Design and implementation of a convex-optimized positioning system on wireless RF/FPGA platform

This paper presents the design and implementation of a positioning system based on particle filters and a convex optimization processor. The positioning system uses a virtual base-station transform (VBST) and convex optimization algorithm to deal with the none-light-of-sight (NLOS) problem in wireless communication systems. This study designs a modified resampling particle filter to reduce the processing latency with little performance loss. The proposed system uses four modified particle filters to adopt RSS signals from at most four base stations to estimate their distances to the mobile station. Then, the estimated distances are delivered to a convex optimization processor with the VBST algorithm to locate the mobile station. This work implemented the positioning algorithm on Xilinx Virtex-4 FPGA and RF modules to verify the positioning performance. The measurement and analysis results show that the proposed convex-optimized positioning system reduces 20% RMSE in the mixed NLOS/LOS environment compared to the sole particle filtering approach.