考虑雨衰 阴影 和多径影响，关于超声波倒车雷达测距的，用蒙特卡洛模拟的方法计算美式期权的价格以及基本描述。- Consider shadow rain attenuation and multipath effects About ultrasonic parking radar ranging, Monte Carlo simulation method of calculating the American option price and basic descr iption.