[论文解读] Experimental Demonstration of Snapshot Differential Positioning with LEO Satellites

Soham Desai, Dave Cade|arXiv (Cornell University)|Mar 16, 2026

GNSS positioning and interference被引用 0

一句话总结

该论文展示了一种基于快照的微分多普勒定位方法，利用LEO信号（Iridium）在观测不稳定时估计用户位置，在5秒观测 bursts 条件下，误差从约500 m下降到＜265 m，约降低47%。

ABSTRACT

Positioning using Global Navigation Satellite Systems (GNSS) typically requires several seconds of continuous signal reception from satellites in Medium Earth Orbit (MEO). This requirement poses challenges for applications where receivers can only capture signals intermittently or operate under constrained power and visibility conditions. In such scenarios, maintaining continuous tracking or reliable line-of-sight to GNSS satellites may be difficult, and conventional GNSS frequencies may also be vulnerable to interference or jamming. Low Earth Orbit (LEO) satellite constellations provide an attractive alternative due to their lower orbital altitudes, which result in higher received signal strengths, as well as their operation across a wide range of spectrum including Mobile-Satellite Service (MSS) and terrestrial L and S bands. These characteristics make LEO signals promising for navigation in challenging environments. This work presents a snapshot-based differential positioning framework that leverages signals from LEO satellites. In the proposed approach, a receiver collects signals for short durations (5-10 seconds) before entering a low-power state, enabling positioning with intermittent observations. Doppler measurements from multiple satellites are combined with a differential measurement model using a fixed reference receiver to mitigate common errors such as satellite clock bias and ephemeris uncertainty. Experimental results demonstrate that the proposed differential Doppler framework operates effectively within the constraints of snapshot-based reception. The method achieves a position error reduction of approximately 47% even when only three satellites are simultaneously visible to both the rover and the reference station.

研究动机与目标

• 在GNSS持续不可用且环境复杂、难以连续跟踪的情景下，推动导航应用。
• 提出基于快照的差分多普勒框架，利用LEO信号实现观测 bursts 条件下的定位。
• 评估使用固定参考站进行差分多普勒定位的可行性与精度。
• 评估硬件与信号质量对快照定位性能的影响，并展示实际收益。

提出的方法

• 使用固定监测基站测量来自 rover 的同一颗LEO卫星的多普勒移，.
• 对信号进行预处理，将接收帧映射到公开的NORAD ID，利用TLE预测的空间匹配。
• 通过对插值后的零多普勒时间点处卫星位置求平均，得到零多普勒初始位置估计。
• 形成包含纬度、经度、海拔、钟偏和钟漂移的试验状态向量；从模型 f_D = (1/c) f_B ρε̇ + f_O + ḟ_O t 生成试验多普勒曲线。
• 通过从 rover 测量中减去基站误差来得到差分多普勒校正 f_corr,U，以去除公相位误差（星历和大气延迟）。
• 迭代拟合试验多普勒曲线到已校正的 rover 多普勒测量，以估计 rover 位置。

实验结果

研究问题

• RQ1 在连续跟踪不可行时，来自LEO卫星的快照（5秒）多普勒观测是否能实现准确定位？
• RQ2 在不稳定观测条件下，固定基站的差分校正能在多大程度上提升 rover 位置精度？
• RQ3 TLE 不准确和振荡器漂移对快照差分定位性能有何影响？
• RQ4 在快照中实现有意义的位置改进至少需多少颗互相重叠的卫星？

主要发现

• 在没有差分校正的情况下，独立的 rover 定位误差较大（约500 m）。
• 在固定基站的差分校正下，rover 位置误差降至＜265 m（绝对）且 RMS 多普勒误差降至10–20 Hz。
• 基站多普勒 RMSE 为5–7 Hz，而 rover RMSE为80–100 Hz，原因在于快照获取与振荡器漂移。
• 3颗重叠卫星即可在快照中达到约47%的定位误差降低。
• 实验设置在旧金山湾区进行约55分钟的5秒 bursts 测试，使用两台 SDR 基站。
• 差分多普勒定位在资源受限的LEO导航环境中表现出可行性，若增加卫星数量与传感融合，性能有望进一步提升。