Performance Evaluation Of Augmentation Services Of QZSS And BDS

At present,GNSS is developing rapidly and can meet the basic accuracy requirements of mass users.However,in some high-precision industries,the performance of existing GNSS needs to be continuously improved.In order to meet the needs of various users,various satellite navigation enhancement technologies and systems have emerged one after another,and the service performance of various augmentation technologies and systems has attracted users’ attention.On July 31,2020,the Beidou-3 global satellite navigation system was officially opened,and enhanced services were provided to users in China and surrounding areas.QZSS is a regional satellite system in the Asia-Pacific region,and augmentation services are one of its highlights.This paper evaluates the augmentation service performance of QZSS and BDS.The main research work and conclusions of the paper are as follows:(1)The research background and significance of satellite navigation augmentationt technology are introduced,and various enhancement services of QZSS and BDS are introduced.The basic principles of pseudo-range single-point positioning and precise single-point positioning are introduced in detail,including mathematical models,parameter estimation methods,error correction items,etc.,and the corresponding error item correction methods and related formulas are given.(2)Introduced the related algorithms for the recovery of real-time orbital clock errors of various augmentation services and related algorithms and evaluation methods for the accuracy of space signals,and evaluated the real-time orbital clock errors after the recovery of augmentation services of QZSS and BDS.The SBAS evaluation results show that the orbit,clock offset and SISRE accuracy of the L1 SBAS augmentation service BDSBAS are better than MSAS;the orbit accuracy of the Beidou DFMC SBAS corrected BDS-3 satellite in radial,tangential and normal directions are 0.089 m,0.330 m and 0.358 m,the clock error accuracy is 1.7 ns,and the SISRE accuracy is 0.52 m.The evaluation results of the PPP augmentation service show that the orbit accuracy of the QZSS MADOCA enhanced service,CLK93 SSR product,and IGS01 SSR product after restoration is at the centimeter level,and the clock error accuracy is at the sub-nanometer level,but the clock error accuracy of CLK93 is the highest,and the SISRE accuracy of CLK93 is the highest,QZSS MADOCA comes next,and IGS01 has the worst accuracy.(3)The positioning algorithms of various augmentation services in QZSS and BDS are discussed,and the positioning performance of QZSS and BDS augmentation services is compared and evaluated through calculation examples.The results of SPP augmentation service positioning show that: in Japan,both MSAS and SLAS services can significantly enhance positioning performance,but the latter has a better improvement effect and a higher improvement rate.The L1 SBAS service of MSAS has a greater increase in the elevation direction,and the L1 SBAS service of BDSBAS has a greater increase in the horizontal direction.After the enhancement of Beidou DFMC SBAS service,the horizontal positioning error RMS is about 0.60 m,and the elevation positioning error RMS is about 1.00 m.The results of PPP augmentation service positioning show that all three wide-area augmentation schemes can realize real-time PPP,and the positioning accuracy is within 5 cm.There are only differences in positioning accuracy and convergence time,but the difference is not very large.CLK93 SSR product has the highest positioning accuracy,MADOCA SSR is the second,and IGS01 SSR product is relatively inferior.CLAS can achieve PPP centimeter-level positioning accuracy,but the positioning accuracy and convergence speed are slightly worse,and the positioning accuracy is within 10 cm.