Gyrotheodolite

A Kreiseltheodolit or surveying circles List a special a geodetic measurement and gyro instrument that is used for precise measurement of direction underground.

When Kreiseltheodolit is a gyroscope to the absolute direction determination incorporated into the theodolite. This gyroscope and its suspension are located under the alidade of the theodolite. The surveying gyroscope is an add - gyroscope, which is mounted on the frame of the theodolite. Surveying gyroscope are no longer in use.

Construction

The mounted in the substructure roundabout - which is like all gyroscopes a delicate, fine mechanical device - thus has a smaller ground clearance than the other measurement units, for reducing mechanical disturbances ( shocks, vibrations, etc.) contributes. Due to this design the most Kreiseltheodolite have a compact form and need special tripods with large tripod plate depends in which hole the centrifugal cylinder.

The measuring sensor is a very rapidly rotating, cylindrical gyroscope with a horizontal axis, which is suspended on a torsion band. Such horizontal chained gyro has the property to its North seeking and becomes a torsion pendulum: The axis of rotation of the rotating body suffers through the Earth's rotation slow pivoting ( precession ) and seek to - to put parallel to the Earth - as with the gyrocompass. Under the action of the torsion this precession is transferred into a rotary vibration which occurs when the damped vibration of geographic north.

Method of measurement and accuracy

With special auxiliary devices, this vibration operation, the period is in the range of tens of minutes, analyzed, and the instrument is successively rotated to the accurate north direction. With previous instruments (eg the GK series of wild ) these Guiding was done manually by the observers analyzed the centrifugal vibration either by their turning points or by passage method or auswertete in rapid approximate method or graphically. Newer semi-automated devices rotate the gyro frame after by fine adjusting electronic circuits.

Due to the centrifugal theoretical connection to the Earth's rotation Kreiseltheodolite deliver astronomical azimuths, as well as the method of Astro Geodesy, but are slightly less accurate. The accuracy of direction measurement is (depending on the work involved the measurement series ) about 1 to 3 mGon (3 to 10 seconds of arc ). By centrifugal azimuths a similar direction stabilizing effect can be achieved as with solar or Laplace azimuths in above ground surveying networks in underground polygons. The process developed for the Ruhr mining Gyromat accuracy is achieved by some Milligon after a short time, which can be further increased by prolonged extensive series of measurements.

In principle, the accuracy could be even greater, but the market for such instruments relatively small, which has to do with other advancements of the downhole measurement technology and above-ground GPS networks. The technique is implemented for example in automatic Gyromat or in light measurement platforms for inertial navigation, would allow a measurement accuracy up to just under 1 ".

Application

Kreiseltheodolite be used in tunneling and mining in the determination of the direction of impact. Easier gyro instruments were before the advent of satellite positioning applications in the military field in the direction determination for artillery and missile units, and at the Militärtopographen, since they constitute the only way without a position of fiducial points to make accurate direction information.

Manufacturer

Manufacturers of Kreiseltheodoliten are, or were, inter alia, the company Askania (Berlin), Wild ( Heerbrugg ), MOM (Budapest) and German coal and steel technology.

Use in the French artillery

Use in the French artillery