REDUNDANT, SELF-DETERMINISTIC, FAILSAFE SENSOR SYSTEMS AND METHODS FOR RAILROAD CROSSING AND ADJACENT SIGNALIZED INTERSECTION VEHICULAR TRAFFIC CONTROL PREEMPTION
Railroad crossing object detection systems and methods include radar sensors detecting object presence, speed and heading in a different manner. A controller compares signal outputs from the different sensors to provide traffic control preemption signals and self-diagnose sensor problems. The sensor devices may include an ultra-wideband (UWB) impulse radar device and at least one reflective device providing failsafe object presence detection and object non-presence detection in redundant fashion with at least a second sensor device such as a side-fired radar device.
1 . An object detection system for a rail grade crossing island comprising:
a crossing island detection system; and
a first pair of radar sensors at a first location spaced from the crossing island and independently operable from the crossing island detection system, the first pair of radar sensors including a first radar sensor and a second radar sensor independently operable from the first radar sensor, the second radar sensor operable according to a different detection technique than the first radar sensor, and each of the first radar sensor and the second radar sensor operable in combination to detect a presence, speed and heading of a train advancing toward the crossing island in a first direction or away from the crossing island in a second direction opposite to the first direction; and
at least one controller configured to compare an output of the first radar sensor, the second radar sensor, and an output of the crossing island detection system to assess a health of the object detection system, and to determine an error condition for any of the first radar sensor, the second radar sensor, and the crossing island detection system.
2 . The object detection system of claim 1 , wherein the at least one controller is further configured to output at least one preemption signal to a traffic controller for a roadway intersection for vehicle traffic adjacent to but separate from the railroad grade crossing.
3 . The object detection system of claim 2 , wherein the controller is further configured to provide a terminate track clearance signal.
4 . The object detection system of claim 1 , wherein the crossing island detection system comprises a track circuit, and wherein the first location is outside an operating range of the track circuit.
5 . The object detection system of claim 1 , wherein the crossing island detection system comprises a non-track circuit detection system.
6 . The object detection system of claim 1 , further comprising:
a second pair of radar sensors at a second location spaced from the crossing island and independently operable from the crossing island detection system and the first pair of radar sensors, the second pair of radar sensors including a third radar sensor and a fourth radar sensor independently operable from the third radar sensor, the fourth radar sensor operable according to a different detection technique than the third radar sensor, and each of the third radar sensor and the fourth radar sensor operable in combination to detect a presence, speed and heading of the object advancing in the first direction or the second direction; and
the controller further configured to compare an output of the third radar sensor and the fourth radar sensor to an output of the first radar sensor and the second radar sensor to assess a health of the object detection system and to determine an error condition for any of the first radar sensor, the second radar sensor, the third radar sensor, and the fourth radar sensor.
7 . The object detection system of claim 6 , wherein the detected speed information from one of the first and second pairs of radar sensors may be used to calculate an arrival time of the train at the crossing island to assess the health of the object detection system.
8 . The object detection system of claim 6 , wherein the detected speed information from one of the first and second pairs of radar sensors at the first location or the second location may be used to calculate an arrival time of the train at the other of the first location or the second location to assess the health of the object detection system.
9 . The object detection system of claim 1 , wherein the first radar sensor comprised an ultra-wideband (UWB) impulse radar device.
10 . The object detection system of claim 9 , wherein the ultra-wideband (UWB) impulse radar device is operable to detect at least one fixed radar target at the first location.
11 . The object detection system of claim 10 , wherein the at least one fixed radar targets comprise an active reflector device or a passive reflector device.
12 . The object detection system of claim 10 , wherein the at least one fixed radar target includes at least one rail of a railroad track.
13 . The object detection system of claim 10 , wherein the at least one fixed radar targets includes a first fixed radar target and a second fixed radar target allowing the ultra-wideband (UWB) impulse radar device to distinguish between different trains on different railroad tracks.
14 . The object detection system of claim 9 , wherein the second radar sensor comprises a side-fired, dual-beam radar device.
15 . The object detection system of claim 14 , wherein the first and second pairs of radar sensors are continuously operable to assess a presence and a non-presence of a train to assess the health of the object detection system.
16 . An object detection system for a rail grade crossing island comprising:
a first pair of radar sensors at a first location spaced from the crossing island, the first pair of radar sensors including a first radar sensor and a second radar sensor independently operable from the first radar sensor, the second radar sensor operable according to a different detection technique than the first radar sensor, and each of the first radar sensor and the second radar sensor operable in combination to detect a presence, speed and heading of a train advancing toward the crossing island in a first direction or away from the crossing island in a second direction opposite to the first direction;
a second pair of radar sensors at a second location spaced from the crossing island and independently operable from the first pair of radar sensors, the second pair of radar sensors including a third radar sensor and a fourth radar sensor independently operable from the third radar sensor, the fourth radar sensor operable according to a different detection technique than the third radar sensor, and each of the third radar sensor and the fourth radar sensor operable in combination to detect a presence, speed and heading of the object advancing in the first direction or the second direction; and
at least one controller configured to compare an output of the first radar sensor, the second radar sensor, the third radar sensor, and the fourth radar sensor to determine an error condition for any of the first radar sensor, the second radar sensor, and the crossing island detection system.
17 . The object detection system of claim 16 , wherein the first radar sensor is an ultra-wideband (UWB) impulse radar device operable to detect at least one fixed radar target at the first location.
18 . The object detection system of claim 17 , wherein the second radar sensor comprises a side-fired, dual-beam radar device.
19 . The object detection system of claim 16 , wherein the at least one controller is further configured to output at least one preemption signal to a traffic controller for a roadway intersection for vehicle traffic adjacent to but separate from the railroad grade crossing.
20 . The object detection system of claim 16 , wherein the first and second pairs of radar sensors are continuously operable to assess a presence and a non-presence of a train to assess the health of the object detection system.