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Low Cost Persistent Environmental Measurement System


TECHNOLOGY AREA(S): Battlespace 

OBJECTIVE: Develop an air-launched persistent ocean environment measurement system that is capable of gathering and transmitting water column information at a low cost per profile. 

DESCRIPTION: In order to properly model sensor performance, accurate year-round ocean environment data is required. Currently either a ship is deployed to make profile measurements or an expendable buoy is launched from an airborne platform to make a single profile measurement. Both of these methods are costly, on the order of thousands of dollars per measurement. A persistent, profiling system is required to gather high-density measurements of the ocean environment. If a single system can perform hundreds of profiles over the course of many months, the cost per profile would be on the order of tens of dollars vs the current thousands of dollars. The Navy is well equipped to air deploy A-sized buoys anywhere in the world and therefore the profiling system will need to be rugged enough and of the proper form factor to be certified for airborne buoy launching systems. In general, the envelope of the system cannot exceed 4 7/8 inches in diameter and 36 inches in length, and the system must weigh less than 40 pounds. An example of the launch envelope and environmental factors for an existing air-launched A-sized buoy can be found in Reference 1. Due to the diverse nature of the Navy’s sensor systems, a variety of environmental measurements are required, and therefore a modular approach should be taken when considering the incorporation of multiple instruments into the profiling vehicle. The profile measurements currently of high interest are temperature, pressure, salinity, and diffuse attenuation coefficient. The depth profile, from near surface to 1,000 feet, measurement of interest is directional acoustic background noise, in the range of a few Hertz to a few kilo-Hertz. However, the priorities and needs will evolve over time and will require a flexible architecture so that individual sensors can be replaced with minimal non-reoccurring expenses. Finally, the data taken by the profiling vehicle will need to be recovered remotely, and using Iridium or another worldwide communication system, processed and delivered to the Navy. A web-based methodology would help keep the per profile cost to a minimum. 

PHASE I: Develop and demonstrate a system concept for an air-launched, persistent ocean environment measurement system that can remotely deliver profile measurements from near surface to 1000 feet to the Navy. Identify technological and reliability challenges of the design approach, and propose viable risk mitigation strategies. Develop modular measurement approach to ensure current and future flexibility. The Phase I effort will include the development of prototype plans for Phase II. 

PHASE II: Design, fabricate, and test a prototype system and demonstrate open-water measurement capability with at least two different measurement types based on the design from Phase I. Work with the Navy to certify the prototype design for air-launch capability [Ref 1]. 

PHASE III: Produce multiple copies of the low-cost, persistent measurement system; produce multiple copies of the system with sensor variants; conduct in-situ testing and deliver data products. There are several potential commercial applications for this technology. The commercial fishing industry could use this tool to track ocean conditions favorable to the type of fish to be netted. The climate and weather prediction industry could use this tool to track evolving ocean conditions, a key factor for their analyses. 


1: MIL-S-81478C Military Specification for AN/SSQ-57A

2:  "Next-Generation Unmanned Undersea Systems." Defense Science Board Report, Oct 2016.

KEYWORDS: Profile; Buoy; Persistent; Ocean Measurement; Water Column; Modular 


Brian Concannon 

(301) 342-2034 

Aaron Meldrum 

(301) 342-0398 

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