Design And Implementation Of TOA Ranging System Based On Software Defined Radio

With the rapid development of wireless communication technology and intelligent mobile terminals,wireless positioning technology has broad application prospects in the fields of public safety,transportation and logistics.The wireless ranging system is a prerequisite for accurate wireless positioning.However,existing wireless ranging systems often use dedicated hardware platforms.The dedicated ranging hardware platform has a single function,which is not conducive to secondary development and integration of new functions.Software Defined Radio(SDR)platform has the characteristics of low cost,flexible algorithm,and easy program upgrade and replacement.For wireless systems with different requirements,Software Defined Radio can implement various functions in software programming on a common hardware platform.This paper designs and develops a wireless ranging platform based on SDR.Using SDR equipment to achieve wireless ranging function through software development.On this basis,further explore the application potential of SDR equipment,and achieve the integration of wireless ranging and channel measurement and the integration of wireless ranging and data transmission.At the transmitting end,periodic narrow pulse signals of equal amplitude and phase are transmitted.The receiving end estimates the time of arrival of the wireless signal by extracting the phase information of the received signal and using the extracted signal phase and the principle of signal distortion-free transmission,and then estimates the distance between the transmitting and receiving antennas to achieve wireless ranging.On this basis,a lot of actual measurement is carried out in typical outdoor scenes using the wireless ranging platform.On the one hand,the correctness of hardware and software of the platform is verified,on the other hand,the statistical characteristics of ranging error of the platform are given,and the influence of different measurement parameters on ranging error is analyzed.The measurement results show that the ranging error decreases with the increase of bandwidth.The linear fitting method is used to establish the corresponding model of ranging error and bandwidth based on the actual measurement results,which provide the basis for the performance evaluation of the wireless ranging system.In addition,through the analysis of the measurement results of different scenes,it can be concluded that although the principle of signal distortion-free transmission is relatively simple,this method requires higher radio wave propagation environment.The multipath component in the measurement scene has a great impact on the measurement results,and the influence of multipath component increases with the increase of distance.Finally,in order to explore the application potential of the SDR-based wireless ranging system in the wireless positioning system,this paper further develops the performance evaluation of the positioning error simulation based on the measured ranging error model of the SDR-based ranging system.This paper establishes a quantitative relationship between the SDR system bandwidth,the number of SDR ranging nodes,the deployment scheme of SDR ranging nodes and the positioning errors through numerical simulation.The theoretical simulation results show that the positioning accuracy can be improved to a certain extent by properly increasing the number of SDR ranging nodes,increasing the measurement bandwidth of SDR ranging nodes,and evenly placing SDR ranging nodes around target nodes.The theoretical simulation results have certain reference and guiding significance for the design and implementation of SDR-based positioning system.