Automatic determination of traffic signal preemption using GPS, apparatus and method
First Claim
Patent Images
1. A method for implementing traffic signal preemption of a signalized intersection using GPS information in which approach tracks to the intersection are created and programmed in a computer for defining a geometric area for preemption qualification, the method of setting up an approach track comprising;
- traversing an approach with a GPS receiver/processor and a specially programmed first computer;
while traversing the approach, periodically obtaining GPS position information and storing it in the first computer as a line of positions;
deriving from a set of the stored positions a geometric area containing the set of stored positions and defining a qualified approach track;
transferring to and storing the geometric area in a selected coordinate system in a second computer, which is part of an intersection subsystem, programmed to designate the geometric area as defining a space in which an otherwise qualified vehicle may qualify for preemption; and
further comprising;
for each approach for which a qualified approach track has been set up, programming in the intersection computer a selected time period defining a programmed time of arrival (PTA) for the approach;
periodically calculating from the GPS derived data the time period for arrival of the vehicle at the intersection, defining a periodic vehicle estimated time of arrival (VETA) for the vehicle;
establishing as at least one further qualification for preemption for the vehicle that upon a comparing step, the VETA has satisfied a predetermined relationship to the PTA;
comparing the VETA and the PTA; and
sending a preemption request signal to the traffic controller requesting preemption if the predetermined relationship is satisfied and any other qualifications for preemption have been satisfied.
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Accused Products
Abstract
For qualification for traffic preemption an area is defined and if the vehicle is in the area it can obtain preemption. The vehicle'"'"'s position is determined, in one embodiment, by use of differential GPS.
203 Citations
51 Claims
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1. A method for implementing traffic signal preemption of a signalized intersection using GPS information in which approach tracks to the intersection are created and programmed in a computer for defining a geometric area for preemption qualification, the method of setting up an approach track comprising;
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traversing an approach with a GPS receiver/processor and a specially programmed first computer; while traversing the approach, periodically obtaining GPS position information and storing it in the first computer as a line of positions; deriving from a set of the stored positions a geometric area containing the set of stored positions and defining a qualified approach track; transferring to and storing the geometric area in a selected coordinate system in a second computer, which is part of an intersection subsystem, programmed to designate the geometric area as defining a space in which an otherwise qualified vehicle may qualify for preemption; and
further comprising;for each approach for which a qualified approach track has been set up, programming in the intersection computer a selected time period defining a programmed time of arrival (PTA) for the approach; periodically calculating from the GPS derived data the time period for arrival of the vehicle at the intersection, defining a periodic vehicle estimated time of arrival (VETA) for the vehicle; establishing as at least one further qualification for preemption for the vehicle that upon a comparing step, the VETA has satisfied a predetermined relationship to the PTA; comparing the VETA and the PTA; and sending a preemption request signal to the traffic controller requesting preemption if the predetermined relationship is satisfied and any other qualifications for preemption have been satisfied. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for traffic signal preemption of a signalized intersection having a traffic controller and the intersection having at least one approach which is desired to have preemption available;
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wherein there is an intersection subsystem comprising; a programmed computer; a radio receiver; a signal circuit from the program controlled computer to the traffic controller; and wherein there is a vehicle subsystem comprising; a GPS receiver/processor; a programmed computer; and a radio transmitter; the intersection computer having stored in it a geometric area defining a qualified approach track for each approach for which preemption is to be available the qualified approach track having left and right boundaries and a far boundary further from the intersection and a near boundary closer to the intersection; the method comprising; the vehicle subsystem periodically receiving GPS signals and deriving therefrom position, speed and direction information for the vehicle; the vehicle subsystem transmitting periodic position, speed and direction information of the vehicle to the intersection subsystem; the intersection subsystem determining if the vehicle is within an approach track and is traveling toward the intersection; and for each approach for which a qualified approach track has been set up, programming in the intersection computer a selected time period defining a programmed time of arrival (PTA) for the approach; programming the intersection computer to periodically determine the time period for arrival of the vehicle at the intersection, defining a vehicle estimated time of arrival (VETA) for the vehicle; establishing as at least one further qualification for preemption for the vehicle that upon a comparing step by the intersection computer, the VETA has satisfied a predetermined relationship to the PTA; in the intersection computer, comparing the VETA and the PTA; and sending a preemption request signal to the traffic controller requesting preemption if the predetermined relationship is satisfied, the vehicle is an approach track and is traveling toward the intersection and any other qualifications for preemption have been satisfied; terminating the preempt request signal when the vehicle passes a selected point. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22)
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23. A method for traffic signal preemption of a signalized intersection having a traffic controller and the intersection having at least one approach for which it is desired to have preemption available using differential GPS comprising;
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setting up the intersection by (i) installing a GPS receiver antenna at a known point, as part of an intersection subsystem which has; a differential GPS receiver/processor reference station; an intersection computer; a radio receiver and transmitter; a signal circuit to the traffic controller; (ii) storing in the intersection computer in a coordinate system a geometric area defining an approach track for each approach for which it is desired to have preemption available, the approach track having a far boundary further from the intersection, a near boundary closer to the intersection and left and right boundaries; and (iii) conducting a self-survey to determine the known point for the differential GPS receiver/processor reference station; operating the system with qualified vehicles having a vehicle subsystem comprising; a GPS receiver/processor for differential operation; a vehicle computer; a radio receiver and transmitter; by; (a) the intersection subsystem periodically transmitting differential GPS information including pseudorange correction terms; (b) the vehicle subsystem periodically receiving the GPS data transmitted by the intersection subsystem and applying the pseudorange correction terms to its GPS data to determine corrected GPS data; (c) the vehicle subsystem sending corrected GPS derived position, speed and direction information to the intersection subsystem; (d) the intersection subsystem determining if the vehicle is within an approach track; (e) the intersection subsystem sending a preemption request signal if the vehicle is within an approach track and is traveling toward the intersection and satisfies any other qualifications for preemption; (f) terminating the preempt request signal after the vehicle has passed a point; and further wherein the intersection computer has stored in it a programmed time of arrival (PTA) for a vehicle for each approach track and a vehicle on an approach track periodically calculating its time of arrival at the intersection (VETA) and comparing the VETA with the PTA against a predetermined relationship and establishing as a qualification for preemption that the relationship is satisfied. - View Dependent Claims (24, 25, 26, 27, 28, 29)
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30. An apparatus for traffic signal preemption comprising;
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a set-up system comprising a computer specially programmed to create an approach track along an approach to an intersection; a vehicle subsystem comprising; a GPS receiver and processor for receiving GPS signals and processing the signals for transmission; a transmitter for sending position, speed and direction information derived from the GPS signals to an intersection subsystem; an intersection subsystem comprising; a receiver for receiving the information sent from the vehicle subsystem; a computer programmed estimated time of arrival of the vehicle at the intersection (VETA); said computer having stored therein a selected programmed time of arrival (PTA) for the approach track; said computer being programmed to compare the VETA and the PTA against a preselected comparison relationship; said computer being programmed to send a preemption signal if the comparison so permits and any other qualification requirements are met.
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31. A method for traffic signal preemption for a vehicle approaching a signalized intersection having a traffic signal controller using a system comprising, in the vehicle, a vehicle subsystem comprising a location, speed and direction sensor, a programmed computer and a radio transmitter and at the intersection an intersection subsystem, the intersection subsystem comprising a programmed computer, a radio receiver, a signaling circuit to the traffic signal controller comprising;
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for each approach to the intersection for which it is desired to permit preemption, placing in the programmed computer memory of the intersection subsystem a selected time period defining a programmed time of arrival (PTA) for the approach; for a vehicle traveling the approach toward the intersection using the location, speed and direction sensor, periodically determining the time period for its arrival at the intersection, defining a vehicle estimated time of arrival (VETA) for the vehicle; establishing as at least one qualification for preemption for the vehicle that upon a comparing step by the intersection subsystem programmed computer, the VETA has satisfied a predetermined relationship to the PTA; periodically comparing the VETA and PTA; sending a preemption request to the traffic signal controller requesting preemption if said predetermined relationship is satisfied and any other qualifications for preemption have been satisfied. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39)
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40. A method for traffic signal preemption for a vehicle approaching a signalized intersection comprising;
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for each approach to the intersection for which it is desired to permit preemption selecting a time period defining a programmed time of arrival (PTA) for the approach; for a vehicle traveling the approach toward the intersection, periodically determining the time period for its arrival at the intersection, each such determination defining a vehicle estimated time of arrival (VETA) for the vehicle at the intersection; establishing as at least one qualification for preemption for the vehicle that the VETA satisfy a predetermined relationship to the PTA defining a PTA-VETA relationship; comparing the VETA at selected periodic determinations thereof with the PTA to determine if the PTA-VETA relationship has been satisfied; upon the PTA-VETA relationship being satisfied and any other requirements for preemption qualification being satisfied, implementing a preemption procedure which puts the intersection signals in a specified preemption condition for the vehicle. - View Dependent Claims (41, 42, 43, 44, 45, 46, 47, 48, 49)
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50. A traffic preemption apparatus for traffic signal preemption for a vehicle approaching a signalized intersection having a traffic signal controller comprising;
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an intersection subsystem comprising; a programmed computer having stored in it an approach track for each approach to the intersection for which preemption is desired, and having stored in it a selected time period (PTA) for each such approach; a radio receiver to receive signals from a vehicle subsystem; and a signal circuit to the traffic signal controller to send requests; and a vehicle subsystem comprising; a GPS receiver/processor; a programmed computer; and a radio transmitter; the vehicle subsystem sending GPS derived position, speed and direction information to the intersection subsystem where the intersection computer computes a time of arrival of the vehicle at the intersection (VETA) and is programmed to compare the PTA and the VETA and if a specified programmed relationship is satisfied, and any other qualifications are satisfied, to cause the signal circuit to send a request for preemption to the traffic signal controller. - View Dependent Claims (51)
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Specification