In spite of the technological development of the last decades in the field of the geodetic instruments,some parameters,which affect their performance,are difficult to be eliminated.One of these parameters is the geode...In spite of the technological development of the last decades in the field of the geodetic instruments,some parameters,which affect their performance,are difficult to be eliminated.One of these parameters is the geodetic refraction.The refraction describes the alteration in the direction of the light curve as it propagates through the different layers of the lower part of the Earth’s atmosphere.The purpose of this research work is to investigate the uncertainty of the refraction coefficient of a new proposed methodology.This methodology is based on:(a)the exploitation of the full trigonometric height equation,(b)the ability of the Hydrostatic Levelling System(HLS)to provide height differences with±10μm accuracy.The experimental application has been set up in a section of the underground tunnel complex at the European Organization for Nuclear Research.In this indoor application,the determination of the refraction coefficient at a Laser Tracker station using the precise height differences provided by an HLS has been performed.In addition,this methodology has been tested by comparing its results with those that have been obtained from the Temperature Gradient(TG)method for the determination of the refraction coefficient.The results are very encouraging for the efficiency of the methodology.At the same time,some limitations on the implementation of the proposed methodology have been highlighted.展开更多
文摘In spite of the technological development of the last decades in the field of the geodetic instruments,some parameters,which affect their performance,are difficult to be eliminated.One of these parameters is the geodetic refraction.The refraction describes the alteration in the direction of the light curve as it propagates through the different layers of the lower part of the Earth’s atmosphere.The purpose of this research work is to investigate the uncertainty of the refraction coefficient of a new proposed methodology.This methodology is based on:(a)the exploitation of the full trigonometric height equation,(b)the ability of the Hydrostatic Levelling System(HLS)to provide height differences with±10μm accuracy.The experimental application has been set up in a section of the underground tunnel complex at the European Organization for Nuclear Research.In this indoor application,the determination of the refraction coefficient at a Laser Tracker station using the precise height differences provided by an HLS has been performed.In addition,this methodology has been tested by comparing its results with those that have been obtained from the Temperature Gradient(TG)method for the determination of the refraction coefficient.The results are very encouraging for the efficiency of the methodology.At the same time,some limitations on the implementation of the proposed methodology have been highlighted.
