transmitting antennas were precisely positioned in many locations 

 to support worldwide air and sea navigation. 



Magnetic data are utilized by Navy in support of antisubmarine 

 warfare (ASW) programs and in fire control, to update of world 

 magnetic anomaly charts at 5-year intervals, and for military and 

 civilian navigation. In FY '73 approximately 57,000 track miles of 

 airborne vector magnetic data were collected in the southern 

 hemisphere for worldwide magnetic mapping purposes. In addition, 

 48,000 miles of airborne scalar magnetic data were collected in 

 cooperation with the Naval Research Laboratory with the objective 

 of using the magnetic data for mapping major geophysical features. 

 The Geomagnetic Airborne Survey System (GASS) was installed on 

 the Project MAGNET aircraft and is now in operational use. GASS 

 uses an inertial navigation system to provide references for deter- 

 mining vector components of the magnetic field. Increased accuracy 

 in positioning (to 1 nautical mile worldwide based on a tie to the ma- 

 jor navigational systems) and a vast improvement in dip and 

 declination measurements have been achieved with GASS. A new 

 prototype magnetic field chart was field tested with excellent cor- 

 relation between the predicted and observed background noise 



The Navy Project MAGNET aircraft has been equipped with a new instrument 

 system to improve the accuracy of geotnagnetic surveys. 



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