noun
A specialized surveying instrument used in artillery for measuring horizontal and vertical angles to determine target positions.
砲兵隊は地上標定機を使って目標の座標を測定した。
The artillery unit used a theodolite to measure the coordinates of the target.
The loanword セオドライト is the general term for a theodolite in surveying, while 地上標定機 specifically refers to its use in artillery for ground positioning.
Compound of 地上 (ground) + 標定 (positioning, orientation) + 機 (machine, instrument). The term is a technical coinage for a ground-based positioning device used in artillery.