新大地坐標(biāo)數(shù)據(jù)管理系統(tǒng)的開發(fā)畢業(yè)論文外文翻譯-文庫(kù)吧
2025-04-17 01:09 本頁(yè)面
【正文】 only with higher accuracy than former systems but also with three dimension coordinates which developed on internationaly defined ITRF frame． This high accuracy 3D space geodetic coordinate system will guarantee the infrastructure surveying for the first 10 years of twentyfirst eentury． After adjustment， the plate coordinate overlap accuracy of class A GPS work is better than 210。． Elevation accuracy is better than 710． Absolute accuracy is better than m． For class B work， these accuracies are better than 410， 810， and 177。1 m， respectively． The pletion of national class A and class B geodetic control work indicates that we have developed decimetre absolute 3D geodetic control work． A new reference system is available for our space technology， and spatial data as well as real Proceedings of ISM 12th International Congress time dynamic positioning． A lot of local coordinate systems were developed besides national plane coordinate system． These systems served national economic developments in some sense． Considering the importance of coordinate system to economic developments and national defence， coordinate system factors are confidential data． The national and local governments control the geodetic coordinate factors strictly and data processing is also charged by relative government agencies． 2 MODERN SURVEYING TECHNOLOGY REQUIREMENTS FOR COORDINATE SYSTEM MANAGEMENT Requirements with advances and applications Of GPS GPS has been playing an important role in surveying and mapping from 1990 s and the accuracy is getting better． The US GPS real time positioning accuracy is 177。3 m． As a military targeted system， SA was carried out on the beginning of GPS system and was removed on May 2020 to meet its economic benefits． The US government provides higher accuracy of 177。30 m from earlier 177。100 m total standard users． A new Global Navigation Satellite System(GNSS)was in March 26， 2020 by European Union(EU)to meet their own benefits． Galileo is a program independent of US GPS developed by EU． According to its plan， Galileo program will include 30 satellites with four phases． The first phase is system evaluation period(pleted in 2020)； the second phase is development and test period(from 2020 to 2020)； the third phase is implementation period(2020 to 2020)； and the fourth phase is mercial operation perod(from 2020)． The characteristics of Galileo are its civil purpose and high accuracy． Free of chargeusers can reach177。6 m and charge users177。1 m which means an accuracy of 177。1 m global satellite positioning system will be available in 2020． The popularly used coordinate systems now in our country are 1954 Beijing system and 1980Xi’an system and 10cal systems are also based on these two systems． National coordinate system is actually national astronomic geodetic work． The national geodetic control point accuracy is far from the accuracy of 177。l m due to the restrictions of technologies． So it is urgent to upgrade our astronomic geodetic work with modern surveying technologies． The popularity and applications of global satellite require open coordinate management system． For the historic reason， coordinate management in many areas in our country is still with restriction and coordinate factors are confidential dat
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