A method for reducing the protection levels (PLs) of aerial vehicles by fusing global navigation satellite systems (GNSS) signals with terrestrial signals of opportunity (SOPs) is developed. PL is a navigation integrity parameter that guarantees the probability of position error exceeding a certain value to be bounded by a target integrity risk. For unmanned aerial vehicles (UAVs), it is desirable to achieve as tight PLs as possible. This paper characterizes terrestrial cellular SOPs’ measurement errors from extensive UAV flight campaigns, collected over the past few years in different environments and from different providers, transmitting at different frequencies and bandwidths. Next, the reduction in PLs due to fusing terrestrial SOPs with a traditional GNSS-based navigation system is analyzed. It is demonstrated that incorporating terrestrial SOP measurements is more effective in reducing the PLs over adding GNSS measurements. Experimental results are presented for a UAV traversing a trajectory of 823 m, during which the VPL of the GPS-based and GNSS-based navigation systems were reduced by 56.9% and 58.8%, respectively, upon incorporating SOPs; while the HPL of the GPS-based and GNSS-based navigation systems were reduced by 82.4% and 74.6%, respectively, upon incorporating SOPs.

中文翻译：

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通过融合 GNSS 和地面机会信号来降低飞行器防护等级


开发了一种通过将全球导航卫星系统（GNSS）信号与地面机会信号（SOP）融合来降低飞行器保护级别（PL）的方法。 PL是导航完整性参数，保证位置误差超过一定值的概率受到目标完整性风险的限制。对于无人机 (UAV)，希望实现尽可能严格的 PL。本文描述了地面蜂窝 SOP 的测量误差，这些误差来自广泛的无人机飞行活动，这些误差是过去几年在不同环境下、从不同提供商处收集的、以不同频率和带宽传输的数据。接下来，分析了由于将地面 SOP 与传统的基于 GNSS 的导航系统融合而导致的 PL 减少。事实证明，与添加 GNSS 测量相比，合并地面 SOP 测量在降低 PL 方面更有效。给出了无人机飞行 823 m 轨迹的实验结果，在此期间，基于 GPS 和基于 GNSS 的导航系统的 VPL 在加入 SOP 后分别降低了 56.9% 和 58.8%；而基于 GPS 和 GNSS 的导航系统的 HPL 在纳入 SOP 后分别降低了 82.4% 和 74.6%。