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Dive Helmet Communication System

Description:

The current system being used is analog circuits (circa 1960's) with components to match. The communication components are susceptible to moisture and handling damage. Thus the existing communication system has reduced intelligibility in the varying noise levels of the current helmet. The diver helmet currently used by Navy divers (Kirby Morgan KM 37NS) has documented high noise levels from the breathing system with a circa 1960's communication system (analog on copper wire). This is a challenging communication environment which is complicated when using helium mixed gas (squeaky voice) and/or at depth (compressed air). Breathing air maximum operating depth is 190 feet seawater (fsw) and is 300 fsw for helium-oxygen mixes. Either breathing medium may be used in water temperatures as low as 37°F, or as low as 28°F if the helmet is used with the hot water shroud and a hot water supply. In addition, at water temperatures below 40°F, the diver will be dressed in either a variable volume dry suit or a hot water suit. Additionally, the diver community has high incidence of noise induced hearing loss (high frequency). An ideal communication system would use modern, digital signal processing, with matched microphones and speakers (actuators) to overcome these challenges and the feedback that occurs in the current analog system. All required components must be included in the system for improved diver (helmet) and topside communications. The system shall be able to frequency compensate to keep incoming signals in the optimal voice range for divers and correct for topside signals. The new system must be robust enough to handle the moisture/salt in a marine diving (90% humidity) scenario and the inherent rough handling of diver equipment. The system should also include the capability for noise monitoring and use of fiber optic signal umbilical lines in the future (i.e. accommodate the use of fiber optic cables and the reduction of copper wire in the umbilical lines). The system must work in the current noise levels of 94 to 97 dBA, which are noise hazardous (reference 1) and compromise current communications. ANSI S3.2-2009 (R2014) (Method for Measuring the Intelligibility of Speech over Communication Systems) would be an appropriate means of evaluation using the modified rhyme test. ANSI S3.2-2009 (R2014) includes factors that affect the intelligibility of speech. The new system must reduce the noise feedback loop in the helmet, producing high noise levels at the diver's ear, which increases the noise exposure. The goal is to reduce noise levels below 85 dBA. PHASE I: Determine the feasibility of developing and constructing communication technologies to provide clear communications between divers and the topside station. Develop a detailed design for a diver communication system that can meet the performance and the constraints listed in the equipment description for the Kirby Morgan KM37NS dive helmet in reference 2. Similar commercial system is shown in reference 3. Currently approved communications systems are listed in reference 4. The technical manual (N00178-04-D-4012/HR06) is reference 5. Perform design trade-offs to provide initial assessment of concept performance for topside, bottom-side, multiple divers and umbilical components and be suitable for the marine environment. The dive helmet communication system must consider forward fit and back fit and be reported in the Phase I Final Report. System concept must address pressure changes which occur in the helmet. System may utilize frequency shifting to deal with gas density and/or mixed gas. System concept must also address diver utility (i.e. ear equalization) if considered. Phase I includes the initial layout and capabilities description to build the unit in Phase II. Current topside design factors are Space: 10" x 9" x 14.5"; Weight: 22lbs; Power: 110/220 VAC 50/60 Hz (autosensing) or internal/external battery 12 VDC. PHASE II: Produce dive helmet communication system prototype hardware based on Phase I concept design for evaluation. Finalize the prototype design and validate improved communications at topside station. Also, validate improved communications under while breathing air (maximum operating depth is 190 feet seawater (fsw) and is 300 fsw for helium-oxygen mixes. Either breathing medium may be used in water temperatures as low as 37°F, or as low as 28°F if the helmet is used with the hot water shroud and a hot water supply. In addition, at water temperatures below 40°F, the diver will be dressed in either a variable volume dry suit or a hot water suit. Install developed prototype in a Kirby Morgan KM 37NS dive helmet. The developer will use its own helmet during Phase II. Speech intelligibility tests shall be performed to confirm the communication improvements. Deliver two full prototype dive helmet communication system kits for testing and evaluation at a location chosen by the US Navy. PHASE III: Construct production units suitable for certification for the Approved for Navy Use (ANU) List and develop marketing plans for a broad range of customers. Kits shall include all hardware required for modification of helmets, topside equipment, installation, operations and maintenance procedures.

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