| 摘要 |
PROBLEM TO BE SOLVED: To forecast freeze appropriately in accordance with the situation in respective places by a simple structure. SOLUTION: Turning points or freeze accelerating factors existing in a definite area relative to an own vehicle position are extracted from map data (S10, 20), and open-air temperature is detected as a basic factor of freezing (S40). The degree of freezing is forecast by using the contributing level g(t) to freezing of the open-air temperature (t) and the contributing levels C1, C2, etc., to freezing of the respective turning points (S50). Forecast of freeze is performed not by being based on the amount of solar radiation or by previously recording the occurrence of freezing together with its date in respective areas as in the customary official reports but by being based on the open-air temperature as the basic factor and on the specific freeze accelerating factors. Because the freeze accelerating factors can be extracted from map data, typical map data used in navigation processing can be used as it is. |
