INS/Intra Flight Datalink Cooperative Positioning Algorithm For UAVs

The ability of relative positioning and time synchronization in multi-aircraft cooperative mission is becoming a new research hotspot.At present,the relative positioning and time synchronization technology with satellite navigation as the core is mainly adopted,but due to the limited anti-interference ability of satellite navigation,it is difficult to provide reliable,continuous and accurate positioning and timing ability under the environment of strong electromagnetic countermeasures.It is that bottleneck problem in the development of the cooperative technology of multi-aircraft to realize the relative position ability of the satellite navigation anti-stop environment.Aiming at the relative positioning problem of UAVs in the context of satellite navigation rejection,especially the realization of reliable,continuous and accurate positioning ability under the condition of limited sensor load and communication link.Based on the advantages of inertial navigation system and data link system in the complex antagonistic environment with strong anti-interference performance,this paper proposes the relative positioning technology and method of UAVs based on inertial navigation/data link coordination.Through the logical relationship between the observed amount of inter-aircraft data link and inertial navigation output data and the new algorithm,the cumulative effect of relative positioning error based on inertial navigation output over time is suppressed to realize the accurate relative positioning ability of UAVs.The research contents of this paper include:aiming at the acquisition of continuous relative positioning observations between the two aircraft under dynamic conditions,a bidirectional and one-way ranging algorithm based on data chain is proposed,which solves the problems of real-time transmission of observation information,ranging and time synchronization between UAVs.Aiming at the problem of inter-machine relative positioning relying on the difference of inertial navigation output data and the accumulated divergence of positioning errors with time a collaborative relative positioning algorithm based on inertial navigation and data chain was proposed to suppress the divergence of relative positioning errors in the case of pure inertial navigation and improve the relative positioning accuracy of inter-machine to a higher level.Aiming at the problem of nonlinear error in the calculation of inertial navigation and data link collaborative relative positioning algorithm,an iterative algorithm based on extended kalman cooperative relative was proposed to further improve the accuracy of relative positioning.Aiming at the problem that the reliability of the extended kalman cooperative relative positioning iterative algorithm decreases under the condition of low relative motion between machines,an optimization algorithm based on weighted rank deficit free net adjustment is proposed to further improve and perfect the dual-machine cooperative positioning algorithm.Simulation results show that the algorithm is effective.The innovation of the paper's main points include:according to the relative motion of two outstanding characteristics of the situation,put forward a kind of relative distance and inertial navigation speed observation to collaborative relative positioning technology,on the basis of the implementation does not rely on the guide of relative positioning ability;In view of that influence of nonlinear error in the cooperative position calculation process,an iterative algorithm base on the synergistic positioning of the extended kalman is proposed.