Abstract: An apparatus for displaying a travel path of a running body which apparatus includes sensors and a central processing unit (a) for calculating a distance of approach of the running body relative to a target to produce data concerning the approach, (b) for comparing the old and new data and thus successively, renewing the data concerning the approach, thereby obtaining a closest distance of the running body relative to the target, and (c) for deciding that the running body has passed the target when said closest distance is within a predetermined range.

Abstract: An apparatus for displaying a travel path of a running body in which a direction detector includes a geomagnetism sensor as well as a rate-type sensor, such as a gyroscope or gas rate sensor (which includes a flow sensor for detecting a degree of displacement of a gas flow produced by an angular velocity applied thereto) for detecting an angular volocity of change of yawing direction of the moving body, in which a difference in angle between directions detected by the rate-type sensor and the geomagnetism sensor is found and temporarily stored when a power source is temporarily turned OFF during operation of the running path displaying apparatus, and then a declination of the direction detected by the geomagnetism sensor is corrected, depending upon the stored difference in angle, when the power source is turned ON again.