在非地面网络中,依托低轨通信卫星的星地链路、卫星载荷以及地面终端等资源,实现定位解算,是实现未来6G通感一体化的重要技术手段之一.在手机直连卫星等场景下,终端设计上往往只与一颗卫星进行通信,探索单星定位方法具有十分迫切的意义.针对以往单星连续观测定位精度因子差、时钟同步困难、收敛速度慢等难题,提出了一种低轨星座场景下的双向测量差分定位方法,并基于卫星位置精度因子设计了位置更新策略.利用星地链路,采用单程双向测距方法消除时钟误差,通过时间累计测量、终端随机切换的方式弥补单星观测的空间缺陷,优化了终端定位性能.在仿真场景下,基于SpaceX的卫星轨道参数,对所提方案进行了验证,结果表明,采用随机切换卫星的方法进行测量,相比于未切换保持单星测量的终端,定位性能提升近100％;联合解算多个时刻观测数据,能够提升精度收敛速度,减小定位误差,在180 s的仿真时间内利用512次观测数据,当终端切换次数为19次时,最优定位精度可达299.5 m.
Bidirectional measurement differential positioning method for LEO communication satellites
In non-terrestrial network,leveraging resources such as satellite-to-earth links,satellite payloads,and ground terminals of low earth orbit (LEO) communication satellites to achieve positioning calculations is one of the important technical means for realizing the integration of sensing and communication in future 6G network. In sce-narios such as direct-to-handset satellite,terminal designs were often configured to communicate with only one satel-lite,making the exploration of single-satellite positioning methods of urgent significance. Addressing the challenges of poor positioning accuracy,difficulty in clock synchronization,and slow convergence speed associated with previ-ous single-satellite continuous observation,a bidirectional measurement differential positioning method was proposed in the context of low-orbit constellations. Additionally,a position updating strategy based on the satellite position ac-curacy factor was designed. Utilizing the satellite-to-earth link,the method employed a one-way bidirectional ranging technique to eliminate clock errors and compensated for the spatial deficiency of single-satellite observation through cumulative time measurement and random terminal switching,thereby optimizing terminal positioning performance. The results show that measurement through random satellite switching,compared to terminals that maintain single-satellite measurement without switching,enhances positioning performance by nearly 100％. By jointly solving mul-tiple observation data over time,the accuracy convergence speed can be increased,and positioning error can be re-duced. Within a simulation time of 180 s,using 512 observation data,with a terminal switching frequency of 19 times,the optimal positioning accuracy can reach 299.5 m.
low earth orbit communication satellitebidirectional measurementsingle-satellite positioningrandom switching
万方数据
维普
