HIGHLY ACCURATE HYDROGRAPHIC SURVEYS USING DIFFERENTIAL GPS

HYDROGRAPHIC SURVEYS REQUIRE A HIGH LEVEL OF ACCURACY FOR T THE VESSEL POSITION AND ATTITUDE. THE POSITION ACCURACY CAN BE PROVIDED BY THE GPS SYSTEM USING DIFFERENTIAL TECHNIQUES,WHILE THE ATTITUDE CAN BE PROVIDED EITHER BY INCLINOMETERS OOR BY THE GPS COMBINED WITH INTERFEROMETRIC TECHNIQUES. THISSTUDY WILL ESTABLISH THE FEASIBILITY OF SUCH A SYSTEM, DE DEVELOP THE NECESSARY ALGORITHMS AND SIMULATE THEM ON TAU'S EXISTING, HIGH FIDELITY, NAVSTAR GPS SIMULATION. THE DESIGNPROCESS WILL INCLUDE TRADEOFF ANALYSES AS WELL AS A APPLICATION-TAILORED SATELLITE SELECTION ALGORITHMS AND ADA ADAPTIVE NAVIGATION PROCESSOR/KALMAN FILTER. PROMISING COMMERCIAL APPLICATIONS INCLUDE HARBOR NAVIGATION, SEISMIC SURVEYS, OFFSHORE OIL DRILLING, FISHING AND PLEASURE BOATING. THE POTENTIAL COMMERCIAL APPLICATION AS DESCRIBED BY THE AWARDEE: THE SOON-TO-BE RELEASED LATEST ISSUE OF THE FEDERALRADIO NAVIGATION PLAN MAKES IT CLEAR THAT GPS WILL E EVENTUALLY REPLACE MOST CURRENT RADIO NAVIGATION SYSTEMS. THE DOD IMPLEMENTATION OF SELECTIVE AVAILABILITY MAKES IT FOR DIFFERENTIAL TECHNIQUES TO BE DEVELOPED TO MEET THE CIVILIAN COMMUNITY REQUIREMENTS. MARINE USERS IN PARTICULAR WOULD GREATLY BENEFIT FROM DIFFERENITAL GPS SINCE THE REQUIREMENTS ARE THE TOUGHEST, ESPECIALLY FOR HARBOR NAVIGATION, OFFSHORE DRILLING AND SEISMIC SURVEYING. IT IS TO BE ANTICIPATED THAT MOST CIVILIAN MARINE USERS WILL BE EQUIPPED WITH GPS RECEIVERS, ESPECIALLY IF, AS IS CURRENTLY CONTEMPLATED, USER EQUIPMENT PRICES DROP SHARPLY. IN THIS CASE, HYDROGRAPHIC SURVEYS OBTAINED USING DIFFERENTIAL GPS WILL BE VERY USEFUL TO USERS (E.G., FISHERMEN) NAVIGATION WIWITH GPS SINCE REPEATABILITY WILL BE ENHANCED BY THE SYSTEM'S SIMILARITY. THE DEVELOPMENT OF AN OFFSHORE D DIFFERENTIAL GPS CAPABILITY WILL CERTAINLY FIND SUPPORT IN TTHE OIL COMMUNITY. AS FOR THE FEDERAL GOVERNMENT, THE DEVELOPMENT OF DIFFERENTIAL TECHNIQUES IS NECESSARY IF THE GPS SYSTEM IS TO BE ACCEPTED AS A PRIMARY RADIO NAVIGATION SYSTEM IN LIGHT OF THE SELECTIVE AVAILABILITY ISSUE.