Vehicle presence detection system
First Claim
1. A train presence detection apparatus for use with a level crossing warning system, the apparatus comprising:
- at least one passive magnetic detector provided at ground level or buried below ground level in between rails of a railroad track at a distance from said level crossing for detecting magnetic field disturbances caused by ferromagnetic objects passing overhead on said track;
magnetic field reversal detection means connected to said passive detector for detecting a plurality of reversals in a magnetic field detected by said passive detector and outputting a reversal signal; and
train presence analyzer means for analyzing said reversal signals and outputting a train presence output signal.
2 Assignments
0 Petitions
Accused Products
Abstract
A passive magnetic detector is provided at ground level or buried below ground level in between rails of a railroad trace at a distance from the level crossing for detecting magnetic field disturbances caused by ferromagnetic objects passing overhead on the track. Magnetic field reversals are detected in the passive detector signal. The reversal signal is analyzed and a train presence output signal is generated for controlling a level crossing gate system or other such crossing warning system. For parallel tracks, pairs of passive magnetic field detectors detect objects over each track and the reversals are analyzed to check that an inbound train does not sneak by undetected as an outbound train is leaving and passing over the same detector pair. At the level crossing, static magnetic field detectors are used to ensure that no equipment remains on the island after detecting that the moving train has left the crossing, so that the crossing gates can be safely lifted as soon as possible.
42 Citations
15 Claims
-
1. A train presence detection apparatus for use with a level crossing warning system, the apparatus comprising:
-
at least one passive magnetic detector provided at ground level or buried below ground level in between rails of a railroad track at a distance from said level crossing for detecting magnetic field disturbances caused by ferromagnetic objects passing overhead on said track; magnetic field reversal detection means connected to said passive detector for detecting a plurality of reversals in a magnetic field detected by said passive detector and outputting a reversal signal; and train presence analyzer means for analyzing said reversal signals and outputting a train presence output signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. A vehicle motion detector circuit for analyzing at least one passive magnetic field detector output signal to generate a signal indicating on which one of a plurality of lanes or tracks a vehicle is traveling and causing a disturbance in a magnetic field detected by said detector, the detector circuit comprising:
- analyzer means for analyzing said detector output signal to determine a sharpness thereof and for outputting said lane or track discriminating indicating signal, said sharpness being dependent on a proximity of said vehicle to said magnetic field detector while moving past, whereby the lane or track on which said vehicle is traveling is detected.
- View Dependent Claims (12, 13, 14)
-
15. A stationary or slow moving train presence detection apparatus for detecting an object on a railroad track at a level crossing, the apparatus comprising:
-
an array of magnetometer detectors provided at ground level or buried below ground level in between rails of said railroad track for detecting static magnetic field levels caused by ferromagnetic objects located overhead on said track at said crossing; recording means for recording, as recorded values, magnetic field level signal values from said detectors when no object is present on said track at said crossing; and train presence analyzer means for comparing signal values from said detectors to said recorded values and outputting a train presence output signal.
-
Specification