TOTEM Projector Suite Calibrations


  1. Fleming, R.A.G.
Corporate Authors
Defence R&D Canada - Atlantic, Dartmouth NS (CAN)
The TOwed Torpedo Emulator (TOTEM) system was recently developed under contract from Defence Research and Development Canada - Atlantic (DRDC Atlantic) by Ultra Electronics Maritime Systems Incorporated (UEMS) and Brooke Ocean Technology (BOT) to provide a towable system for producing acoustic signatures to emulate those of torpedoes. TOTEM emulates torpedo signatures from a suite of four different underwater sound projectors and is capable of projecting sound omnidirectionally from 120 Hz to 10 kHz and directionally from 20 kHz to 32 kHz. TOTEM was successfully trialed in October of 2006, but there remained a requirement for complete characterization of the transmitting voltage responses and directivity patterns of projectors installed in the tow-body. In March 2007, transmitting voltage responses and directivity patterns at various depths and orientations were measured at the Acoustic Calibration Barge (ACB). Results showed that the in-situ transmitting voltage response (TVR) of the omnidirectional projectors was generally 3 to 6 dB below expected performance, except in the 240 Hz to 350 Hz band. There were no marked changes noted as a result of changing depth. These response curves’ shapes showed good agreement with finite element design models, except for resonance frequency shifts due to inter-projector interaction. There was also a 10 dB drop in output at 430 Hz. This drop in expected performance was shown to be caused by interactions within the tow-body.

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Report Number
DRDC-ATLANTIC-TM-2007-095 — Technical Memorandum
Date of publication
01 Nov 2007
Number of Pages

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