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原文传递 Magnetometer Sensor Feasibility for Railroad and Highway Equipment Detection. High-Speed Rail IDEA Program.

题名：	Magnetometer Sensor Feasibility for Railroad and Highway Equipment Detection. High-Speed Rail IDEA Program.
作者：	brawner, j. mueller, k. t.
关键词：	measurement, vehicle detection, railroad detection, railroad grade crossings, warning systems, electromagnetic interference, identification systems, feasibility studies, measuring instruments, field tests, speed
摘要：	This study investigated the feasibility of using Anisotropic Magneto-Resistive (AMR) magnetometers to detect train or vehicle presence and to determine train speed for the activation of grade crossing warning systems. Laboratory, parking lot, and railroad field tests were performed using 3-axis digital AMR magnetometers for train and vehicle detection as well as speed measurement. It was determined that the sensors drift with changes in the ambient temperature. However, by periodic bias removals (auto-calibrations), the impact of these bias drifts can be eliminated. It was also determined that the detection distance for vehicles depends on the amount of magnetic material (iron, nickel, or cobalt) and varies as the inverse cubed (third) power of the distance from the sensor. Changes in the ambient electro-magnetic field such as caused by variable current power lines, are also detected with an inverse (first power) distance relationship. Hence, electromagnetic interference may travel a longer distance than a magnetic signature, depending on the magnitudes of these two signals. Overall, it was found that the 3-axis measurement capability of the AMR magnetometers permits the unique identification of different vehicles. It also permits the separation of vehicle signatures from noise signatures. Hence, these magnetometers provide an alternative, more flexible, approach for activating crossing warning systems than the current use of track circuits. / NOTE: Final rept. (Aug 2005-Jun 2006). / Supplementary Notes: Sponsored by Transportation Research Board, Washington, DC. IDEA Programs. / Availability Note: Product reproduced from digital image. Order this product from NTIS by: phone at 1-800-553-NTIS (U.S. customers); (703)605-6000 (other countries); fax at (703)605-6900; and email at orders@ntis.gov. NTIS is located at 5285 Port Royal Road, Springfield, VA, 22161, USA.
总页数：	u0724；37p
报告类型：	科技报告