초록 ▼

The present invention enables a vehicle navigation system to automatically compensate for odometer measurement errors due to changes in tire size and/or slip, and to avoid odometer recalibration when slip is present. These capabilities improve the accuracy and reliability of the vehicle navigation s

The present invention enables a vehicle navigation system to automatically compensate for odometer measurement errors due to changes in tire size and/or slip, and to avoid odometer recalibration when slip is present. These capabilities improve the accuracy and reliability of the vehicle navigation system. Slip of a vehicle, e.g., a loss of traction, can occur when a road is wet or covered with snow or ice. It can occur when a road is dry, and a vehicle is accelerating or decelerating rapidly. It can occur rounding a sharp corner. Because an odometer is typically hooked up to a driven wheel, the engine or transmission, there may be large sources of error in the distance estimates derived from the odometer. Utilizing conveniently derived slip signals from an anti-lock brake system (ABS) or from a traction control system (TCS), the slip of the vehicle can be accounted for, even absent a GPS signal to recalibrate the system. This allows for improved accuracy of the system which is particularly noticeable in urban environments where GPS signals may not be available.

대표청구항 ▼

1. A method for navigating a vehicle comprising the acts of:obtaining during a first time interval an odometer indication signal indicative of a distance traveled by the vehicle, a slip indication signal indicative of the slip of the vehicle, and a heading indication signal indicative of the heading

1. A method for navigating a vehicle comprising the acts of:obtaining during a first time interval an odometer indication signal indicative of a distance traveled by the vehicle, a slip indication signal indicative of the slip of the vehicle, and a heading indication signal indicative of the heading of the vehicle; converting the odometer indication signal to a first distance estimate; determining a position of the vehicle based on a known prior position, the first distance estimate obtained during said act of converting and the heading of the vehicle indications of which are obtained during said first act of obtaining; obtaining during the first time interval an external distance estimate for the vehicle from a radio navigation system; determining whether the external distance estimate includes indicia of reliability; and adjusting an odometer conversion parameter utilized in said act of converting if the external distance estimate includes indicia of reliability as determined in said second act of determining.