With the support of inter-satellite link technology, GNSS can theoretically achieve the distributed autonomous orbit determination (AOD) function. Traditional AOD operation generally utilizes the forecast ephemeris uploaded by operational control segment (OCS) as the filter reference orbits or to constrain the orbit systematic errors, especially for constellation overall rotation effects in Earth-centered inertial (ECI) coordinate system. To get rid of the dependency on forecast trajectories for saving the OCS workload and also reduce the onboard storage and computation burden, we use a sequential extended Kalman filter to estimate the orbit parameters and consider main perturbation forces acting on satellites in the AOD solution. In particular, for modeling solar radiation pressure (SRP), an empirical prediction function derived by historical SRP estimates is introduced. Using the proposed scheme, the orbit 3D accuracy and user range error (URE) of the first 180-day distributed AOD solution for BeiDou-3 MEOs with precise Earth rotation parameters (ERPs) can reach about 2.10 and 0.43 m, respectively. The constellation rotation errors implied in AOD orbits around the X-, Y- and Z-axis of ECI system are less than 15.0, 11.7 and 15.2 mas, respectively. For real-world AOD scenarios, precise ERP is not available for satellites. With the 180-day prediction ERP, the orbit 3D errors and URE due to the gradually increased UT1-UTC error can be elevated to 14.62 and 2.91 m during our AOD experiments. Result analysis shows if OCS can upload latest prediction ERP at a frequency of once a week, the 180-day distributed AOD is expected to consistently produce real-time orbits preferable to broadcast ephemeris derived by the traditional region L-band tracking network.

在星间链路技术的支持下，GNSS理论上可以实现分布式自主定轨（AOD）功能。传统的AOD运行一般利用运行控制部分（OCS）上传的预报星历作为过滤参考轨道或约束轨道系统误差，特别是对于地心惯性（ECI）坐标系下的星座整体旋转效应。为了摆脱对预测轨迹的依赖以节省 OCS 工作量并减少星上存储和计算负担，我们使用顺序扩展卡尔曼滤波器来估计轨道参数并在 AOD 解决方案中考虑作用于卫星的主要扰动力。特别是，为了模拟太阳辐射压力 (SRP)，引入了由历史 SRP 估计得出的经验预测函数。采用该方案，具有精确地球自转参数（ERP）的北斗三号MEO首个180天分布式AOD解决方案的轨道3D精度和用户距离误差（URE）分别可达约2.10和0.43 m。 AOD 轨道绕 ECI 系统 X、Y 和 Z 轴隐含的星座旋转误差分别小于 15.0、11.7 和 15.2 mas。对于现实世界的 AOD 场景，精确的 ERP 不适用于卫星。通过 180 天的预测 ERP，在我们的 AOD 实验中，由于 UT1-UTC 误差逐渐增大，轨道 3D 误差和 URE 可提高到 14.62 和 2.91 m。结果分析表明，如果OCS能够以每周一次的频率上传最新的预测ERP，那么180天的分布式AOD预计将持续产生优于传统区域L波段跟踪网络广播星历的实时轨道。