Civilian Global Navigation Satellite Systems (GNSS) vulnerabilities are a threat to a wide gamut of critical systems. GNSS receivers, as part of the encompassing platform, can leverage external information to detect GNSS attacks. Specifically, cross-checking the time produced by the GNSS receiver against multiple trusted time sources can provide robust and assured PNT. In this work, we explore the combination of secure remote, network-based time providers and local precision oscillators. This multi-layered defense mechanism detects GNSS attacks that induce even small time offsets, including attacks mounted in cold start. Our system does not require any modification to the current structure of the GNSS receiver, it is agnostic to the satellite constellation and the attacker type. This makes time-based data validation of GNSS information compatible with existing receivers and readily deployable.

翻译：民用全球导航卫星系统（GNSS）的脆弱性对各类关键系统构成威胁。作为整体平台组成部分的GNSS接收器，可借助外部信息检测针对GNSS的攻击。具体而言，将GNSS接收器产生的时间与多个可信时间源进行交叉校验，能够提供稳健且可保障的定位、导航与授时（PNT）服务。本研究探索了安全远程网络时间源与本地精密振荡器的组合方案。这种多层次防御机制可检测即使引起微小时间偏移的GNSS攻击，包括冷启动状态下实施的攻击。本系统无需对现有GNSS接收器架构进行任何修改，不依赖卫星星座类型与攻击者类型，使得基于时间戳的GNSS信息验证方法与现有接收器兼容，具备即时部署能力。