Matsushita Electric Industrial Co., Ltd.

Honda Giken Kogyo Kabushiki Kaisha

Akihito Shibata

Hiroaki Tsuji

Yoichiro Suga

Hidetoshi Sakurai

A vehicle navigation system automatically corrects the coefficient of its velocity sensor with high precision. This system obtains a distance between two positions measured by a GPS and a linear travel distance calculated on the basis of the signals outputted by the velocity sensor during a period between the measurement of the two positions. Then, the system corrects the velocity sensor coefficient so that the linear travel distance becomes equal to the distance between the two positions.

Vehicle navigation system using GPS including correction of coefficients

The navigation system includes sensors for detecting a condition of a vehicle's movement, an imaginary location calculating device for calculating an existence location of the vehicle, a straight condition processing device for judging whether or not the vehicle is traveling straight, thereby forming a straight travel locus in a condition of straight travel, map data, a road searching-straightening processing device for extracting information concerning a road so as to form a locus as a straight road, a direction rectifying data calculating device for producing a direction offset by calculating direction errors, a location rectifying data calculating device for calculating a location offset, and a location direction rectifying device for rectifying a location and direction of the vehicle by respectively providing a direction offset and location offset with respect to an estimated direction and an estimated location.

Navigation system mounted on vehicle

High degree of accuracy of the position of a vehicle can be ensured by maintaining the continuity of the running path of the vehicle and by correcting the vehicle position to a vehicle position measured by a GPS navigation system when a positional deviation occurs due to sensor errors. Specifically, the vehicle positions are estimated in accordance with signals from sensors for detecting behaviors of the vehicle, and then the vehicle position is shifted onto a designated road having a feature coincident with that of the running path of the vehicle based upon data of the estimated vehicle positions. Further, the vehicle position is corrected to a position measured by use of a GPS receiver only when the cumulative value of distances of the positional shifts made by a number of cycles in past or in a predetermined running distance range exceeds a predetermined threshold value.

On-vehicle position computing apparatus

An object of the present invention is to provide precise calculation of a position and an orientation of a vehicle running or moving on route. Regarding the vehicle moving along a given route and with possible variations in the running orientation it is judged that the vehicle has moved substantially on a straight line when an integrated value of the orientation variations is smaller than a predetermined value. By obtaining a regression line of GPS receiving positions in the straight line, a precise orientation of the vehicle is obtained by adding a difference between the orientations of the straight line and the regression line to an original orientation of the vehicle.

Vehicle orientation calculating device

An engine controller includes a first calculation unit for calculating an amount of fuel injection and ignition timing by a first interrupt process in response to a TDC signal and calculating fuel injection start timing and ignition timing by a higher-order interrupt process having a higher priority than the first interrupt process, a second calculation unit for obtaining a value representing a proportion of the interrupt execution time contained in one interrupt period in accordance with the period of the first interrupt process and the interrupt execution time and comparing the value of the proporiton with a predetermined value, and an inhibition unit for omitting or inhibiting the execution of a next interrupt process by the first calculation means when the interrupt execution time contained in one interrupt period exceeds a predetermined value.

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Yokohama, Japan

Akihito Shibata