levels. During the first quarter of FY '74, 40,000 miles of airborne 

 scalar magnetic data were collected as part of the Navy Cooperative 

 Marine Science Program with Iceland. During FY '74, the remainder 

 of 80,000 track miles of magnetic data will be collected in this area by 

 the MAGNET aircraft. 



These data are used to improve the performance of the inertial 

 navigation system. A total of 1,037,841 point gravity observations 

 were delivered to the DOD Gravity Library in St. Louis, Mo. 

 Deflections and geoid heights were computed for 135,000 points on a 

 global basis. Nine vertical deflection charts were produced. Over 

 540,000 sea gravity observations covering U.S. continental shelves 

 were forwarded to the U.S. Geological Survey (USGS) for use in 

 evaluating offshore gas and oil potential. All unclassified data will 

 continue to be forwarded to the National Geophysical and Solar 

 Terrestrial Data Center, Environmental Data Service, National 

 Oceanic and Atmospheric Administration (NOAAl. 



All gravity systems include their own special-purpose computers 

 to filter the data digitally. New gravity systems are being tested 

 which provide an output for the Eotvos correction. The Eotvos 

 correction provides the means of accounting for platform movement 

 with respect to the earth's rotation and is used to improve survey 

 results in areas of poor navigation. FY '74 plans call for a 

 continuation of the FY '73 rate of collection at the same density and 

 with approximately the same amount of areal coverage. Calculations 

 of vertical deflection and undulations of the geoid for about 90,000 

 points over the entire world are planned. 



The Harbor Survey Assistance Program(HARSAP] is intended to 

 generate and develop the capabilities of foreign countries to conduct 

 limited port and coastal hydrographic survey operations and 

 prepare preliminary charts. NAVOCEANO personnnel train foreign 

 civilian and military personnel in hydrographic techniques and the 

 maintenance and use of equipment. This past winter, eight Latin 

 American students participated in a 7-week hydrographic survey 

 training course held at the Inter-American Geodetic Survey (lAGS) 

 headquarters in the Panama Canal Zone. Six hydrographic surveys 

 were completed in the past year, and five countries are continuing 

 surveys with technical assistance and equipment supplied by the 

 NAVOCEANO. Twelve new, or new editions of, charts have been 

 produced as a result of smooth sheets furnished by HARSAP 

 countries. The program is continuing on a slightly expanded scale 

 during FY '74. 



During FY '73, a special coastal survey was conducted in Bermuda. 

 Meanwhile, coastal surveys were conducted in the Republics of the 

 Phillipines and Korea by the USNS '"hauvenet. During the first half 

 of FY '74 the USNS Chauvenet continued the Korean survey and will 



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