Forward Looking 2- dimensional Laser Radar for ACC-Systems
In the adaptive cruise control system, the scanning laser radar is widely used to detect the preceding car even on the winding road. The conventional scanning laser radar scans only horizontally , utilizing a fan beam which is horizontally narrow and vertically wide. Since the conventional system scans only horizontally, it has the following drawback: To detect the preceding car even on the highway with up/down hill, it is necessary to utilize a vertically wide fan beam. Therefore, while the car is traveling on a flat road, the scanning laser radar may detect the objects above the road, such as traffic signs, guideboards and bridges etc., in stead of the preceding cars.
To overcome this drawback, we have developed 2-dimensional laser beam scanner with a rotating polygon mirror. Using this laser beam scanner, we have realized the new 2-dimensional scanning laser radar system characterized in that it has six lines raster scan by vertically and horizontally narrow beam.
By this system, it is made possible to differentiate the preceding cars from the objects above the road as well as to detect the preceding car even on the highway with up/down hill.