| 摘要 |
871,641. Radar. GENERAL MOTORS CORPORATION. Oct. 8, 1959 [Oct. 29, 1958], No. 34120/59. Class 40(7) Means for indicating to the driver of a first vehicle when it is safe to pull out into the path of an approaching vehicle in order to overtake slower vehicles ahead comprises means on the first vehicle for computing the time to collision with the approaching vehicle and the time to pass the vehicles ahead, a visual indication being given when the time to pass is less than the time to collision by a predetermined margin. As shown the narrow beam of a radar 16 on the first vehicle 12 is directed at the approaching vehicle 14 and the reflected signal is mixed with the transmitted signal to give a beat frequency signal whose frequency is proportional to the closing rate of the two vehicles and whose amplitude rate of increase as determined by a circuit 26 is a function of the distance between the two vehicles, the time to collision being derived therefrom in a computer 30. In order to eliminate signals due to stationary objects and vehicles travelling in the same direction the beat frequency signal is passed through a high-pass filter 22 whose cut-off frequency is controlled by the speedometer 24. The time to pass the vehicle ahead is evaluated in a computer 38 as a function of the number of vehicles ahead as set in by a manual control 42 and the available acceleration at the present speed which is evaluated in a computer 34 controlled by the speedometer 24. When the time to pass is less than the time to collision by a predetermined margin as determined by a comparator 44 a red light 46 is extinguished and a yellow light 48 is switched on. |
