Study On The Influence Of Marine Environment On GPS Multipath Effect

The 21 st century is the century of the ocean.China has proposed the strategy of a maritime power and the “ The Belt and Road ” strategy.The application of high-precision GPS positioning in various maritime activities is becoming increasingly widespread,and the multipath effect is affecting GPS high-precision positioning.It is an important source of error,which is difficult to eliminate through modeling or observation difference.The multipath effect is closely related to the observation environment.The water surface has a strong ability to reflect electromagnetic waves.Therefore,it is necessary to reduce the Path effects are studied.This paper studies the pseudorange multipath effect and carrier phase multipath effect in GPS positioning under marine environment.Anubis software is used to extract the pseudorange multipath error,and the carrier phase multipath error is calculated based on non-difference and non-combination precise single-point positioning.The comparison method of dividing the land and sea ranges explores the GPS multipath effect in the marine environment.The main work of this article is as follows:1.The reasons for the multipath effect are introduced.The calculation method of pseudorange multipath effect is derived.The main factors affecting the multipath effect are summarized.The two commonly used quality inspection tools TEQC and Anubis are introduced.2.Carrier phase multipath error calculation based on undifferenced and uncombined PPP.A mathematical model of undifferenced and uncombined PPP is given.Various error terms are introduced and corresponding corrections or treatments are given.Method,the least square method and Kalman filter commonly used in parameter estimation are deduced.3.Based on the observation data of IGS station,COCO Net GPS observation network station and self-erected station,use Anubis software to obtain the pseudo-range multipath effect,divide the sea and land range by satellite azimuth,and then analyze the pseudo-range in the ocean and land environment.The distance multipath effect is compared and analyzed,and it is found that the pseudorange multipath effect has a negative correlation with the satellite height angle as a whole;the P1 and P2 code pseudorange multipath errors in the marine environment are not significantly different from those in the land environment;The multipath error in the marine environment is greater than the terrestrial environment.4.Calculate the carrier phase multipath effect using undifferenced and uncombined PPP,and combine the satellite azimuth to divide the sea and land areas.Compare and analyze the carrier phase multipath effect in marine and land environments,and find that the carrier phase multipath effect is overall It is also negatively related to the satellite altitude angle;there is no numerical difference in the carrier phase multipath error between the two environments;at low satellite altitude angles,there is a frequency difference in the carrier phase multipath error between the marine environment and the terrestrial environment.The frequency of the carrier phase multipath error in the environment is higher than the frequency of the multipath error of the download wave in the terrestrial environment.