Train navigator with integral constrained GPS solution and track database compensation
First Claim
1. A method for navigation in a system including railway track having a plurality of track irregularity classes with a quantitative value associated with each class and a railway vehicle for movement along the railway track having a navigation system for determining railway vehicle position along the railway track, the navigation system including a database having at least a geometric track model contained therein, the navigation system also including inertial components for measuring heading and variations thereof and acceleration and variations thereof and a satellite responsive GPS for providing geopositional data, comprising the steps of:
- establishing an a-priori stochastic model of actual navigation errors and an a-priori stochastic model of a measurement aiding process;
effecting a Kalman type filtering of error variables to create estimated track database errors constrained by the track irregularity class; and
implementing substantially real-time feedback of estimated track database errors for correcting the geometric track model contained in the database for subsequent use for navigation upon the railway track.
2 Assignments
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Accused Products
Abstract
The present invention provides a new set of algorithmic solutions to accommodate track inaccuracy information in track databases. Navigation and measurement aiding processes are defined by a stochastic mode relative to a moving rail frame defined so that it is aligned with the heading of the compensated track database at the current along track-position. Filtering generates long and short wavelength track alignment disturbances commensurate with track grade to compensate for track database errors; a stochastic error model is defined as the difference between the deterministic implementation and the actual stochastic processes Bayesian estimation of the error variables is implemented via a digital Kalman filter with the navigation, database, and measurement errors removed by subtracting the filter estimates.
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Citations
6 Claims
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1. A method for navigation in a system including railway track having a plurality of track irregularity classes with a quantitative value associated with each class and a railway vehicle for movement along the railway track having a navigation system for determining railway vehicle position along the railway track, the navigation system including a database having at least a geometric track model contained therein, the navigation system also including inertial components for measuring heading and variations thereof and acceleration and variations thereof and a satellite responsive GPS for providing geopositional data, comprising the steps of:
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establishing an a-priori stochastic model of actual navigation errors and an a-priori stochastic model of a measurement aiding process; effecting a Kalman type filtering of error variables to create estimated track database errors constrained by the track irregularity class; and implementing substantially real-time feedback of estimated track database errors for correcting the geometric track model contained in the database for subsequent use for navigation upon the railway track. - View Dependent Claims (2)
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3. A method for rail track database compensation in a system including railway track having a plurality of track irregularity classes with a quantitative value associated with each class and a railway vehicle for movement along the railway track having a navigation system for determining railway vehicle position along the railway track, the navigation system including a database having at least a geometric track model contained therein, the navigation system also including inertial components for measuring heading and variations thereof and acceleration and variations thereof and a satellite responsive GPS for providing geo-positional data, comprising the steps of:
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establishing an a-priori stochastic model of actual navigation errors and an a-priori stochastic model of a measurement aiding process; effecting a Kalman type filtering of error variables to create estimated track database errors constrained by the track irregularity class; and implementing substantially real-time feedback of estimated track database errors for correcting the geometric track model contained in the database for subsequent use for navigation upon the railway track. - View Dependent Claims (4)
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5. A method of simultaneous navigation and rail track database correction in a system including railway track having a plurality of track irregularity classes with a quantitative value associated with each class and a railway vehicle for movement along the railway track having a navigation system for determining railway vehicle position along the railway track, the navigation system including a rail track database having at least a geometric track model contained therein, the navigation system also including inertial components for measuring heading and variations thereof and acceleration and variations thereof and a satellite responsive GPS for providing geo-positional data, comprising the steps of:
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establishing an a-priori stochastic model of actual navigation errors and an a-priori stochastic model of a measurement aiding process; effecting a Kalman type filtering of error variables to create estimated track database errors constrained by the track irregularity class; and implementing substantially real-time feedback of estimated track database errors previously presented for navigation upon the railway track. - View Dependent Claims (6)
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Specification