using the same positioning criteria.