SUBSURFACE GEODETIC DATUM FOR SEASONAL EARTH FREEZING REGIONS Russian patent published in 2012 - IPC G01C15/00 

FIELD: physics.

SUBSTANCE: subsurface geodetic datum has a metal tube with a mark at the top end which is mounted in a well and placed along its axis, where the top part of the metal tube is placed over the ground level, has an additional mark and has an opening for fitting geodetic instruments. The top end of that tube is covered by a plate with a hole for forced centring of geodetic instruments. The metal tube is embedded in concrete in the well. The cavity of that tube to the lower level of said opening is filled with mortar, and its depth is determined by the level of maximum soil freezing. There is no laying of separate datum marks of the satellite network or levelling network. There is no need to use support stands for making satellite observations and levelling and satellite observation results can be verified on the same datum mark.

EFFECT: possibility of using a subsurface geodetic datum both in a levelling network and in a satellite observation network.

2 dwg