Position correction method for vehicle navigation system
First Claim
1. A method for determining a current vehicle position in a vehicle navigation system having a map data base, the method comprising the steps of:
- storing a first vehicle position;
moving the vehicle from the first vehicle position;
sensing an external signal while moving the vehicle;
detecting a change in the external signal caused by the presence of a landmark;
examining the map data base to find a most likely landmark position corresponding to the change in the external signal; and
updating the current vehicle position to the most likely landmark position.
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Accused Products
Abstract
A vehicle navigation system is used to determine the absolute position of a vehicle with improved accuracy on freeways or rural highways. First, the system stores a known vehicle position in its memory. As the vehicle moves away from the known position, the system uses a variety of means to sense external signals. These means include satellite transmission receivers and magnetic compasses. When a change in the external signals occurs, the system recognizes the presence of a landmark which can then be used to set the vehicle'"'"'s position. To accomplish this, the system'"'"'s data processor searches a map data base, attempting to fix the position of the sensed landmark with respect to the initially stored known position. When the system identifies the most likely landmark, the position of the vehicle is then reset to that position.
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Citations
26 Claims
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1. A method for determining a current vehicle position in a vehicle navigation system having a map data base, the method comprising the steps of:
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storing a first vehicle position; moving the vehicle from the first vehicle position; sensing an external signal while moving the vehicle; detecting a change in the external signal caused by the presence of a landmark; examining the map data base to find a most likely landmark position corresponding to the change in the external signal; and updating the current vehicle position to the most likely landmark position. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. Apparatus for determining a current vehicle position in a vehicle navigation system having a map data base, the apparatus comprising:
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a memory for storing a first vehicle position; a sensor for sensing an external signal while the vehicle moves; and processing means coupled to the map data base, the memory and the sensor, the processing means comprising; means for detecting a change in the external signal caused by the presence of a landmark; means for examining the map data base to find a most likely landmark position corresponding to the change in the external signal; and means for updating the current vehicle position to the most likely landmark position. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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Specification