Research Of Target Location And Tracking Technology In Cellular Network

With the further development of cellular wireless communication technology, especially thefurther improvement of communication infrastructure and enhancement of mobile terminals, thelocation-based data service has been booming worldwide, and is becoming the leading one of thevalue added service of operators. Therefore it is of theoretical significance and practical value tothoroughly research the location technology based on cellular network.On the basis of classic location algorithm of cellular network, the paper conducts a studyaiming at the difficult points of location technology which include the measurability ofparameter, the low quality of parameter and the time-varying problem of location channel. Themain points are as follow:1. The paper, taking the practical application of the cellular location technology as a startingpoint, analyzes the research status of the cellular location technology and the main technicalproblems, studies in depth the concept, principle and common methods of the filter typepositioning algorithm, robust estimation technology and robust and adaptive filtering technology,and finally investigates solutions for them in details.2. The problem of measurability of parameter is studied in this part. The existing highaccuracy positioning algorithms are based on time measurement parameters mostly, and areharsh to parameters, which can work on the requirement of the reception of three or more basestations’ signal. Considering the problem of disable location caused by the incapable ofobtaining the required parameters or no measurability of parameter, a new algorithm based onCell-ID is proposed on account of the easy access and extensive application of Cell-ID. Thealgorithm utilizes the serving base station and the adjacent base stations to locate the mobilestation, deals with them in different ways, and adopts the hidden markov model to locate themobile station. The measured results show that the algorithm performs well when the servingbase station is stable and can meets with the requirement of FCC.3. The problem of low quality of parameter is studied in this part. In view of the low qualityof time parameter caused by NLOS propagating, an algorithm based on the improved particleswarm optimization is proposed which is robust to outliers. The advantage of space search ofparticle swarm optimization algorithm is applied to wireless location. The particle population isoptimized by giving consideration to the diversity of particle and the rate of convergence so thatthe population distribution of particle is centralized and diverse. The proposed algorithm cansuppress the effect of NLOS error effectively without the apriori information of channel andstatistical property of the observed value. Simulation results demonstrate that the proposedalgorithm, compared with the traditional method, not only has a higher accuracy, but alsoimproves robustness when NLOS error occurs in different environment.4. the time-varying problem of location channel is studied in this part. The complexwireless environment results in the frequent switch between LOS and NLOS state betweenmobile terminal and base station, the existing algorithm have different degree of position errorby ignoring the switch. An robust and adaptive filtering algorithm based on interacting multiple model is proposed aiming at the problem. Unscented kalman filter and robust unscented kalmanfilter are utilized separately for the reason that the state LOS and NLOS have differentdistribution of TOA observation noise, and the interacting multiple model filter is used toachieve adaptive filtering. Considering the variety of the motion state of mobile station, ARprediction model is used to model the motion equation and updated in real time, so that the biascaused by motion model is effectively suppressed. Simulation results demonstrate that theproposed algorithm performs better under LOS/NLOS condition compared with the traditionalalgorithm.