Cooperative Navigation Methods For Multiple Uavs In GNSS-denied Environment

Driven by artificial intelligence,research on unmanned systems is on the rise,and drones are playing an increasingly important role in the civil-military field with their superior flexibility and wide application.However,due to the size,energy and amount of information of a single drone,it is difficult to meet the task requirements of diversification and complexity,especially in the GNSS-denied environment information incompleteness makes the system face many challenges.Navigation technology runs through unmanned system tasks,and multi-drone cooperative navigation can make up for the lack of single-machine navigation performance,improve the accuracy of system navigation and positioning through the interaction of information between UAVs,enhance robustness.Therefore,this paper focuses on the research of the GNSS-denied environment of the UAVs cooperative navigation method.First of all,in view of the background that GNSS signal is not available but has ground reference point assist measurement,the theoretical framework of multi-drone cooperative navigation state estimation based on Kalman filtering is established,the absolute measurement and relative measurement of multi-drone are mathematically described,and the centralized cooperative navigation method based on high dimension Kalman filtering is deduced and verified by multi-drone simulation experiments,and the influence factors of collaborative navigation accuracy are analyzed.Secondly,in the large-scale GNSS-denied environment,the autonomous navigation method of UAV based on terrain elevation matching is studied,the terrain elevation matching is carried out by using particle filtering algorithm suitable for dealing with nonlinear problems,and the particle filter matching algorithm of fusion disorder measurement update is proposed to realize the autonomous positioning of UAV using terrain perception in GNSS-denied environment.Finally,the cooperative method of drone based on inter-aircraft ranging is studied.Only through the ranging information,the relative position information between the drones is solved by triangular positioning and indirect parity method,the correction of inertial guidance information is realized by the constraints of fixed geometric configuration,and then multi-drone autonomous cooperative navigation is realized based on the self-positioning of the drone and the collaborative way.