Range-finding between Vehicles Using Diffuse Light from LEDs

Abstract

For the purpose of saving labor and improving safety in farm operations conducted with a pair of vehicles, automatic driving systems of the following or preceding vehicle have been studied. These systems require real-time and precise measurement of the relative position of vehicles. The authors propose a relative position detection system using diffuse light from LEDs. In the first stage of this study, a range-finder was developed and tested, consisting of two stations which emit high-frequency modulated light at each other. The range between the stations is obtained from the phase difference between the two low-frequency beat signals generated in both stations. Performance tests were conducted under direct sunshine, and the maximum and standard errors from the regression values were about 5 and 3cm respectively in the range from 1 to 10m.