OCR Text |
Show posters on the hill \ Wireless Site Assessment and Evaluation within a Multipath Environment in Aircraft Structures Thomas Evans, Cynthia Furse Department of Electrical and Computer Engineering Mukipaih peaks and nulls art caused b\ constructive and rtomsemc interference measured through a closed doorway f bese graphs shim the distribution nt pmver levels in a non-multipath ' environment (i.c. an artechoic chamber) and a highly mull (i.e.. a tar's passenger compartment )¦ If there is no mullipath, al! power le r are nearh the same ikiii. If there is a Jot of muHipaltung, the po Wireless Site Assessment and Evaluation within a Multipath Environment in Aircraft Structures Thomas Evans, Cynthia Furse Department of Electrical and Computer Engineering As Lging aircraft wiring has been identified as an area of critical national concern. The average age of commercial aircraft is now over 20 years. As wires age, they become brittle and are often damaged by normal and/or careless maintenance. The Center of Excellence for Smart Sensors at the University of Utah is a national leader in the development of sensors for locating faults on aging wiring and has developed the first-ever system capable of locating faults on live wires in flight. If a wire breaks, it certainly cannot be used to send the data back to the central base station to alert the pilot of the damage, so one of the important parts of this system is the communication network that can be used to communicate the information about wire health back to a central base station for the maintainer to evaluate and identify necessary repairs and their locations. This requires essentially a "cellular telephone network" within an aircraft. One of the critical components of any wireless system design is developing a model of the communication channel - the path, reflections, attenuation, and interference - that the wireless signal will experience within the plane. This is then used to design a functional communication system. The method for testing the wireless channel is to place a transmitter in one location and move the receiver throughout the other locations of interest, recording the power of the fields. The mathematical statistical model is then based on these measurements which tells how strong the main line of sight path is (generally rather weak) compared to the extensive multi-path from reflections at metallic and other solid surfaces. Actual testing at Hill Air Force Base has not yet begun, though permission to run the tests is expected in the next few weeks. Consequently, work this summer has been focused on perfecting test methods as well as a visit to HAFB to plan where test equipment will be placed within the aircraft. Once we obtain permission, we will be measuring the communication channel within several different types of military aircraft, and will develop appropriate mathematical channel models to be used in the wireless system design. |