The vehicle industry has applied active suspension system for a long time to enhance ride-quality and driving stability. However, only a small improvement is seen in the absence of a preview sensor, and thus it is an integral component in designing active suspension systems. Devices such as stereo vision, lidar, and radar systems thus far have been used when building preview information for active suspension systems. These devices have some drawbacks, however, including costliness and the requirement of complex computations. A high performance data processing device is thus needed to compute complicated calculations in real time, which further increases costs. The goal of this research is to examine the use of a low cost ultrasonic sensor to compute road surface height estimation in real time by using simple algorithms.