Research On UAV Positioning Technology In Field Test Of Antenna Pattern Of Ground Stations

The ground station antenna plays an important role in the satellite system,whose performance is a key factor of satellite communication quality.After installation,it is necessary to conduct a field test of the antenna pattern of ground stations in order to complete the network test.Given that traditional test methods lack flexibility and controllability,this thesis proposes a new method of antenna field test by using an Unmanned Aerial Vehicle(UAV),which carries a beacon antenna and flies above the ground station.In this method,the location of the UAV is crucial information,the precision of which determines the accuracy of the direction in the antenna pattern.Focusing on UAV localization in the field test of the antenna pattern,the thesis mainly studies the following key problems:(1)Test scheme design of antenna pattern of ground stations based on UAV beacons.Based on the requirements of the pattern test,the main components of the test system are designed,and the conditions that the test scheme needs to meet are proposed.(2)UAV positioning method and error analysis.For the two mainstream passive positioning methods,the time of arrival(TOA)positioning method and the angle of arrival(AOA)positioning method,the positioning principles are described,the sources of the positioning errors are analyzed,and error transmission chains are discussed respectively.(3)Configuration design of base stations.For the TOA positioning method,optimizing the configuration of base stations is one of the methods to improve the positioning precision.In this thesis,the Position Dilution of Precision(PDOP)is improved into an optimization problem of base station configuration based on Weighted Position Dilution of Precision(WPDOP)model.To solve the optimization problem,genetic algorithm and a simplified algorithm based on nested conic configuration are adopted and the results are compared.Finally,the relationship between the number of base stations and the WPDOP value is analyzed and verified by simulation.(4)Error analysis of time delay measurement.This thesis adopts a universal measurement operator to measure time delay and analyzes the measurement error.The Cramer-Rao bound(CRLB)of time delay estimation is deduced,conditions of measurement results not falling into the "error zone" are discussed,and three requirements of measurement signal are proposed.For the spread spectrum signal,this thesis analyzes the measurement error of time delay,and verifies the conclusion by Monte Carlo method.