Alternative to radio telescopes
Procedures used previously are based on determining the rotation of the Earth using radio telescopes and reference objects such as distant radio stars or quasars. The spatially fixed reference system of the quasars can be linked on the basis of these measurements with reference systems on the Earth as it rotates – important information for satellite-supported navigation systems such as the “Global Positioning System” (GPS) for example. However, these measurements are relatively costly and they can only be carried out in conjunction with several radio telescopes at different locations on the Earth. That is why independent alternative procedures are important.
Ring lasers are such an alternative – although not of the type that is used in compass systems for airplanes. The sensitivity of these laser gyroscopes needs to be increased by a factor of more than a thousand. The realization of the measurement principle and the technical requirements were investigated in a project study carried out jointly by the BKG, the Munich TU and the University of Canterbury, New Zealand. For this purpose a one-square meter prototype was produced by Carl Zeiss using a single piece of “ZERODUR®” made by SCHOTT. This instrument was installed and tested in 1997 in an underground laboratory in New Zealand.
Test run confirms practicability
“ZERODUR®” is the material of choice
Completion in the summer of 2001