A Database Method to Mitigate the NLOS Error in Mobile Phone Positioning

Abstract

Non line of sight (NLOS) error is well known to be a major source of error in mobile phone positioning. It is simply caused by the dense buildings blocking the line of sight (LOS) propagation of RF signal. Hence mobile station (MS) appears further away from the base transceiver station (BTS) than it actually is. To mitigate the effect of NLOS error, a basic method is to generate the NLOS error correction map, and then use the correction map to correct the measurements. Therefore, a more accurate MS location can be estimated. How to efficiently generate the correction map is a major problem of this approach. A method based on the spatial correlation is proposed in this paper. An experiment was carried out in a typical suburban area to verify this idea. The test result shows the proposed method based on universal kriging can improve the accuracy of position estimate using time difference of arrival technique.