Research On Key Navigation Technologies Of Unmanned Helicopter Under Complex Airflow Interference Environment

Unmanned helicopters have unique flight performance and use value,and play an important role in the fields of national defense and civil.Complex airflow interference refers to the comprehensive effect of atmospheric turbulence,discrete gust and wind shear on the unmanned helicopters during the flight,which will strongly affect the flight safety of unmanned helicopters,and also bring new problems to the navigation system of unmanned helicopters.For this reason,the key navigation technologies of unmanned helicopters under complex airflow interference environment are studied in this paper,in order to propose navigation methods with high accuracy,reliability,stability and autonomy,which are suitable for unmanned helicopters under complex airflow interference environment.Inertial navigation system is an important core navigation equipment of unmanned helicopters,this paper studied the inertial navigation system error characteristics of unmanned helicopters under complex airflow interference environment,firstly analyzed the response characteristics of unmanned helicopters to atmospheric turbulence,discrete gust and wind shear interference respectively,as well as the influence of calculation errors of inertial navigation system.And then analyzed the effect of IMU vibration errors on inertial navigation system of unmanned helicopters.Because the noncommutativity error caused by angular velocity integral will be increased under random vibration environment,the noncommutativity error under random angular vibration environment is analyzed.The angular rate three sample coning compensation algorithm is researched,and an improved angular rate three sample coning compensation algorithm has been proposed,the precision of strap-down inertial navigation algorithm is improved under complex airflow interference environment.Due to the inertial navigation system can not meet the requirements of unmanned helicopters for accurate and reliable navigation under the complex airflow interference environment,thus,an INS/LIDAR/GPS integrated navigation method for unmanned helicopters is proposed in this paper based on the characteristics of GPS and lidar.Based on the analysis of the geometric model of lidar,a height measurement model of lidar is established,combined with the motion characteristics of unmanned helicopters,an installation error calibration method of lidar based on unmanned helicopters hover state is designed.Considering the attitude coupling error of lidar,the integrated navigation filtering model is improved,and effectively improve the INS/LIDAR/GPS integrated navigation performance of unmanned helicopters under complex airflow interference environment.Due to barometric is widely used on unmanned helicopters for height measuring,an INS/Barometric/GPS integrated navigation method of unmanned helicopters is proposed.A pressure altitude error model under complex airflow interference environment is established.An adaptive filtering algorithm of pressure altitude drift error compensation based on GPS assistance is designed.An INS/ Barometric/GPS integrated navigation scheme for unmanned helicopters under complex air interference environment is designed,the pressure altitude measurement is modified,and the precision of INS/Barometric/GPS integrated navigation system of unmanned helicopters under complex airflow interference environment is improved.At the end of this paper,the general integrated navigation scheme of unmanned helicopters under complex airflow interference environment is proposed.Combined with the existing equipment in the laboratory,a comprehensive simulation platform for integrated navigation system of unmanned helicopters under complex airflow interference environment is designed and built.The relevant algorithms and schemes proposed in this paper are verified and analyzed by the measured data.The results show that the algorithms and schemes proposed in this paper can improve the navigation performance of unmanned helicopters under complex airflow interference environment.