Fig. 1. Positioning structure

Fig. 2. PD layout

Fig. 3. Schematic diagram of subregional positioning model

Fig. 4. Structure diagram of ELM neural network

Fig. 5. Flow chart of BES-ELM positioning algorithm

Fig. 6. Schematic diagram of Elman model

Fig. 7. Schematic diagram of WDME positioning model

Fig. 8. Results of regional division

Fig. 9. Comparison of positioning errors

Fig. 10. Distribution diagram of positioning effects

Fig. 11. Distribution diagram of accumulative errors

Fig. 12. Distribution diagram of positioning errors

Fig. 13. Distribution diagram of accumulative errors

Fig. 14. Distribution curves of accumulative errors

Fig. 15. Distribution diagram of boundary area positioning errors

Fig. 16. Histogram of positioning errors proportion