01100802

Monograph

http://onlinepubs.trb.org...ail/hsr-53final_report.pdf

This Innovations Deserving Exploratory Analysis (IDEA) 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 (3rd) 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 (1st 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.

This HSR-IDEA project was conducted by the Sensis Corporation, Seagull Technology Center, Campbell, California. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved

HSR-IDEA Project 53

English

33p

2006-6

High-Speed Rail IDEA Program Project Final Report

Final Report

Print

Figures; Photos; References (4) ; Tables (3)

Electromagnetic interference; Feasibility analysis; Field tests; Grade crossing protection systems; Laboratory tests; Magnetometer detectors; Railroad grade crossings; Speed measurement; Technological innovations; Warning systems

Innovations Deserving Exploratory Analysis (IDEA) (Program)

Activation (Warning systems); Train speed

Highways; Operations and Traffic Management; Railroads

TRIS, TRB

Jun 12 2008 1:15PM