Matsushita Electric Industrial Co., Ltd.

Hiroaki Tsuji

Akihito Shibata

Yoichiro Suga

A navigation system includes a GPS receiver. Detection is made as to a number of GPS radio signals received by the GPS receiver. A display is operative for indicating a picture. At least one of a color tone and a luminance of the picture indicated by the display is controlled in response to the detected GPS radio signal number. Calculation may be made as to a rate of a decrease in the GPS radio signal number. In this case, at least one of the color tone and the luminance of the picture indicated by the display is controlled in response to the calculated decrease rate.

Car navigation system

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

An vehicle position and azimuth computing apparatus is constructed to correct both positional errors and azimuth errors caused by the accumulation of a sensor error and a map error and to provide both high positional precision and high azimuth precision. To this end, the vehicle position and azimuth computing apparatus operates to detect both an angular velocity and a moving distance of a vehicle, to compute an on-vehicle position and on-vehicle azimuth, and to detect a straight running condition of the vehicle. Then, after the GPS measurement positions during the straight running of the vehicle have been obtained, regression lines are obtained by regressing the longitudes and latitudes of the measurement positions during the straight running of the vehicle to the moving distance from the straight running starting position of the vehicle. Both a vehicle position and a vehicle azimuth are computed based on the regression lines during the straight running of the vehicle, and then an on-vehicle position and an on-vehicle azimuth, which have been computed based on the detected values of the angular velocity and the moving distance of the vehicle, are modified by using the vehicle position and azimuth obtained based on the GPS measurement data.

Vehicle position and azimuth computing system

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.

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Yokohama, Japan

Hiroaki Tsuji