GNSS High Precision Real Time Kinematic Positioning Technology

With the development of global navigation satellite systems(GNSS)and network communication technologies,the demand for rapid acquisition of high-resolution geographic information data in public life is increasing.From self-driving cars to real-time remote control,various new cases are driving huge improvements in positioning information in terms of accuracy,speed,and usability.Unmanned Aerial Vehicle(UAV)aerial survey technology is widely used in infrastructure,patrol inspection,police use,vegetation protection and other fields due to its flexibility,efficiency,speed,and low cost.Improving the accuracy and efficiency of UAV aerial survey is a problem that has been committed to breakthrough in the field of UAV aerial survey.In recent years,real-time kinematic(RTK)high-precision satellite positioning technology with carrier phase differential technology as the core has developed rapidly in the field of surveying and mapping.The combination of UAV and RTK technology can greatly improve the accuracy and speed of UAV aerial survey operations.Compared with traditional UAV aerial survey operations,it has the advantages of high data reliability,almost zero cumulative error,and fast operation speed.On the one hand,it greatly improves the efficiency of traditional RTK field operations,and can easily complete operations in areas where traditional RTK positioning technology is difficult to operate.However,the drone equipped with RTK technology brings great convenience and advantages,but also brings problems to be solved.The flexible and high-speed dynamic characteristics of the drone have higher real-time dynamic solution performance requirements for traditional RTK positioning technology.With the title of " GNSS High Precision Real Time Kinematic Positioning Technology",it solves the technical problems faced by RTK positioning technology carried by UAV,focusing on the research of carrier phase differential signal processing technology for multisatellite systems,High-precision RTK fast real-time solution method.The main works of the paper includes:(1)The multi-band GNSS carrier phase differential signal processing technology is studied.Through in-depth analysis of the signal characteristics of each GNSS system,the image interference suppression and IF frequency selection of the low-IF structure receiver are studied.On this basis,the RF front-end modules compatible with GPS L1/L5,Galileo E1/E5 a,GLONASS G1 and Beidou-3 B2 a band are designed.This paper used RF simulation software to analyze the reliability of the designed front-end module performance indicators,and at the same time describes the GNSS baseband data processing technology that meets the high-speed dynamic characteristics of the UAV.(2)Aiming at the fast resolution of high-precision RTK positioning of multi-band GNSS signals,the ambiguity fixing strategy adapted to the highly dynamic positioning environment of the UAV is studied.The ambiguity fixed algorithm is organically combined,and a threefrequency carrier phase ambiguity fast resolution method suitable for UAV RTK positioning is proposed.Finally,the effectiveness of the algorithm is verified by the Beidou system threefrequency measured data.(3)Realized the design of GNSS receiver system and device for drone aerial survey,specifically realized the embedded system design of drone RTK main control unit,intelligent operating system transplantation and basic software development toolkit process design;Aiming at the problems in the practical application of RTK positioning for unmanned aerial vehicles,a compact battery silo structure for GNSS rover and a carrying platform device to improve the accuracy and efficiency of the reference station were designed.