LEO-地月DRO编队非瞬时星间测距自主定轨分析
Analysis of Autonomous Orbit Determination for LEO-Earth-Moon DRO Constellation Using Time-Delayed Inter-satellite Ranging Observation
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摘要: 面向地月空间导航对自主性与高精度的需求, 针对低轨(Low Earth Orbit, LEO)卫星与地月空间远距离逆行轨道(Distant Retrograde Orbit, DRO)卫星组成的异构编队, 介绍了在圆型限制性三体问题下微分修正DRO轨道的理论方法; 在太阳系质心天球坐标系(Barycentric Celestial Reference System, BCRS)下, 建立了双单程星间测距(Dual One-Way Ranging, DOWR)的组合观测模型, 并对光行时延迟与广义相对论效应引起的时钟偏差及其量级进行定量分析. 基于数值仿真, 考察了非瞬时上下行观测条件下不同上下行观测时间间隔对LEO-地月DRO编队自主定轨精度的影响. 仿真结果表明: (1)在地月空间环境中, 广义相对论效应导致的DOWR测距误差达5−30 ns量级, 是DOWR中必须修正的误差项; (2)仅利用DOWR观测即可实现编队自主定轨. 其中, LEO卫星三维定位精度优于10 m; DRO卫星优于50 m, 误差主要集中在轨道法向, 部分弧段径向与切向精度可达米级; (3)在上下行观测时间间隔0−20 s范围内, 延长时间间隔虽可提升系统可观测性, 但由于时间间隔较短提升有限, 对整体定轨精度改善不明显, 各方案定轨精度相当. 该结果表明, 在保证观测值精度的前提下, LEO-地月DRO编队的定轨系统可放宽上下行观测时间间隔的要求, 有利于提升系统运行容错能力. 研究验证了LEO-地月DRO异构编队在地月空间实现高精度自主导航的可行性, 为未来地月导航星座体系设计提供理论依据与技术参考.Abstract: To address the demand for autonomy and high precision in cislunar space navigation, this study focuses on a heterogeneous constellation composed of Low Earth Orbit (LEO) satellites and Earth-Moon Distant Retrograde Orbit (DRO) satellites. The theoretical method for differential correction of DRO orbits under the Circular Restricted Three-Body Problem (CR3BP) is introduced. In the Barycentric Celestial Reference System (BCRS), a combined observation model for Dual One-Way Ranging (DOWR) is established, and the clock biases caused by light-time delay and general relativistic effects are quantitatively analyzed. Based on numerical simulations, the impact of different uplink-downlink observation intervals on the autonomous orbit determination accuracy of the LEO-Earth-Moon DRO constellation is investigated under non-instantaneous observation conditions. The simulation results show that: (1) In the cislunar space environment, the ranging error in DOWR caused by general relativistic effects reaches the order of 5−30 ns, which is an error term that must be corrected. (2) Autonomous orbit determination for the LEO-Earth-Moon DRO constellation can be achieved using only DOWR observations. Specifically, the three-dimensional positioning accuracy of LEO satellites is better than 10 m. For DRO satellites, the accuracy is better than 50 m, with errors primarily concentrated in the orbital normal direction, while radial and tangential accuracies can reach the meter level in some arc segments. (3) Within the range of 0−20 seconds for uplink-downlink observation time intervals, extending the interval can improve system observability. However, due to the short duration of the interval, the improvement is limited, and the enhancement of overall autonomous orbit determination accuracy is not significant. The accuracy of different schemes is comparable. These results indicate that, subject to maintaining measurement accuracy, the temporal constraints on uplink-downlink observation intervals for the LEO-Earth-Moon DRO constellation orbit determination system can be relaxed. This relaxation contributes to enhanced system robustness and operational redundancy. This study validates the feasibility of high-precision autonomous navigation for LEO-Earth-Moon DRO heterogeneous constellation in cislunar space, providing a theoretical basis and technical reference for the design of future cislunar navigation constellations.
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