Analysis?Improvement And Adhibition Of The Software Called GLAB

Precise point positioning(PPP)technology is one of the hot topics in the research field of GNSS,and is gradually penetrating into the various application fields of GNSS navigation and positioning.In the domestic and foreign software in precise point positioning,GLAB is a versatile software for processing and analyzing data from a single GNSS station,which can compatible with SPP,static PPP and dynamic PPP.It has an open source,the interface is friendly,both suitable for beginners to learn,but also as a Research Institute of experimental software,at the same time,it can provide further improvement research service for the professionals.This paper systematically analyzed the principles and positioning precision of the software,the related algorithms of gLAB software are extracted,the main formulas are deduced,some source codes are improved,and the software is analyzed and applied.The main research contents and conclusions are as follows:1.This paper sorts out the related foundation of gLAB software,gives the non difference observation equation derived expressions,dual frequency ionosphere free combination observation equation,explains the satellite clock error,DCB,TGD etc.,and explains the other combined observations.2.In this paper,the contents of gLAB software data preprocessing are presented from 5 aspects,namely pre reading and post reading preparation,pre alignment of carrier phase,pseudo range hopping check,cycle slip detection and phase smoothing pseudorange,this paper analyzes the algorithm and data preprocessing,pointed out that the satellite arc original software division not reasonable etc.3.This paper deeply analysis the three types of positioning model correction principle,the specific content and formula of gLAB software model correction are given from the receiver end,the satellite side,the signal propagation path and other aspects,points out that the correction value is always 0 when the SPP uses the navigation ionospheric mode.4.This paper analyzes the similarities and differences of parameter solution,when the gLAB software realizes SPP,static PPP and dynamic PPP with Kalman filter formula,including parameter setting,observation equation and weighted matrix,transfer matrix and state noise,the initial epoch parameters and noise etc;presents the whole operation process of g LAB three models;points out the problems existing in the operation of the original software and the improvement direction in the future.5.This paper improves the existing problems in the gLAB source code,and compares the positioning results of the three models before and after the improvement based on the precise coordinates of the IGS station;analyzes the interface design of gLAB software,and realizes the gLAB software interface;the improved software is used to locate the ship,and the results are consistent with the CSRS-PPP.