Research On UAV Multi-sensor Integrated Navigation Technology In Interference Environment

The flight reliablity of industrial UAV is the basis for the UAV to complete its tasks.The external interferences which disterb the flight stability of the UAV are almost GNSS interference and magnetic interference.In order to detect-and-eliminate the effects of these two kinds of interference,a set of optimization methods for multi-sensor integrated navigation technology in interference environment is proposed to improve the flight reliability of the UAV when the interference occurs,and the flight experiment is designed to verify these solutions.The main work of this thesis are given as follows:1.A fusion algorithm for two GNSS data is proposed.This article uses two multi-frequency GNSS receivers,one is DGNSS with dual antenna and the other is point positioning GNSS.DGNSS is more accurate and single point GNSS is more reliable.The two GNSSs are fused uses the weights which calculate online,so that when one of the GNSS is jammed,the other one can be smoothly switched.2.A GNSS interference detection and processing algorithm was designed and verified by flight experiment.When both two GNSSs are all interferenced(eg.GNSS jammer interference)and fail,magnetic compass heading measurement and optical flow velocity measurement are used as backups of GNSS heading,velocity and position observation,and smooth switching is achieved.3.A magnetic compass anti-hopping interference algorithm was designed and verified by flight experiment.When the magnetic compass fails due to hopping interference,the DGNSS dual antenna heading value or the visual navigation system heading value is used as a backup of the magnetic compass heading observation and smooth switching is achieved.4.A magnetic compass self-calibration method for a multi-rotor drone is proposed.When the error of the magnetic compass heading data is detected,the drone would do a specified maneuvering flight and then uses the ellipse fitting calibration algorithm to correct the magnetic compass observation data.5.A method for detecting magnetic interference by the feature of flight track is proposed.the heading data error will cause the flight track error.The error feature is analyzed based on the drone’s dynamics model and used to detect the magnetic interference.This method is suitable for situations where there is only a point positioning GNSS.