Common vulnerabilities in typical intelligent cyber-physical systems such as unmanned aerial vehicles (UAVs) can be easily exploited by cyber attackers to cause serious accidents and harm. For successful UAV operations, security against cyber attacks is imperative. In this paper, we propose a modified sliding innovation sequences (MSIS) detector, based on the extended Kalman filter optimal state estimation, for a dynamic quadrotor system to detect cyber attacks inflicted on both its actuators and sensors in real time. These cyber attacks include random attacks, false data injection (FDI) attacks and denial-of-service (DoS) attacks. The MSIS detector computes the operator norm of the normalized innovation (residual) sequence within a sliding time window and triggers the alarm if the value is above the preset threshold. For a quadrotor undergoing rapid turns in a complex trajectory, the detector observes a reduced false alarm rate as compared to other state estimation-based detectors. To address the initial estimation error problem, we implement an iteration procedure to initiate and calibrate the detector. By evaluating the sample covariance of the normalized innovation sequence, the MSIS detector has the capability to isolate cyber attacks. Finally, simulation results of a quadrotor in a periodic, complex trajectory flight are provided to verify the effectiveness of the MSIS detection and isolation method.

中文翻译：

---

具有改进的滑动创新序列的四旋翼无人机的网络攻击检测和隔离

典型的智能网络物理系统（如无人驾驶飞行器（UAV））中的常见漏洞很容易被网络攻击者利用，造成严重事故和伤害。对于成功的无人机操作，针对网络攻击的安全性势在必行。在本文中，我们提出了一种改进的滑动创新序列 (MSIS) 检测器，该检测器基于扩展卡尔曼滤波器最优状态估计，用于动态四旋翼系统实时检测对其执行器和传感器造成的网络攻击。这些网络攻击包括随机攻击、虚假数据注入 (FDI) 攻击和拒绝服务 (DoS) 攻击。MSIS 检测器在滑动时间窗口内计算归一化创新（残差）序列的算子范数，并在该值高于预设阈值时触发警报。对于在复杂轨迹中快速转弯的四旋翼飞行器，与其他基于状态估计的检测器相比，检测器的误报率降低。为了解决初始估计误差问题，我们实施了一个迭代程序来启动和校准检测器。通过评估标准化创新序列的样本协方差，MSIS 检测器具有隔离网络攻击的能力。最后，给出了四旋翼在周期性、复杂轨迹飞行中的仿真结果，以验证MSIS检测和隔离方法的有效性。我们实现了一个迭代过程来启动和校准检测器。通过评估标准化创新序列的样本协方差，MSIS 检测器具有隔离网络攻击的能力。最后，给出了四旋翼在周期性、复杂轨迹飞行中的仿真结果，以验证MSIS检测和隔离方法的有效性。我们实现了一个迭代过程来启动和校准检测器。通过评估标准化创新序列的样本协方差，MSIS 检测器具有隔离网络攻击的能力。最后，给出了四旋翼在周期性、复杂轨迹飞行中的仿真结果，以验证MSIS检测和隔离方法的有效性。