METHODS AND SYSTEMS FOR MAKING A GPS SIGNAL VITAL
First Claim
1. A method for making the derived position from a global positioning system (GPS) receiver mounted onboard a train or other vehicle, vital, the method comprising the steps of:
- receiving GPS data from a plurality of satellites at a first GPS receiver located off the train, the first GPS receiver being at a first known position;
determining any corrections necessary for each of the plurality of satellites by comparing the positions reported by the satellites to the first known position;
receiving additional GPS data at a second GPS receiver located off the train, the second GPS receiver being at a second known location which may be the same or different from the first known location;
validating the corrections calculated using the GPS data from the first GPS receiver using the additional GPS data from the second GPS receiver;
if the corrections are valid, transmitting a message including the corrections to the train; and
using the corrections and GPS data from a third GPS receiver to determine the position of the train.
3 Assignments
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Accused Products
Abstract
Position reports from GPS receivers can be made vital through a variety of techniques including relative differential GPS corrections and a technique in which a train traveling on a fixed path is provided with a database that includes positions on fixed paths or data from which positions on fixed paths can be determined. Position reports from GPS receivers located on the vehicle are compared to the positions of the fixed paths in the database. If the distance from the position reported by the GPS receiver to the nearest point on the nearest fixed path is greater than the stated accuracy of the GPS receiver, the position report is discarded or other corrective action is taken. A second technique involves cross-checking position reports from two GPS receivers separated by a known distance, preferably mounted on a single vehicle. Still other techniques may be used.
138 Citations
24 Claims
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1. A method for making the derived position from a global positioning system (GPS) receiver mounted onboard a train or other vehicle, vital, the method comprising the steps of:
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receiving GPS data from a plurality of satellites at a first GPS receiver located off the train, the first GPS receiver being at a first known position; determining any corrections necessary for each of the plurality of satellites by comparing the positions reported by the satellites to the first known position; receiving additional GPS data at a second GPS receiver located off the train, the second GPS receiver being at a second known location which may be the same or different from the first known location; validating the corrections calculated using the GPS data from the first GPS receiver using the additional GPS data from the second GPS receiver; if the corrections are valid, transmitting a message including the corrections to the train; and using the corrections and GPS data from a third GPS receiver to determine the position of the train. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A train control system comprising:
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a first GPS receiver located off the train, the first GPS receiver being at a first known position; a second GPS receiver located off the train, the second GPS receiver being at a second known position; a third GPS receiver mounted on the train; a first processor in communication with the first and second GPS receivers, the first processor being configured to perform the steps of determining any corrections necessary for GPS data received from each of a plurality of satellites at the first GPS receiver by comparing the positions reported by the satellites to the first known position; validating the corrections in the correction message at the second GPS receiver; if the corrections are valid, transmitting a message including the corrections to train; a second processor in communication with the third GPS receiver;
the second processor being configured to perform the steps ofusing the corrections and position information from the third GPS receiver to determine the position of the train. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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Specification