D. 'TELLUROMETER' - HYDRODIST MODEL MRB/2 



1. GENERAL 



The 'Tellurometer' microwave system of distance measurement, 

 introduced in 1957, provides distance measurements to geodetic accuracy from 

 a relatively short range to line of sight (25 miles). These measurements can 

 be made under proper conditions to an accuracy of 1 part in 30, 000. The align- 

 ment of the radio beams need be only approximate, and operation from a single 

 tower of minimum stability is practical where necessary. Problems in meas- 

 urement brought about by reflected radio energy are minimized both by the 

 relatively high frequency (10 cm band) and the specialized instrumentation 

 techniques utilized. 



A more recently developed 'Tellurometer' type system (termed 

 Hydrodist) enables a fix for a moving vessel to be obtained as a function of two 

 continuously measured ranges. The master station is located on the moving 

 vessel and the remote stations are located at known points ashore. Accuracies 

 of ± 1 .5 meters at ranges out to 40, 000 meters (25 miles) are obtained under 

 optimum conditions. 



DESCRIPTION 



The basic 'Tellurometer' distance-measuring system was developed 

 principally for the measurement of useful distances to geodetic accuracy be- 

 tween two fixed points, the master station and a remote station. Two operators 

 are required, one at each instrument. The observations are made at the master 

 station, while the operator at the remote station performs the various switching 

 operations as instructed by the master station operator. A two-way voice com- 

 munications link is built into the equipment for this purpose. An antenna with 

 a parabolic reflector is located at each instrument and is directed toward the 

 receiving instrument. A 12-volt storage battery provides the necessary power 

 for portable equipment. 



The Hydrodist system was developed from 'Tellurometer' for making 

 position measurements from a moving vessel at sea. Two master stations, 

 each with its own operator, are required aboard the moving vessel. Distance 

 measurements are continually made to each shore station (or buoys) placed at 

 known geographic positions within line-of-sight distances of the moving vessel . 

 These remote stations may be left unattended if they include a remote-controlled, 

 pattern-following auxiliary unit. 



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