TRAVEL DISTANCE MEASURING INSTRUMENT

摘要

PROBLEM TO BE SOLVED: To provide a travel distance measuring instrument which can obtain the accurate travel speed and comulative travel distance of an automobile through a simple externally fitting process. SOLUTION: A travel distance measuring instrument is provided with an alternator noise detecting means 1 which finds the number of revolutions of the engine of an automobile from the frequency of the alternator noise of the automobile, a car speed sensing means 3 which finds the travel speed of the automobile from a GPS receiving means 4, a converted value calculating means 2 which finds the relation between the number of revolutions of the engine and the speed of the automobile as a converted value, and a distance calculating means 5 which finds the cumulative travel distance of the automobile from the travel speed. The car speed measuring means 3 finds the travel speed by using the number of revolutions of the engine and a stored converted value when the GPS receiving means 4 is not usable.