Abstract: A spark plug having a metallic shell covered with a nickel plating layer and having a groove portion formed between a tool engagement portion and a gas seal portion and having an orthogonal-to-axis sectional area of 36 mm2 or less.

Abstract: A spark plug having a metallic shell covered with a nickel plating layer and having a groove portion formed between a tool engagement portion and a gas seal portion and having an orthogonal-to-axis sectional area of 36 mm2 or less.

Abstract: A method of calculating a present position of a movable body for use in a navigation system, is provided with the processes of: measuring an electric-wave-based measurement position which is a position of the movable body measured on the basis of electric waves for positional measurement, which are transmitted from satellites accompanied by time data indicating an electric-wave-based measurement time which is a time when measuring the electric-wave-based measurement position, at the electric-wave-based measurement time; measuring a self-sustained measurement position which is a position of the movable body measured on the basis of data from self-sustained type sensors built in the movable body; calculating a time difference between the electric-wave-based measurement time and a time when measuring the self-sustained measurement position; correcting the electric-wave-based measurement position on the basis of the calculated time difference; and calculating the present position of the movable body on the basis

Abstract: A navigation system includes: GPS receiving device for receiving satellite information including accuracy information supplied from a plurality of GPS satellites and outputting at least the accuracy information, a measuring position as a receiving point calculated from the satellite information, and a declining rate of measuring accuracy calculated on the basis of the position of the GPS satellites; deviation calculating device for calculating a GPS measuring deviation by using the accuracy information and the declining rate of the measuring accuracy; map information storing device for storing map information including digitalized road information; and current position estimating device for estimating a current position by searching the road information within the radius of the GPS measuring deviation around the measured position.

Abstract: A navigation apparatus is provided with: a measurement unit for measuring a self-position and outputting self-position data; a memory unit for storing map data which includes crossing data and road data; a map-matching unit, for map-matching the self-position data with respect to the road data; and a displaying unit for displaying the map-matched self-position data and the road data on the map data. The map-matching unit is provided with a first crossing searching unit for searching crossing data corresponding to a first crossing connected to a road, to which the self-position data is presently map-matched, and located within a first predetermined distance from the self-position. The first crossing searching unit outputs first candidacy crossing data. The map-matching unit is also provided with a second crossing searching unit for searching crossing data corresponding to a second crossing located within a second predetermined distance from the first crossing.

Abstract: The present invention relates to an on-board navigation system which continuously informs a driver of the degree of approach of a vehicle to a destination by outputting a sound suited to the driver's actual running feeling.

Abstract: An on-vehicle navigation apparatus displays travel locus marks that permits a user to grasp the driving condition of a vehicle having this apparatus installed therein, while securing good visibility of the background map. The on-vehicle navigation apparatus has a storage means for storing a plurality of pieces of travel locus data in response to a predetermined collecting timing, and another storage means for storing an elapsed time from one predetermined collecting timing to the next predetermined collecting timing. The apparatus reads out the travel locus data and elapsed time .DELTA.ti respectively from those storage means, designates different travel locus marks in accordance with the read-out elapsed time .DELTA.ti, and shows the travel locus marks on a display screen on the basis of read-out travel locus data. A traffic jam index Ji and a specific value may be used in place of the elapsed time .DELTA.ti.

Abstract: An on-vehicle navigation apparatus has enhanced efficiency of the use of a memory for storing the locus data, without losing the details and accuracy of a locus pattern drawn on the basis of collected locus data. The on-vehicle navigation apparatus acquires vehicle location information C and time information T, and stores the vehicle location information C as locus data Si and the associated time information T as collecting time data Ti in response to a collection command. The apparatus then computes a travel distance D from the previous locus data collecting position on the basis of the vehicle location information C and the locus data Si, computes elapsed time .DELTA.T from the previous locus data collecting time on the basis of the time information T and the collecting time data Ti, and generates the collection command when the elapsed time .DELTA.T reaches a predetermined time after a predetermined travel distance D is reached.