Application Of Precise Point Positioning Technology In Antarctic Aero Geophysical Survey

The polar ice sheet plays an important role in global climate system and directly controls the height of the global sea level.So,the monitoring and detecting of the polar ice sheet is significant to understand as well as predict the evolution mechanism and evolution process of ice sheet.Because of the huge range of ice sheet and the harsh environment of polar area,the polar aero geophysical survey becomes the main expression of national capabilities and technology level.With the help and guide of American partner,the huge range of precious aero geophysical data collecting in east Antarctic study blank area?Princess Elizabeth Land?was successfully done.However,how to process and explain the collected data independently is still a big problem for Chinese researchers.This thesis focuses on the first part of the data processing of Chinese first aero geophysical survey da—the positioning data.We hope to do some researches about the positioning data post processing to provide technical support for future aero survey works.To find a better data processing method to satisfy geophysical positioning requirements.Traditional GPS pseudo-range measurements and carrier phase measurements are not effective in polar regions.The reason for this is because the polar regions have higher latitudes,and the receivable satellite signals are weaker than other regions,resulting in long initialization times,a failure to initialize or the cycle slips.The RTK technology uses the principle of difference.Although the positioning accuracy works well under normal circumstances,it is not able to provide accurate positioning in the polar regions due to the large range of the base station's radio signals.Therefore,the Precise Point Positioning?PPP?will be the best choice of the aero geophysical data post processing.When facing the polar and high-latitude area,a big bunch of experimental data will be need to examine the effect and precision of positioning.We chose RTKLIB as a main tool to process positioning data after comparing the precision of on-line process and off-line process.This paper will use the kinematic data obtained by the airborne Javad-Delta 3 high-precision GPS in the 32^nd China Antarctic expedition geophysical exploration work,and three-months of static base station data collected by two Ashtech Proflex 800 high-precision GPS installed at the Zhongshan Station Ice Sheet Airport to examine the accuracy of on-line processing?CSRS-PPP?and off-line software processing?RTKLIB?using Precise Point Positioning?PPP?.Comparing the accuracy of the different processing methods,we ultimately chose the off-line software as the method of processing all the data.We also conducted some researches about GPS signal propagation path and its correction parameters.For the important parameter settings affecting the PPP post-processing results,including filtertype,ionospheric correction,and tropospheric correction,a comparison test was conducted to summarize the best combination of polar high-latitude aero geophysical PPP processing parameter to be"combined"+"Iono-Free LC+“Estimate ZTD+Grad”.Complete all the post-processing work of GPS data about the 32^nd Antarctic scientific expedition of China.In addition,meticulous analysis to important survey line was done.By comparing and analyzing three important routes of F03,F04 and F09 and the ZGN21 base station for three months,it verifies the accuracy of PPP post-processing and proves the feasibility of the PPP technology in polar regions.Furthermore,the flow velocity and direction of the ice sheet where Zhongshan Station is located are calculated,which helps to provide a reference for the subsequent research on the ice sheet.In the end,an attempt is made to match the GPS positioning data with the geophysical data,and the specific ideas for developing the data connection software are given,which provides a framework and reference for future work.