32 THE NAVY OCEANOGRAPHIC OPERATIONS PROGRAM 



to provide the geodetic support which must precede all surveying 

 of the oceans. Data collected at sea is of little value unless the 

 surveyor knows his precise position at the time of its collection. 

 Merely knowing the survey vessel's position relative to adjacent 

 land masses is no longer enough, and accurate distances and 

 directions to points on the earth's surface, often thousands of miles 

 away, must be determined. Geodetic support for ocean surveys 

 and associated projects of the Department of Defense is provided 

 by the Naval Oceanographic Office. 



In support of these surveys, extension of geodetic control into 

 the oceans is usually accomplished by the use of both long-range 

 and short-range electronic positioning systems, including 

 LORAN-C, LORAC, OMEGA, DECCA HI-FIX, and RAYDIST. 

 However, merely possessing the power supply plus the system 

 transmitters and receivers falls far short of having an accurate 

 and reliable positioning capability. The shore-based transmitters 

 must be tied geodetically to existing control points in the area 

 by established standard land surveying techniques such as 

 triangulation, trilateration, or traverse, using precise theodolites, 

 tellurometers, and electrotapes. In the remote regions where 

 many Navy surveys are conducted, finding, recovering, and eval- 

 uating control points present many problems; in many cases 

 markers for such points have been destroyed. Where previous 

 land surveys have not been conducted, a comprehensive geodetic 

 survey must be performed which includes establishing an astro- 

 nomical origin and determining deflection of the vertical values 

 to relate this remote area properly to the rest of the world. When 

 the system transmitters are positioned and the system is oper- 

 ating, it must be precisely calibrated. Following this, system 

 coordinates must be converted to geographic coordinates to be 

 overprinted on navigational charts. Users must be advised of the 

 system's capabilities and limitations. 



Among the many Department of Defense projects given geo- 

 detic support have been the Southwest Pacific Geodetic Survey, 

 the Navy's Navigational Satellite Program, the Mediterranean 

 Salvage Operation (unarmed nuclear weapon recovery off Spain) , 

 and the establishment of DEW LINE, AUTEC, and both the 

 Atlantic and Pacific Missile Test Ranges. The many field oper- 



