Research On Data Fusion Of GBAS And ILS

As a new generation aircraft precision approach and landing navigation system recommended by the International Civil Aviation Organization(ICAO),the GroundBased Augmentation System(GBAS)has many advantages.However,strong interference such as ionospheric storms will make GBAS unable to provide accurate navigation information,which will affect the normal approach and landing of aircraft and cause safety threats.Instrument Landing System(ILS)is currently the main precision approach and landing navigation system used by civil aviation.However,the working principle of ILS makes it more sensitive to terrain.The accuracy of ILS navigation is susceptible to interference from multipath effects,which may affect the normal operation of flights and even cause safety hazards.In this paper,the data acquisition of GBAS and ILS is studied,the time alignment of GBAS and ILS is explored,and the spatial alignment method of GBAS and ILS is proposed.On this basis,the joint sharing of GBAS and ILS is realized by using data fusion algorithm,which improves the overall performance of navigation,and enables GBAS and ILS to provide navigation information that meets the requirements of category I precision approach accuracy under interference conditions.The main work of this paper is as follows:1)The data acquisition of GBAS and ILS is studied.The flight data interaction and analysis system is developed with Python based on X-Plane and its data interaction protocol.In addition to the general data,non-general specialized data of the X-Plane can be collected and stored in real time as needed by this system,and the collected data may be analyzed and played back.The verification of simulated flight data shows that the required flight data can be collected by the designed system with specified precision.The collected flight data can be used for GBAS and ILS data fusion research.2)The time alignment of GBAS and ILS is studied,the deviation indication methods of GBAS and ILS are deeply explored,and the spatial alignment algorithms of GBAS and ILS are deduced in detail.The flight data interaction and analysis system is used to collect flight data from X-Plane to simulate and verify the space alignment algorithm.As show in the simulation results,the navigation information of GBAS and ILS can be effectively converted to the unified reference by the proposed space alignment algorithm.The necessary theoretical support for the data fusion research of GBAS and ILS is provided.3)The influence of ionospheric storm on GBAS and multipath effect on ILS are studied.The motion model of aircraft in approach and landing stage is established.A data fusion method of GBAS and ILS based on Sage-Husa adaptive filtering and learning algorithm for variance estimation is proposed.The simulation results show that this method can effectively suppress the influence of ionospheric storm on GBAS and the interference of multipath effect on ILS,so that the navigation system combined with GBAS and ILS can provide horizontal and vertical guidance for aircraft to meet the requirements of category I precision approach accuracy under the interference condition,and ensure the aircraft to land safely.