Protected satellite communications (SatComs) exhibit specific characteristics such as security, intelligence, anti-jamming, and nuclear disaster survivability. They constitute one of the key research topics in modern military communications and have become the basic means for implementing strategic and tactical command and control. Currently, the United States military is using the latest advanced extremely high-frequency (AEHF) system to provide protected communications. Other countries are also employing their own protected SatCom systems to meet future operational requirements. Furthermore, in the modern intelligent age, many intelligent-related technologies are introduced into the protected SatCom systems to provide more secure and efficient communication services. In this paper, a comprehensive overview of the protected SatCom systems is presented. More specifically, a system overview of the protected SatComs is illustrated. Our focus is placed on the critical technologies and practical applications, and finally discuss remaining challenges and look forward to the future research directions. It is undoubted that the protected SatCom is one of the most important systems in military communications, both now and in the future.

受保护的卫星通信（SatComs）具有特定的特征，例如安全性，情报，抗干扰和核灾难的生存能力。它们构成了现代军事通信中的关键研究主题之一，并已成为实施战略和战术指挥与控制的基本手段。当前，美国军方正在使用最新的先进超高频（AEHF）系统来提供受保护的通信。其他国家也正在使用他们自己的受保护的SatCom系统，以满足未来的运行要求。此外，在现代智能时代，受保护的SatCom系统中引入了许多与智能有关的技术，以提供更安全，更高效的通信服务。在本文中，介绍了受保护的SatCom系统的全面概述。更具体地说，说明了受保护的SatComs的系统概述。我们的重点放在关键技术和实际应用上，最后讨论剩余的挑战并期待未来的研究方向。毫无疑问，无论现在还是将来，受保护的卫星通信系统都是军事通信中最重要的系统之一。