Light at the end of the tunnel

在全球范围内，正在建造越来越多的隧道（以及更长的隧道）。目前，世界上最长的隧道是瑞士的57公里（35英里）长的Gotthard基座隧道，但这在数十年中可能会改变计划的123公里（76英里）的海底隧道达利安和扬泰的中国城市。每个隧道项目都是数百万美元的投资，隧道测量所需的准确度不断增加。当预计火车以高达300 kph（186 mph）的速度行驶时，必须以最高的精度维护计划的隧道轴。如果在汉堡的ELB隧道等地下水中建造隧道建设，则必须将巨型隧道钻孔机驱动到特殊的水域构造中，并在完成后以厘米精度驱动。在研究这一规模的关键项目时，标题中最小的定向错误可能会导致大量的技术问题和财务风险。

隧道测量师在确保隧道的突破精确发生在指定的目标点上起着至关重要的作用。挑战是指导隧道的两侧朝正确的方向引导。使用细长的遍线进行定向传输的测量结果，该线只能连接到隧道入口处已知点的控制网络。无法检查隧道对面前进的方向精度。随着隧道长度的增加，配置两端以正确的隧道方向的正确性会导致相当大的风险和不确定性。

Surveying under difficult conditions
Many tunnel tubes have entry starting shafts. From these starting shafts, fixed-point coordinates are transfered down to the tunnel's level so that the tunnel can be bored correctly and navigated toward its target, this being the other end of the advancing tunnel. This process, known as plumbing, always involves an element of risk, when transferring fixed reference points in such small and narrow shafts. If the measured data is so much as a millimetre inaccurate, this inaccuracy compounds itself and leads to considerable deviations in the lateral traversing line of the tunnel's many curves and its direction.

隧道本身的测量风险发生时n the line of sight is diverted and subject to refractive influences such as temperature differences, humidity or dust. These make measuring angles and reliable measurements difficult and errors unavoidable. This applies even more due to the fact that in most tunnels the surveying points cannot be situated in the centre of the tunnel for logistical reasons and must therefore be located at the tunnel walls. Targeting close to the wall increases the risk of refraction even further. Tunnel courses with numerous (and tight) curves also require maximum accuracy.

随着隧道长度的增加，管道和折射的错误可能会加起来多达几米，从而使您在所需位置的突破不可能。在这种情况下，经常需要大量的额外工作。

解决方案是一个“玩具”
Previously, miners and tunnel builders solved this problem using compasses. In the modern tunnels of today, however, this is not possible due to the considerable amount of iron and steel used. Initial developments in solving this problem using gyroscopes came about in the early 1950s.

几乎每个人都熟悉童年时代的陀螺仪，在玩旋转上衣时。例如，我们在日常生活中不断地使用基本的进攻原则，例如，当我们在骑车时将手从自行车的车把上摘下，然后继续直奔魔术。

Precession is the directional change of the axis of a rotating body (a gyroscope) when external forces apply torque to it. If such a gyroscope is built into a measuring device which is positioned somewhere on the Earth for a certain period of time, the Earth's gravity will act on this gyroscope as the external force during this time. The gyroscope tries to counteract this external force and to remain in its original position. If it then manages to measure these values, such a gyroscope can be used to determine the direction to the Earth's axis (cartographic north).

Written by Norbert Benecke, Volker Schäpe and Volker Schultheiss