b. Range and Accuracy 



(1) Usable service range: 55 - 135 nautical miles. 



(2) Approximate accuracy of range measurement: 1 : 50,000 feet, 

 depending upon the position of the mobile unit relative to the 

 shore station transmitters. 



(3) Accuracy of LOP: dependent upon absolute magnitude of errors 

 and angle at which hyperbolic arcs intersect. Area of uncertainty 

 is negligible when angles of intersection are between 30 and 150°. 



REFERENCES 



LOR AC - Seismograph Service Corp. , Tulsa, Oklahoma - Radio Aids to 

 Maritime Navigation and Hydrography. SoP. 39 - Article supplied, 

 April 1960. 



G. Leifson, "Hyperbolic Positioning Systems for Hydrographic Surveys," 

 U.S. Hydrographic Office, International Hydrographic Review , May 1953. 



Edward J. Crossland, "LORAC: What It is and How It Works, " Seismograph 

 Service Corp., Tulsa, Oklahoma. Reprinted from Philco Tech Rep Division 

 Bulletin, March 1952. 



125 



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