This paper presents the feasibility study of deploying quantum key distribution (QKD) from high altitude platforms (HAPs), as a way of securing future communications applications and services. The paper provides a thorough review of the state of the art HAP technologies and summarises the benefits that HAPs can bring to the QKD services. A detailed link budget analysis is presented in the paper to evaluate the feasibility of delivering QKD from stratospheric HAPs flying at 20 km altitude. The results show a generous link budget under most operating conditions which brings the possibility of using diverged beams, thereby simplifying the pointing, acquisition and tracking of the optical system on the HAPs and ground, potentially widening the range of future use cases where QKD could be a viable solution.

本文介绍了从高空平台 (HAP) 部署量子密钥分发 (QKD) 的可行性研究，作为保护未来通信应用和服务的一种方式。本文全面回顾了最先进的 HAP 技术，并总结了 HAP 可为 QKD 服务带来的好处。论文中提出了详细的链路预算分析，以评估从在 20 公里高度飞行的平流层 HAP 传送 QKD 的可行性。结果表明，在大多数操作条件下，链路预算充足，这带来了使用发散光束的可能性，从而简化了 HAP 和地面上光学系统的指向、采集和跟踪，有可能扩大 QKD 的未来用例范围一个可行的解决方案。