Detection of truck speed sensor failure using GPS
First Claim
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1. A method for detecting an error in either of a vehicle speed sensor or vehicle geographic position determining system, said method comprising the steps of:
- obtaining a first vehicle geographic position with said position determining system;
starting a timer for indicating the expiration of a predetermined period of time;
upon expiration of said predetermined period of time;
obtaining a current vehicle speed measurement from said vehicle speed sensor;
obtaining a second vehicle geographic position with said position determining system;
calculating a first distance traveled by said vehicle by multiplying said current vehicle speed measurement by said predetermined time period;
calculating a second distance traveled by said vehicle by calculating the distance between said first and second vehicle geographic positions;
comparing said first and second distances; and
indicating an error if said first and second distances are not within a predefined tolerance of one another.
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Abstract
A system (10) and method for detecting a speed sensor failure in a vehicle equipped with a geographic position determining system such as a GPS system (14). An on-board processor (12) compares vehicle travel distance calculations made using speed sensor (20) information to distance calculations performed using positional information. Discrepancies therebetween are used to indicate errors in the information provided by the speed sensor, or conversely, by the positioning system.
37 Citations
15 Claims
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1. A method for detecting an error in either of a vehicle speed sensor or vehicle geographic position determining system, said method comprising the steps of:
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obtaining a first vehicle geographic position with said position determining system; starting a timer for indicating the expiration of a predetermined period of time; upon expiration of said predetermined period of time; obtaining a current vehicle speed measurement from said vehicle speed sensor; obtaining a second vehicle geographic position with said position determining system; calculating a first distance traveled by said vehicle by multiplying said current vehicle speed measurement by said predetermined time period; calculating a second distance traveled by said vehicle by calculating the distance between said first and second vehicle geographic positions; comparing said first and second distances; and indicating an error if said first and second distances are not within a predefined tolerance of one another. - View Dependent Claims (2, 3, 4)
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5. A system for detecting an error in either of a vehicle speed sensor or a vehicle position determining system, said system for detecting being installed on said vehicle and comprising:
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a vehicle speed sensor adapted to generate an output signal indicative of an instantaneous vehicle speed measurement; a vehicle geographic position determining system, said position determining system being adapted to generate an output signal which includes a location indicative point indicative of the present geographical location of said vehicle; a first timer for determining and indicating the expiration of a first predetermined period of time; a processor adapted for receiving said speed sensor output signal and said output signal from said position determining system, said processor using said speed sensor output signal to determine a first distance value representative of the total distance traveled by said vehicle during said first predetermined period of time, said processor receiving a first location indicative point from said position determining system at the initiation of said first predetermined period of time and a second location indicative point upon the expiration of said first predetermined period of time, said processor determining a second distance value representative of the distance between said first and second location indicative points, said processor comparing said first distance value to said second distance value and generating an error output signal when said comparison is not within a predefined tolerance level; and an error indicating device coupled to said processor for receiving said error output signal and indicating an error condition. - View Dependent Claims (6, 7, 8, 9, 10, 11)
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12. A method of detecting an error in either of a vehicle speed sensor or vehicle geographic position determining system, said method comprising the steps of:
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obtaining a first vehicle geographic position with said position determining system; starting a first timer adapted to indicate the expiration of a first predetermined period of time; starting a second timer adapted to indicate the expiration of a second predetermined period of time of shorter duration than said first predetermined period of time, said second timer timing said second predetermined period of time throughout the duration of said first predetermined period of time; obtaining a current vehicle speed measurement from said vehicle speed sensor associated with each said second predetermined period of time; using said current vehicle speed measurement to calculate an incremental distance value associated with each said second predetermined period of time; and upon expiration of said first predetermined period of time; obtaining a second vehicle geographic position with said position determining system; calculating a first distance traveled by said vehicle by summing said incremental distance values; calculating a second distance traveled by said vehicle by determining the distance between said first and second vehicle geographic positions; comparing said first and second distances; and indicating an error if said first and second distances are not within a predefined tolerance of one another. - View Dependent Claims (13, 14, 15)
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Specification