VEHICLE POSITIONING BY MAP MATCHING AS FEEDBACK FOR INS/GPS NAVIGATION SYSTEM DURING GPS SIGNAL LOSS
First Claim
1. A vehicle positioning method for a navigation system established on a smartphone with use of vehicle sensors, comprising the following steps of:
- integrating, by using a processor, an inertial navigation system (INS) incorporating vehicle sensors with a map and navigation system implemented on a smartphone with use of an integration Kalman filter;
producing vehicle'"'"'s position estimates by the INS based on the acceleration and angular rate measurements from the vehicle sensors;
producing position estimates indicating an absolute position of the vehicle by the map and navigation system which receives GPS satellite signals;
detecting whether the estimated vehicle position has reached an entry point of a tunnel or has reached a point before the entry point of the tunnel by a predetermined threshold distance;
when the estimated vehicle position has reached said either one of points, immediately starting a map matching operation for matching a current vehicle position with a road link of the tunnel derived from a map database; and
performing a Kalman filter processing by the integration Kalman filter on the position estimates of the INS and the current vehicle position obtained by the map matching operation thereby correcting errors caused by the vehicle sensors.
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Abstract
A method and apparatus of vehicle positioning uses map matching as feedback for an integrated navigation system where a map and navigation system is coupled with an inertial navigation system (INS) using low-precision vehicle sensors when the vehicle passes through a tunnel or other area suffering from GPS signal loss. The method and apparatus operates to detect whether the vehicle has reached an entry point of a tunnel, and if so, immediately starts a map matching operation to match the current vehicle position with a road link of the tunnel. The current position determined by the map matching operation is feedbacked to an integration Kalman filter thereby correcting errors caused by the vehicle sensors. The method and apparatus resumes the normal navigation operation including GPS navigation as soon as it detects that the vehicle is out of the tunnel.
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Citations
20 Claims
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1. A vehicle positioning method for a navigation system established on a smartphone with use of vehicle sensors, comprising the following steps of:
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integrating, by using a processor, an inertial navigation system (INS) incorporating vehicle sensors with a map and navigation system implemented on a smartphone with use of an integration Kalman filter; producing vehicle'"'"'s position estimates by the INS based on the acceleration and angular rate measurements from the vehicle sensors; producing position estimates indicating an absolute position of the vehicle by the map and navigation system which receives GPS satellite signals; detecting whether the estimated vehicle position has reached an entry point of a tunnel or has reached a point before the entry point of the tunnel by a predetermined threshold distance; when the estimated vehicle position has reached said either one of points, immediately starting a map matching operation for matching a current vehicle position with a road link of the tunnel derived from a map database; and performing a Kalman filter processing by the integration Kalman filter on the position estimates of the INS and the current vehicle position obtained by the map matching operation thereby correcting errors caused by the vehicle sensors. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A vehicle positioning apparatus for a navigation system established on a smartphone with use of vehicle sensors, comprising:
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an inertial navigation system (INS) incorporating vehicle sensors; a map and navigation system implemented on a smartphone; and a controller for controlling an overall operation of the vehicle positioning apparatus, wherein the INS and the map and navigation system are integrated with one another by an integration Kalman filter, wherein the INS is configured to produce vehicle'"'"'s position estimates based on the acceleration and angular rate measurements from the vehicle sensors, wherein the map and navigation system is configured to receive GPS satellite signals and to produce position estimates indicating an absolute position of the vehicle, and wherein the controller is configured to detect whether the estimated vehicle position has reached an entry point of a tunnel or has reached a point before the entry point of the tunnel by a predetermined threshold distance, to immediately start a map matching operation for matching a current vehicle position with a road link of the tunnel derived from a map database when the estimated vehicle position has reached said either one of points, and to perform a Kalman filter processing by the integration of Kalman filter on the position estimates of the INS and the current vehicle position obtained by the map matching operation thereby correcting errors caused by the vehicle sensors. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification