Sezack 



The navigation suit will furnish attitude and attitude rate data 

 as provided by gyrocompasses, a vertical gyro and rate gyros. A dead 

 reckoning plotter will present a visual display of the submersible 's 

 motion in a horizontal plane from data furnished by the attitude in- 

 dicators and a relative velocity indicator or from the doppler navi- 

 gator. The doppler navigator will also furnish high accuracy rate 

 and position data during the mating operation. A beacon navigation 

 system which will operate with two or more transponders, deployed on 

 the ocean bottom, will augment the dead reckoning capabilities of 

 the submersible. 



The ship control system will be a" hybrid analog-digital system 

 which will receive rate commands from the central processor or the 

 human operator depending on the operational mode selected. In the 

 cruise mode it will control the submersible in three degrees of 

 freedom, however, for mating or inspection operations the necessary 

 six degree-of- freedom control will be maintained. In order to reduce 

 the burden on the operator, optional combinations of manual and auto- 

 matic control modes will be available. Since an uncoupled response 

 will be available in each of the six degrees-of-freedom, the operator 

 can elect to maneuver the submersible in one degree of freedom 

 manually while the remaining five degrees of attitude and displace- 

 ment are held to their last commanded displacement. 



The central processor will be a digital computer with two 

 functional sections, a general purpose section and a digital dif- 

 ferential analyzer section. The general purpose section will be 

 used for low iterative random in time programs and the digital dif- 

 ferential analyzer section will be used for high iterative continuous 

 in time programs. The processor will service navigation, sonar, com- 

 munication and ship control subsystems to provide attitude, dead 

 reckoning, status, alarm and control functions for submersible 

 operation. 



The sonar suit will consist of horizontal and vertical obstacle 

 avoidance sonars, an altitude and depth sonar and a short range 

 sonar which will be used in mating operations. With the profusion 

 of sonar units on the submersible it has been called a sonic 

 Christmas tree. The multifold approach developed to minimize sonic 

 cross talk is as follows: 



Spatial separation - The transducers are distributed over the avail- 

 able surface of the vehicle and their beam patterns are directed in 

 a manner that will cause minimal interference and still serve their 

 intended purpose efficiently. 



Functional separation - An operational plan has been devised which 

 will ensure that only those sonars required for a specific part of 

 the mission will be used. When not required those sonars will be 

 secured. 



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