Constellation Design Research Of Ocean Remote Sensing Using GNSS-R Signal

GNSS-R is a new technology branch developed since the 1990 s.Some of the physical information on the surface of the reflective medium can be directly reflected in the received GNSS reflected signals.Accurate estimation and processing of the GNSS reflection signals can realize the calculation and inversion of the physical characteristics of the reflector,and it can lay a theoretical foundation for the remote sensing of the ocean.Therefore,it has been paid close attention to the research scholars in the field of satellite navigation and remote sensing.GNSS has many characteristics,such as multi-signal source,all-weather,all-day and multi-coverage.The use of satellite GNSS-R receiver for global ocean remote sensing has great potential and research value.In this study,this paper mainly studies the constellation structure of LEO-R,which is equipped with GNSS-R receiver.By analyzing its coverage of typhoon scene in Chinese sea area,this paper provides a new microwave remote sensing technology for typhoon monitoring system which means to enhance the application and development of GNSS-R technology in China's marine remote sensing field.This paper systematically expounds the principle,characteristics and advantages of GNSS-R technology,the research status at home and abroad,and describes the system characteristics of Walker constellation architecture,and introduces the functional characteristics of STK software.The GNSS-R technology and the surface scattering characteristics of the sea surface are studied.The geometric relationship of the GNSS-R system is described and the reflection characteristics of the GNSS-R signal are analyzed.In this paper,GNSS-R simulation system composed of GNSS signal source simulation module,LEO-R constellation design module,multi-source mirror algorithm module and Chinese sea area coverage capacity analysis module is established,and the structure and function of each module are introduced in detail.Taking the GPS system and BDS system as an example,the LEO-R constellation parameters such as the meridian span of the constellation,the height of the constellation,the orbit of the constellation,the number of constellation and the number of constellation satellites areanalyzed by the control variable method,and this paper describes the distribution of the reflection events in the Chinese sea area on the meridional and latitudinal zones.Finally,the super-typhoon "Morandi",which was invaded in Chinese sea area in 2016,is used as the object of study,and the LEO-R constellation with good distribution of reflection events was constructed according to its latitude and longitude range.The change rule of reflection events in the range of typhoon movement of "Morandi" is analyzed,and the number of reflection events is simulated in different weft monitoring distances,and the coverage performance of LEO-R constellations is verified.The results show that the LEO-R constellations constructed in this paper have better coverage of typhoon in China and meet the requirements of accurate warning of typhoon trajectories.