severe problem, one has merely to glance at 

 Figure 7.38 which shows portions of a side 

 scan sonar record from ALUMIISAUT. Vir- 

 tually every electronic component aboard 

 the vehicle, including the scientific instru- 

 ments themselves (stereo camera system), 

 produced an interference pattern on the rec- 

 ord which partially or completely obliterated 

 the returning echoes from the sonar's trans- 

 ducers. ALUMINAUT is not alone in this 

 problem; to a greater or lesser degree all 

 submersibles exhibit electrical and/or acous- 



tic interference. Because this problem has 

 such an impact on the scientific and survey- 

 ing potential of submersibles, its nature and 

 the means of suppression, as discussed by 

 Haigh, are summarized in some detail. 



Acoustic sources of interference may be 

 mechanical, hydraulic or pneumatic in origin. 

 These are considered so basic as to constitute 

 design error. The chief consideration, there- 

 fore, is given to other types of acoustical as 

 well as magnetic and electrical interference. 

 Figure 7.39 presents their origin and nature. 



mmm 



osnACu AvotOANa sonai 



HMIJONTAl TNtUSTH 



viancAi THiutni 



7 



ST{*(0 CAMfRA SYSTEM 



TIANSPONOfR IKS 



fVfNI 

 MAtIt 



UQC 



UMINOWN 



fXAMPLES OF ELECTRONIC INTERFERENCf ON SIOC SCAN SONAR RECORDS 



Fig 7 38 Examples ol electronic interference on side scan sonar records (NAVOCEANO) 



362 



