Three dimensional localization with ultrasonic at wireless sensor networks

In this work, 3D localization is produced by utilizing ultrasonic and radio signals at wireless sensor network and for this purpose time difference of arrival is used for localization. Measurement system is designed by using four hardwares (nodes) which have the same properties. One of the nodes is moving, other three nodes perform as references. The frequency used between the nodes is 2.4GHz and ultrasonic signal propagates with 40KHz. All of the nodes benefit from TinyOS operating system. After achieving appropriate number of measurement, calculations are brought about considering necessary variance and standard deviation. As a result, localization is calculated with % 2.5 error.