Accession Number : ADA115588


Title :   Time Difference Survey System (TDSS).


Descriptive Note : Final rept.,


Corporate Author : COAST GUARD RESEARCH AND DEVELOPMENT CENTER GROTON CT


Personal Author(s) : Sedlock, A J ; Milne, T J ; Lewicki, J P


Full Text : http://www.dtic.mil/get-tr-doc/pdf?AD=ADA115588


Report Date : Apr 1981


Pagination or Media Count : 152


Abstract : A primary concern of the U.S. Coast Guard is the development of a system of using Loran=C to enable vessels to accomplish precision navigation in harbors, harbor entrances (HHE), and restricted waterways. The need for this system is especially great during periods of low visibility or when more conventional aids to navigation are not available. A visual survey method is the basic approach for a Loran-C Time Difference (TD) grid survey in restricted waterways. The shipboard visual navigation approach relates the surveyed Time Differences (TD's) to the world of the mariners. The results is a set of waypoints (i.e., intersection of two visual ranges) measured in TD's which relate to the actual location of channel edges, shoals, buoys, and other aids to navigation. This report describes the Time Difference Survey System (TDSS) which was developed at the U.S. Coast Guard R&D Center to accurately and efficiently measure, record, and process the TD information. (Author)


Descriptors :   *LORAN , HARBORS , CHANNELS(WATERWAYS) , SURFACE NAVIGATION , PRECISION , GRIDS(COORDINATES) , TIME , SURVEYS , MEASUREMENT , DATA PROCESSING , COMPUTER PROGRAMS


Subject Categories : Underwater and Marine Navigation and Guidance


Distribution Statement : APPROVED FOR PUBLIC RELEASE