A UWB active sensor localization method based on time-difference back-projection

Time of arrival (TOA) based techniques are widely used in many ranging and localization problems. But because their performance highly depends on the accuracy of the TOA estimation of direct-paths, it's challenging to achieve accurate position estimations under dense multipath or Non-Line-of-Sight (NLOS) condition. In this paper, an algorithm which combines Time difference of arrival (TDOA) technique and back-projection technique is proposed. Based on a coarse estimate of the direct-path, a certain data segment containing direct-path is extracted from each channel. Then a back-projection operation is applied on the extracted data segments so as to strengthen the information of direct-path. A final position estimate is obtained at the same time.