Method for alarming inner pressure lowering of tires using GPS information and device thereof, and program for alarming inner pressure lowering of tires
Provided is a method which is free from falling into a state impossible for detecting inner pressure lowering of tires even when GPS signals cannot be received and capable of precisely detecting inner pressure lowering of tires. A method for alarming inner pressure lowering of tires comprising a step of receiving satellite electric wave utilized for GPS and then detecting inner pressure lowering of tires utilizing the information of the satellite electric wave, and a step of detecting inner pressure lowering of tires utilizing wheel speed information, wherein said method comprises a step of judging whether the judgment result of inner pressure lowering of tires detected in the respective steps is adopted or not.
1. A method for alarming inner pressure lowering of tires comprising:
receiving satellite electric wave utilized for GPS;
detecting inner pressure lowering of tires utilizing information of the satellite electric wave; and
detecting inner pressure lowering of tires utilizing wheel speed information;
judging whether the judgment result of inner pressure lowering of tires detected in the detecting steps is adopted or not,
wherein the step of detecting inner pressure lowering of tires utilizing satellite electric wave information comprises judging inner pressure lowering of tires from change in size of dynamic load radii by comparing an effective dynamic load radius with an initial value preliminarily stored as a dynamic load radius at a normal inner pressure, wherein the effective dynamic load radius is obtained by calculating an apparent dynamic load radius of a tire at running by successively comparing a calculated speed of a vehicle by a GPS device, in which the speed of the vehicle at running is calculated from information obtained by the GPS device, with a rotational speed of the tire obtained by a tire rotational speed detection apparatus installed on tire rotational portions of four wheels of the vehicle, and
wherein judging the apparent dynamic load radius to be effective only when a running state is judged to be straight on a flat road at a constant speed from GPS positioning information.
2. The method of claim 1 , wherein the step of detecting inner pressure lowering of tires utilizing wheel speed information comprises a step of detecting rotational information of respective tires, a step of calculating wheel speeds from the rotational information of respective tires, and a step of judging air pressure lowering of tires by comparing the mutual wheel speeds of four wheels.
3. A device for alarming inner pressure lowering of tires comprising:
means for receiving satellite electric wave utilized for GPS;
first means for detecting inner pressure lowering of tires utilizing information of the satellite electric wave; and
second means for detecting inner pressure lowering of tires utilizing wheel speed information,
means for judging whether the judgment result of inner pressure lowering of tires detected by the first and second detecting means is adopted or not,
wherein the first means for detecting inner pressure lowering of tires utilizing satellite electric wave information comprises means for judging inner pressure lowering of tires from change in size of dynamic load radii by comparing an effective dynamic load radius with an initial value preliminarily stored as a dynamic load radius at a normal inner pressure, wherein the effective dynamic load radius is obtained by calculating an apparent dynamic load radius of a tire at running by successively comparing a calculated speed of a vehicle by a GPS device, in which the speed of the vehicle at running is calculated from information obtained by the GPS device, with a rotational speed of the tire obtained by a tire rotational speed detection apparatus installed on tire rotational portions of four wheels of the vehicle, and
wherein judging the apparent dynamic load radius to be effective only when a running state is judged to be straight on a flat road at a constant speed from GPS positioning information.
4. A computer program product for alarming inner pressure lowering of tires, the computer program product being embodied on a non-transitory computer readable medium, the computer program product comprising computer-executable instructions of:
receiving satellite electric wave utilized for GPS;
detecting inner pressure lowering of tires utilizing information of the satellite electric wave;
detecting inner pressure lowering of tires utilizing wheel speed information; and
judging whether the judgment result of inner pressure lowering of tires detected in the detecting steps is adopted or not,
wherein the step of detecting inner pressure lowering of tires utilizing satellite electric wave information comprises judging inner pressure lowering of tires from change in size of dynamic load radii by comparing an effective dynamic load radius with an initial value preliminarily stored as a dynamic load radius at a normal inner pressure, wherein the effective dynamic load radius is obtained by calculating an apparent dynamic load radius of a tire at running by successively comparing a calculated speed of a vehicle by a GPS device, in which the speed of the vehicle at running is calculated from information obtained by the GPS device, with a rotational speed of the tire obtained by a tire rotational speed detection apparatus installed on tire rotational portions of four wheels of the vehicle, and
wherein judging the apparent dynamic load radius to be effective only when a running state is judged to be straight on a flat road at a constant speed from GPS positioning information.