Integrated Framework for Detection and Mitigation of GPS Spoofing Attacks in Smart Grids

全球定位系统是美国最关键的基础设施之一，它为一系列系统和应用程序提供精确的时间和位置。例如，空中、海上和陆地交通、电信、金融交易、实时工业控制系统，以及最重要的电网。具体地说，未来电网的可靠运行取决于全球定位系统的时间同步技术所提供的具有精确定时的电网测量的可用性。尽管该系统非常可靠，但它很容易受到恶意欺骗网络攻击，这些攻击会扰乱测量的时间同步。因此，这误导了依赖它的基础设施的无缝运行。例如，这些攻击对电网造成影响，包括具有严重社会经济影响的停电。该项目的主题是实时检测和缓解对全球定位系统的此类攻击，并将其应用于电网。欺骗攻击表现在不同的物理层上，包括全球定位系统接收器收集的信号、接收器计算的时间和位置，以及最终从电网相量测量单元收集的电压和电流相量测量。提出了一种新颖、严谨、全面的全球定位系统接收器欺骗效应模型以及对电网运行的欺骗效应模型。利用新的模型，这项研究还提供了先进的方法来检测攻击，并最终保护电网免受其有害影响。具体地说，使用基于稀疏性的优化公式来开发在线欺骗检测方案。这些方案能够检测和隔离接收到的卫星信号中的非自然变化以及相关的时间和位置解决方案。基于一种新的测量模型，该模型将欺骗攻击与电网状态直接联系起来，开发了动态算法来维持准确的电网状态估计，同时在存在攻击的情况下无缝地恢复电网的稳定性。

The Global Positioning System is one of the nation's most critical infrastructures, which provides precise timing and location to a host of systems and applications. Examples include air, sea, and land transportation, telecommunications, financial transactions, real-time industrial control systems, and most importantly, the electrical power grid. Specifically, reliable operation of the future electrical power grids depends on the availability of grid measurements with precise timing that is enabled by the Global Positioning System's time-synchronization technology. Although this system is very reliable, it is vulnerable to malicious spoofing cyber-attacks that disrupt the time synchronization of measurements. This consequently misleads the seamless operation of the infrastructures relying on it. For example, these attacks have ramifications on the electrical power grid, including power outages with dire socio-economic implications. The theme of this project is the real-time detection and mitigation of such attacks on the Global Positioning System with applications in power grids. Spoofing attacks manifest themselves at different physical layers including the signals aggregated by the Global Positioning System receiver, the time and location computed by the receiver, and eventually the voltage and current phasor measurements collected from Phasor Measurement Units in the electrical grid. Novel, rigorous, and comprehensive models of the spoofing effects on the Global Positioning System receiver as well as the power grid operation are put forth. Leveraging the novel models, this research additionally furnishes advanced methods to detect the attacks and ultimately protect the grid from their harmful effects. Specifically, online spoofing detection schemes are developed using sparsity-based optimization formulations. These schemes are able to detect and isolate unnatural changes in the received satellite signals and the associated time and location solutions. Based on a novel measurement model that directly relates the spoofing attack with the electrical network state, dynamic algorithms are developed to maintain an accurate state estimate of the power grid, while seamlessly restoring grid stability in the presence of attacks.