Step Frequency Time Domain Reflectometry for Distributed Temperature Sensing Navy SBIR FY2009.1 Sol No.: Navy SBIR FY2009.1 Topic No.: N091-048 Topic Title: Step Frequency Time Domain Reflectometry for Distributed Temperature Sensing Proposal No.: N091-048-0989 Firm: Intelligent Automation, Inc. 15400 Calhoun Drive Suite 400 Rockville, Maryland 20855 Contact: Devendra Tolani Phone: (301) 294-4630 Web Site: www.i-a-i.com Abstract: Intelligent Automation Inc (IAI) is partnering with Boeing to develop an innovative distributed temperatures sensor based on Electrical Time/ Frequency Domain Reflectometry. The core idea is the development of a simple, practical, yet robust electrical equivalent of Fiber Braggs Grating using thermistor based frequency tuned circuits. The step frequency Time Domain Reflectometer (TDR) is used for generating input signals using Direct Digital Synthesis (DDS). These input signals are fed into an appropriately temperature rated coaxial cable (which traverses the entire span of the cryostat to be monitored) with single ended access and minimum attenuation. On this coax cable are frequency tuned thermistor circuits that respond only to certain frequencies. The cryogenic narrow band pass filters are designed to admit only a narrow band of frequencies. Essentially at any given time the step frequency TDR interrogates only a particular thermistor element of the circuit. The use of electrical rather than optical methods allows use of materials and components that have been thoroughly tested at cryogenic temperature, reducing risk. We plan to leverage several key technologies (Time Domain Reflectometer, Step frequency Radar) developed under other ongoing programs at IAI, thus further mitigating the technical risks. Benefits: Military/Government Application(s): The purpose of the proposed work is to develop a distributed temperature sensor for large cryostats used for degaussing loops on Navy ships. The COTR has lab facility with a prototype cryogenic degaussing loop. The goal of this SBIR is to instrument the instrument that facility. The technology developed here will make superconducting degaussing more practical and facilitate transition to the fleet. NASA has also shown a keen in our proposed distributed temperature sensor technology and they can provide additional transition paths. For this project IAI is partnering with Boeing, which well positioned to service the Navy market for sophisticated instrumentation. Boeing's interest in the proposed technology is strong and is motivated by a wider range of applications than just instrumenting degaussing loops. Boeing has provided us with a detailed support letter (Attached at the end of the proposal) which lists these transition vehicles. Non-Government Application(s): Since our concept of distributed sensing using step frequency TDR is so versatile, it is not limited to temperature sensing. Any physical phenomena which cause a minor impedance change (e.g., electrical strain measurement) can potentially be measured by this technique. This opens up range of possibilities including (but not limited to) development of next generation distributed health monitoring sensors such as strain sensors. Our transition partner Boeing backs our claim by stating clearly that: "We believe that the proposed electrical approach is simpler and more practical. The proposed distributed temperature sensor can be modified to solve the strain measurement problem by replacing the thermistors by low temperature electrical strain gauges". We anticipate that by collaborating with Boeing in Phase I and Phase II, the resulting S&T effort will lead to a higher TRL level. Targeting a wider range of applications will increase the chance of follow up or contiguous funding for technology development, maturation, and a commercially viable and sustainable product. Return