A covert spoofing algorithm of an unmanned aerial vehicle (UAV) based on GPS/INS integrated navigation is analyzed in this paper. The proposed algorithm theoretically proves the fact that: when the acceleration component of the counterfeit GPS signal is the difference between the UAV's current acceleration and the spoofing control input, the UAV can be covert spoofed. To avoid adverse consequences (detection or crash) caused by frequent changes in UAV flight during the GPS spoofing attacks, the proposed algorithm requires that the deception trajectory planned by the GPS spoofer is slowly changing relative to the reference trajectory which is pre-set by the UAV. Simulation results have verified the correctness of the proposed covert spoofing algorithm of UAV. Moreover, the spoofing effect is more distinct when the deception trajectory planning is considered.

To meet the task requirements of using GNSS spoofing signals to achieve directional spoofing of unmanned target platforms, this paper proposes an INS/GNSS integrated navigation covert directional spoofing method, which can be used in key place security defense and public security protection scenarios. Taking the steady-state gain matrix as a breakthrough, this paper firstly studies the influence mechanism of GNSS spoofing signals on the position output of INS/GNSS integrated navigation, and then deduces the feasibility of directional spoofing by using exponential spoofing signal with two adjustable parameters in INS/GNSS integrated navigation mode. Then, the influence of spoofing signals on the attitude and speed of the integrated navigation output is analyzed, and the relevant constraints of velocity and attitude errors are introduced to determine the exponential GNSS spoofing signals model that meets the requirements of covertness, and finally the task of covert directional spoofing of the target unmanned platform is realized. Simulation and experiments verify the effectiveness and correctness of INS/GNSS covert directional spoofing method.

With the expansion of the exploration scope of underwater vehicles and the improvement of their safety requirements, integrated navigation under passive conditions has become a hot topic in the field of navigation. Due to the stability and detectability of the Earth’s gravity field, the use of a matching result for external correction of inertial navigation systems (INSs) can be effective. For practical navigation applications, an inertial gravity matching integrated navigation algorithm must be designed for real-time applicability, diversified output information capability, and anti-interference capability. In this paper, an INS/gravity matching (INS-GM) integrated navigation algorithm is improved to extract the information of gravity fields in real time and correct the navigation results, and a robust integrated algorithm is proposed. Through two-hierarchy filtering, correction of the gravity field to the carrier position and of the integrated navigation system is obtained. According to the first-hierarchy filtering noise characteristics of gravity matching, the robustness of the algorithm to a complex environment is improved by second-hierarchy filtering. The ocean experiment data processing results show that the algorithm can effectively handle a certain degree of initial error, and an integrated navigation accuracy of 205 m is achieved in a good experimental environment. In the case of severe test conditions, the accuracy of the robust integrated navigation algorithm is 72% higher than that of the ordinary navigation algorithm, and it has a strong anti-jamming ability, which can meet the requirements of marine inertial gravity matching integrated navigation tasks.

In order to solve the spoofing problem of SINS/GNSS tightly integrated navigation system with inertial assist spoofing detection module, this paper proposes a covert spoofing algorithm for SINS/GNSS tightly integrated navigation system. Firstly, the influence mechanism of the GNSS spoofing signal on the innovation and state estimation parameters of the SINS/GNSS tightly integrated navigation system is analyzed, and then the GNSS spoofing signal model is established with the constraint condition of the influence of the GNSS spoofing signal on the innovation and state estimation parameters of the SINS/GNSS tightly integrated navigation system. Secondly, the mathematical model of covert spoofing is constructed by using the GNSS spoofing signal model. Finally, SINS/GNSS tightly integrated navigation system is spoofed by GNSS spoofing signal generated according to the mathematical model of covert spoofing. Note to Practitioners —The motivation of this paper is to solve the spoofing problem of SINS/GNSS tightly integrated navigation system, so as to realize the control of the illegal unmanned platform equipped with tightly integrated navigation system. The existing spoofing methods are easily detected by the spoofing detection module, and it is difficult to meet the spoofing requirements of SINS/GNSS tightly integrated navigation system equipped with inertial aided spoofing detection module. This paper proposes a covert spoofing algorithm. Firstly, the influence mechanism of GNSS spoofing signal on SINS/GNSS tightly integrated navigation system is analyzed. Then, the mathematical model of covert spoofing is established by taking the influence of GNSS spoofing signal on the innovation parameter and state estimation parameters of SINS/GNSS tightly integrated navigation system as the constraint condition. Finally, the GNSS spoofing signal generated by the covert spoofing mathematical model is used to spoof the SINS/GNSS tightly integrated navigation system. Simulation and experimental results verify the effectiveness and correctness of the proposed method. In the future research, we will further promote the experiment and application of spoofing technology in the control of various illegal unmanned platforms.

A novel nonlinear attitude error model based on square root cubature information filter (SR-CIF) is proposed aiming to speed up the convergence rate of DVL-aided strapdown inertial navigation system (SINS) in-motion initial alignment for autonomous underwater vehicle (AUV) when both large initial heading error and large initial level attitude errors exist The new nonlinear attitude error model and measurement model are applicable for initial alignment after a short-time coarse alignment with large attitude errors exist. The SR-CIF embeds the whole iterative process into the data structure framework of the information filtering, replacing the covariance matrix in the square root cubature Kalman filter (SR-CKF) with an information matrix which simplifies the filter initialization. The square root technology ensures the symmetry and positive definiteness of the information matrix with enhanced stability of the filter. The simulation and experimental results indicate that the proposed DVL-aided alignment filter is effective with large initial attitude errors. The rate of convergence and estimation accuracy of the SR-CIF is higher than that of the conventional SR-CKF with large attitude misalignments.

To deceive Inertial Navigation System(INS)/Global Navigation Satellite System(GNSS) integrated navigation terminals, the entry point is still to inject GNSS spoofing signals to the target system. However, the spoofing control strategy in integrated navigation mode for particular tasks such as fixed-point capture or directional drive needs further research. Whether applying GNSS spoofing attacks or not, the Kalman filter correction gain matrix element in the tightly coupled navigation system always maintains its stability, which gives us valuable clues to develop an effective spoofing attack. On this basis, this article focuses on the feasibility and operability of spoofing attacks under tightly coupled navigation conditions and innovatively proposes a spoofing control strategy that can achieve accurate position offsets: Specific spoofing signals are implanted to the target tightly coupled navigation terminal at the beginning of the spoofing attack. The amounts of pseudo-range spoofing signals corresponding to different satellites are respectively the projections of the position increments to be deceived on the sight vector of the integrated navigation terminal to each satellite. Simulation experiments and tightly coupled navigation terminal experiments verify the correctness and effectiveness of the spoofing control strategy.