Temperature compensation method using base-station for spread spectrum sound-based positioning system in green house

To apply Spread Spectrum (SS) sound-based positioning system in green house, measurement accuracy was investigated by using Base- Station (BS) for compensating temperature. In this experiment, normalized correlation value and correlation ratio were used to detect correlation peak of direct wave of SS sound. When 9 positions in actual greenhouse were measured, success rate to detect direct wave of SS sound was 99%. As the result, this correlation peak detection method is useful to detect correlation peak of direct wave. Average measurement error at each position was 55 mm and improved about 20 mm by using BS method. Moreover, when center correlation peak was detected, average measurement error was 15.5 mm. Thus, BS method enables SS sound-based positioning system to be useful in green house.