Apparatus for generating a heading signal for a land vehicle
First Claim
1. An apparatus for generating data regarding a heading of a land vehicle, comprising:
- a plurality of sensor means for generating respectively a plurality of independent direction signals including heading information indicating a heading of the land vehicle, said plurality of independent direction signals respectively including errors having essentially independent spectral characteristics; and
processing means, responsive to said plurality of independent direction signals, for generating an estimated heading of the land vehicle includingmeans, responsive to a filter control signal, for filtering a subset of said plurality of independent direction signals according to the spectral characteristics of the errors included in at least one direction signal included in the subset; and
means for generating said filter control signal in response to a parameter indicating an estimated error magnitude of the errors in at least one of the direction signals in the subset.
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Accused Products
Abstract
Disclosed is an apparatus generating accurate data regarding the heading of a land vehicle as it travels over terrain having changing conditions. The apparatus includes a first sensor means, such as a differential odometer, generating data regarding the relative direction of the vehicle. Also included is a second sensor means, such as a flux gate compass, for generating data regarding the absolute direction of the vehicle relative to the earth. The relative directional data and the absolute directional data are combined in a means for generating accurate data regarding the heading of the vehicle. A means for reducing errors reflected in signals generated by the sensors is provided to insure the accuracy of the output.
188 Citations
29 Claims
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1. An apparatus for generating data regarding a heading of a land vehicle, comprising:
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a plurality of sensor means for generating respectively a plurality of independent direction signals including heading information indicating a heading of the land vehicle, said plurality of independent direction signals respectively including errors having essentially independent spectral characteristics; and processing means, responsive to said plurality of independent direction signals, for generating an estimated heading of the land vehicle including means, responsive to a filter control signal, for filtering a subset of said plurality of independent direction signals according to the spectral characteristics of the errors included in at least one direction signal included in the subset; and
means for generating said filter control signal in response to a parameter indicating an estimated error magnitude of the errors in at least one of the direction signals in the subset. - View Dependent Claims (2, 3)
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4. An apparatus for generating data regarding a heading of a land vehicle, comprising:
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a plurality of sensor means for generating respectively a plurality of independent direction signals including head information indicating a heading of the land vehicle, wherein said plurality of said independent direction signals includes errors; and processing means, responsive to said plurality of independent direction signals, for generating an estimated heading of the land vehicle including filter means, responsive to a filter control signal, for reducing the effects of said errors; and means for generating said filter control signal in response to a parameter indicating an estimated error magnitude of a subset of said plurality of direction signals. - View Dependent Claims (5, 6)
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7. An apparatus for generating data regarding a heading of a land vehicle, comprising:
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first sensor means for generating a first direction signal including heading information indicating a heading of the land vehicle and errors having primarily first spectral characteristics; second sensor means for generating a second direction signal including heading information indicating a heading of the land vehicle and errors having primarily second spectral characteristics that are different from said first spectral characteristics; and processing means, responsive to said first and second direction signals, for generating an estimated heading of the land vehicle, including first means for combining said first direction signal and said second direction signal to generate a combined error signal essentially isolating said first and second errors from said heading information; filter means for filtering said combined error signal according to filter characteristics approximating said first spectral characteristics to generate a filtered error signal including essentially said second errors; and second means for combining said filtered error signal and said second direction signal to offset said second errors and thereby provide the estimated heading. - View Dependent Claims (8)
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9. An apparatus for generating data regarding a heading of a land vehicle, comprising:
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first means for generating a relative direction signal having a heading component indicating a heading direction for the land vehicle relative to a prior heading of the land vehicle and an error component; second means for generating an absolute direction signal having a heading component indicating a heading direction for the land vehicle relative to the earth and an error component; and processing means, responsive to said absolute direction signal and said relative direction signal, for generating an estimated heading of the vehicle, including filter means, responsive to a filter control signal, for filtering said error components in said absolute direction signal and said relative direction signal to reduce said error components; and means for generating said filter control signal in response to a parameter indicating an estimated magnitude of the error component in at least one of said absolute direction signal and said relative direction signal. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. An apparatus for generating data regarding a heading of a land vehicle, comprising:
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first means for generating a relative direction signal having a heading component indicating a heading direction for the land vehicle relative to a prior heading of the land vehicle and an error component; second means for generating an absolute direction signal having a heading component indicating a heading direction for the land vehicle relative to the earth and an error component; and processing means, responsive to said absolute direction signal and said relative direction signal, for generating an estimated heading of the vehicle, including filter means, responsive to a filter control signal, for filtering high frequency errors from said absolute direction signal and low frequency errors from said relative direction signal; and means for generating said filter control signal in response to a plurality of parameters indicating an estimated accuracy of said second means and said first means.
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25. An apparatus for generating data regarding a heading of a land vehicle, comprising:
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first means for generating a relative direction signal having a heading component indicating a heading direction for the land vehicle relative to a prior heading of the land vehicle and an error component; second means for generating an absolute direction signal having a heading component indicating a heading direction for the land vehicle relative to the earth and an error component; and processing means, responsive to said absolute direction signal and said relative direction signal, for generating an estimated heading of the vehicle, including first means for combining said relative direction signal and said absolute direction signal to generate a combined error signal indicating the difference between said relative direction signal and said absolute direction signal; filter means for filtering relatively high frequency errors from said combined error signal to generate a filtered error signal; and second means for combining said filtered error signal and said relative direction signal to generate an estimated heading of the land vehicle.
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26. In a vehicle navigation system for automatically tracking a motor vehicle movable over a given area identified by a map, an apparatus for generating an estimated heading of the motor vehicle, comprising:
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first means for generating a relative direction signal including heading information indicating a heading direction of the motor vehicle relative to a prior heading of the motor vehicle and including first errors; second means for generating an absolute direction signal including heading information indicating a heading direction for the motor vehicle relative to the earth and including second errors, said second means including compass means for generating compass heading data indicating the heading of the motor vehicle relative to the earth, means for providing a map data base including entries, each identifying a street segment and a predicted heading of a motor vehicle on the street segment, means, in communication with said compass means and said means providing a map data base and responsive to a control signal, said compass heading data or a predicted heading identified in a map data base entry, for supplying said absolute direction signal, and means, for supplying said control signal; first combining means for subtracting said relative direction signal from said absolute direction signal to generate a combined error signal; filter means, responsive to a filter control signal, for filtering said combined error signal to essentially cancel said second errors and generate a filtered error signal, said filter means including means for generating said filter control signal in response to at least one parameter indicating the estimated magnitude of at least one of said first and second errors; and second combining means for adding said filtered error signal to said relative direction signal to essentially cancel said first errors in said relative direction signal to generate the estimated heading of the motor vehicle.
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27. An apparatus for generating an estimated heading of a land vehicle, comprising:
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first means for generating a relative direction signal having a heading component indicating a heading direction for the land vehicle relative to a prior heading of the land vehicle and an error component; second means for generating an absolute direction signal having a heading component indicating a heading direction for the land vehicle relative to the earth and an error component; processing means, in communication with the first means and the second means, for generating the estimated heading of the land vehicle including means, responsive to a parameter, for assigning weights to the relative direction signal and the absolute direction signal; means for combining the relative direction signal and the absolute direction signal according to the assigned weights, and means for supplying the parameter in response to an estimated magnitude of the error component of one of said absolute direction signal or relative direction signal. - View Dependent Claims (28)
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29. An apparatus for generating data regarding a heading of a land vehicle, comprising:
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a plurality of sensor means for generating respectively a plurality of independent direction signals including heading information indicating a heading of the land vehicle, said plurality of independent direction signals respectively including errors having essentially independent characteristics; and processing means, responsive to said plurality of independent direction signals, for generating an estimated heading of the land vehicle including means responsive to a filter control signal for filtering a subset of said plurality of independent direction signals according to the characteristics of the errors including in at least one direction signal included in the subset; and
means for genrating said filter control signal in response to a parameter indicating a selected characteristic of errors in at least one of the direction signals in the subset.
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Specification