Research on Maximum Likelihood Estimation Location Method Based on UWB Platform

UWB platform is a system suiTABLE for high precision ranging and location. A location algorithm suiTABLE for indoor and outdoor scenes is essential to make better use of UWB platform. Maximum likelihood estimation(AML) is a simple and accurate location algorithm, which can meet the requirements of location algorithm based on UWB platform. AML method is studied in this paper. Firstly, we analyze the location principle of AML method. Then, we carried out indoor and outdoor location experiments to verify the effectiveness of AML. Finally, we compare and analyze the mean uncertainty of different location algorithms in different environments, and draw conclusions based on the analysis results. The experimental results show that AML has the highest accuracy in both indoor and outdoor environments, and is the most suiTABLE location algorithm for UWB-based location in the most simple and commonly used LS, AML and trilateral measurement methods. Keywords—UWB Platform,AML,Location,Uncertainty Wireless location could provide crucial position information for various application systems, including PHM (Prognostics and Health Management) system, aerospace, emergency scheduling, rescue and relief, and many other related location-based services system[1]. Location information has certain reference value and decision value, and plays an important role in these systems. However, many uncertainty factors, such as environmental noise, measurement error, non-line-ofsight (NLOS) or multipath propagation of radio signals, have a negative impact on location accuracy, resulting in poor location [1-3]. Even worse, it may cause wrong result or wrong action for later deep processing method or decision-making system, because the later processing method or system utilize the localization result as important priori information. Ultra-wideband(UWB) technology is a sub nanosecond ultra narrow pulse wireless communication technology, which directly modulates impulse pulses with steep rise and fall time, so that the signal has GHz bandwidth. Compared with other location technologies, UWB technology has many advantages, such as high time resolution, good anti-multipath effect, high security, strong penetration, simple hardware structure, etc. It is suiTABLE for high-precision ranging and location, and has a wide application prospect[4-8]. At present, the location algorithms based on UWB platform include Fang algorithm[9], Chan algorithm[10], Taylor algorithm[11], least square method (LS), maximum likelihood estimation (AML), trilateral measurement (Caffery) and so on. AML is a location method based on maximum likelihood principle. It is a location algorithm suiTABLE for UWB platform which is based on TOA information and has good location accuracy as well as low computational complexity. This paper will use LS, AML, Caffery, the three most simple and commonly used algorithms in indoor and outdoor scenes, to carry out location experiments under the set scenarios. By comparing and analyzing mean location uncertainty of different algorithms in the coverage area of the location network, it shows the superiority of AML algorithm in UWB platform location. The rest of this paper is organized as follows: In part I, we will introduce UWB (mainly introduce its ranging principle); in part II, we will analyze the principle of AML location; in part III, we will illustrate the advantages of AML algorithm over LS and Caffery location methods through simulation; in part IV, we will verify the accuracy advantages of AML over LS and Caffery location methods through experiments; finally, we come to the conclusion of this paper.