Description:
TECHNOLOGY AREA(S): Bio Medical
OBJECTIVE: The objective of this topic is to create a simulator to provide what-if scenarios to aid in developing smart combat uniform sensors and technology to record electromagnetic field activity of the war-fighter. The model will be developed for Joint use and is based on the e-textile work performed by the Services; in particular the Revolutionary Fibers and Textiles Institute located at the U.S. Armys Natick Soldier Research Development and Engineering Center (NSRDEC).
DESCRIPTION: Electro-Magnetic Fields (EMF), result from electrical currents. Within the electromagnetic (EM) spectrum, there are many frequencies radiating from humans. For instance, infrared (IR) imaging is used to detect heat signatures of humans in otherwise dark conditions. Likewise, the human body is rich in EMFs resulting from nerve firings. However, with the exception of IR, the EMFs generated from humans are weak when compared to those from external electrical devices. Having the ability to monitor a warfighters EMF at various locations could provide valuable evidence of trauma and other conditions impacting the warfighters ability to perform normal combat operations. The logical placement of such sensors is within the domain of electro-textile combat uniforms. Currently, research into smart combat uniforms continues to advance with integration of power and data. The goal of this research is to simulate monitor and capture the signal data resulting from the human body. This will simulate advanced technologies such as conductive fibers embedded in uniforms. For this to be ultimately viable, the conductive fibers need to pick up weak EMFs. Ideally, signal processing capabilities would also be available to the warfighter to digitally filter out signals of no interest (noise). This effort is focused on the EMFs indicating from the human body and being received by conductive fibers. The conductive fibers act as an antenna and capture EMFs to depict the state of the warfighter prior to injury, and use those as a base (a quiescent state). The quiescent state would then be stored using embedded processors. Upon injury and periodically thereafter, the dynamic changes of warfighter nerve impulses or other radiating signals would be captured and recorded. These records would establish a medical record of important nerve activity before, during, and following injury. At one end of the electromagnetic spectrum, infrared radiation emanating from the human body is examined at airports to detect passengers with fevers. At the other end, electrodes attached to the skin are used to record electro-cardiographs. This research seeks to explore the electromagnetic frequency range between these two extremes to see is the human body is radiating other signals that could be used to ascertain health. The efforts deliverable should rely on signals received as a method for sensing changes to the human body. The idea is the human body is the main sensor and we seek to simulate ways to electronically read the changes through the use of conductive fibers. Previous work has described using conductive fibers for antenna [4] and the potential for reading signals from the human body [5]. The research should consider unique environments such as submersion in salt water, humid, and dry environments. The effort should use an innovative approach to implement a simulator to provide a what-if assessment of current technologies for e-textiles to determine which are capable of detecting electrical signals emanating from the body without contact. Different conductive fibers are expected to receive different signals. The simulator should be extensible to model new fiber technologies as they become available. The assessments will determine size and power budgets for various technologies, along with their projected reductions. The simulations will be based on the conductive fiber combat uniform prototypes built by the Natick Soldier Research Development and Engineering Center [1].
PHASE I: Phase I will consist of a simulation using sensor materials to detect weak EMFs, possibly operating in the Nano-Tesla range. This work will build on using conductive fibers as possible sensors. That is, if a conductive fiber is vulnerable to EMI, use this vulnerability as a sensor. In particular those designs that are not used because of susceptibility to EMI will be explored as potential sensors. The simulation will help to refine how sensors, to include fibers as sensors, could be used within combat situations. It will test sensors at the technology level, specifically examining the signal processing requirements to include the sensors frequency range, power requirements, and size. The simulation will also use a history of past technical advances to predict future size reductions. That is, as the size of the sensor decreases, the resulting EMI detection capabilities will be analyzed. The expected results should point to technologies for detecting signals resulting from changes to the human body. These could be determined by contrasting the set of signals received before the event to those following the event. Success is determined if a difference can be computable. The second part of Phase I will establish a baseline for human generated EMF frequencies and field strengths. That is, identifying what set of signals are available than can be detected by various conductive fibers. In so doing, the simulator should be able to simulate using multiple conductive fiber technologies to receive different signals. In general, there are numerous man-made and other interference signals. Shielded enclosures such as those typically used to eliminate or suppress communication signals in support of TEMPEST reduction could be used to improve fidelity. A shielded enclosure or other innovative approach could be used to attenuate ambient noise and allow for accurate EMF measurements from various locations adjacent to the human subject. Various injuries and stress to the human body will be simulated to ascertain the best algorithms for determining the root causes. Specific questions to be answered in this phase are: What is the best approach for isolating human generated EMFs from background noise; What is(are) the best fiber as sensor technology(ies); How will the sensors transmit information through an e-textile data bus; Should the sensor include Digital Signal Processing circuity; and What are the limitations for EMF sensors in e-textiles?
PHASE II: In Phase II, Phase I results will be used to simulate signal transfer and processing. The simulator will use multiple sensor inputs to calculate background noise and correctly filter it out. The normal EMF will be simulated and signal processing algorithms will be developed to establish a quiescent state. That is, determining what signals normally radiate from the human host. Next, the best performing algorithm for determining root causes from Phase I will be tested. This phase may use a shielded EMF enclosure validate simulations and thereby establish correct baselines associated with physiological changes such as strenuous exercise, combined with the effects of water, heat, and cold.
PHASE III: The Phase II simulator and algorithms will be used to apply different conditions to explore their impacts on e-textile combat clothing as a base for validating of concept in Phase III. The warfighter uniform will be modeled using the NSRDEC prototypes developed to date, which include data bus and power conducting fibers. To validate the simulator, connection to a signal processor with the recommended sensor technologies from Phases I and II simulations will be tested and used to validate the simulation sensor technology and supporting algorithms. Phase III will also test exposure to chemical, biological, or nuclear threats; unknown attack sources. A key activity will be properly packaging the results so that the technology can be integrated into the e-textile combat uniforms researched out of the NSRDEC and developed with the support of PEO Solder. The resulting simulation, if successful, should help e-textile manufacturing in selecting conductive fibers best suited for detecting bodily generated EMF. This will facilitate commercial and military clothing designs that seek to integrate performance monitoring within the clothing worn.
REFERENCES:
1: Electro-Textile Garments for Power and Data Distribution, Jeremiah R. Sladea, Carole Winterhalter, Infoscitex Corporation, 295 Foster Street, Littleton, MA, USA 01460; Natick Soldier Research Development and Engineering Center, 15 Kansas St., Natick, MA, USA 01760.https://www.researchgate.net/public
2: Wearables at war: How smart textiles are lightening the load for soldiers, Trenholm, Richard; March 11, 2015; http://www.cnet.com/news/wearables-at-war-how-smart-textiles-are-lightening-the-load-for-soldiers.
3: Mehdipour, Aidin, et. al., Conductive carbon fiber composite materials for antenna and microwave applications, Radio Science Conference (NRSC), 2012 29th National, April 2013.
4: Salvado, Rita, et. al., US National Library of Medicine, Textile Materials for the Design of Wearable Antennas: A Survey, www.ncbi.nlm.nih.gov/pmc/articles/PMC3522988/
KEYWORDS: Smart Clothes, Electromagnetic Interference, Electromagnetic Fields, Wireless Sensor Networks, Electronic Textiles, Electronic Materials, Uniforms, Signal Detection
