Comparison of localization methods using CSS-UWB WPAN for mobile robots

Ultra Wideband (UWB) techniques are utilized to localize mobile robots in indoor environment. Although there are many methods, such as IR-UWB, CSS-UWB, and AWGN-UWB, it is hard to make it smaller. CSS-UWB technique is a viable solution, since it has a chip solution. By utilizing chirp signal, ranging counter, and SDS-TWR technique, CSS-UWB acquires under-meter ranging measurements. To solve position with these measurements in severe indoor condition, robust location algorithm should be exploited. Gauss-Newton (GN) method shows good performance compared to other algorithms. However, GN method has a chance to diverge in poor geometry condition. Moreover, different anchor heights could cause divergence problem in three-dimensional condition. The quadratic corrected least square (QCLS) method is introduced to alleviate this divergence problem. Not only classical QCLS method, but also other methods such as modified QCLS (MQCLS) are introduced. The performances of these algorithms are analyzed by both simulation and experimental results. MQCLS algorithm shows better performance for the edge of the geometry.