TOA Based Cooperative Localization For Wireless Sensor Networks

With the rapid development and wide application of wireless communication technology,geographical location information has attracted more and more attention in civil and military fields.The current Global Positioning System(GPS)and Bei Dou Navigation Satellite System(BDS)can effectively provide the geographical location information in outdoor environments.While in some special environments such as indoors,underground and underwater,both the GPS and Bei Dou systems don't work well.Therefore,a new kind of localization methods based on Wireless Sensor Networks(WSN)technology has become a hot research and application field due to their good performance in such special environments.This paper mainly studies the WSN localization algorithms based on Time-of-Arrival(TOA).The main innovations are as follows:(1)A TOA-based WSN cooperative localization algorithm is proposed.Firstly,the optimization problem of the target location is established.Secondly,the original non-convex optimization problem is transformed into a convex form by using the Mixed Semi-definite and Second-order Cone Programming(Mixed SD/SOCP)theory,and a sub-optimal solution can be obtained quickly.Computer simulation results show that the Root Mean Squared Error(RMSE)of the proposed algorithm is lower and closer to the Cramer-Rao lower bound(CRB).(2)For the TOA-based WSN cooperative localization problem,a least squares problem based on maximum likelihood criterion is established.The original non-convex and nonlinear problem is transformed into a mixed semi-definite and second-order cone problem which is convex and easy to solve.The simulation results show that the performance of the proposed method is superior to that of the other compared algorithm in multiple scenarios,and the RMSE is closer to CRB.