Especially the tropospheric model of EGNOS system and several classical models in common use to account the tropospheric refraction.

着重介绍了目前卫星定位领域主要应用的一些对流层折射修正模型。

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It also assesses the annual running costs to be about 800m euros for both Galileo and its precursor system known as Egnos.

BBC: Galileo price rises 1.9bn euros