Target Position Estimation Based On The Comprehensive Observation Module

The actual positioning of the multipath propagation scenario occurs frequently, so there are not only LOS paths, but also NLOS paths. Therefore, positioning research under NLOS environment is very important.Since a single target location estimation model has limitations, such as TOA needs at least three reference nodes, DOA needs at least two reference nodes in line of sight, and the complex multipath environment, it is difficult to localize the target with only a measurement module in NLOS channel situation, so the comprehensive observation model is proposed.The paper presents a target location method, which is based on TOA and DOA fusion observation model with the integration of reflectors’ location information. The method can be used in the Line of sight (LOS) and the Non Line of Sight (NLOS) mixed case. But it is more suitable for there is only one or no LOS node situation. According to NLOS identification techniques, we can identify NLOS reflectors, which can be identified and used to localize themselves via DOA fusion technology. With DOA information ranges which is computed by the base nodes and the reflector nodes, and the TOA measurements between the target node and base nodes, positioning of the target node can be localized. Taylor series of the algorithm can be used to locate the target node.The cumulative probability density of the module has been simulated which is aimed at analyzing the performance of a location estimate. The simulation satisfies E911positioning requirements. Under limited conditions, the number of reference nodes and the number of shared reflection points have been respectively analyzed with the impacts of the positioning performance. It is found that the number of shared reflection nodes has a great impact to the positioning performance, the more shared reflection nodes, the CDF is more bigger in small error area. When the number of the reference nodes is not less than1, positioning performance is better. This paper also studied the relationship between PDOP and AOC, which is a guidance on the positioning system about the reference nodes’locations.