Local Swiss reference frames

In the period from 1988 to 1995 the Federal Office of Topography swisstopo developed a national surveying system that is largely based on satellite measurement. LV95 replaces the 100-year-old national survey (LV03), based on triangulation. The fundamental point for LV95 is the geostation in Zimmerwald, near Bern.

The Swiss national levelling network (LN02), dating back to the 19th century, was conceived in 1902 with the definition of the Swiss height system. The first measurement of the network took place between 1903 and 1933, and as of 1943 it was remeasured for the second time. The reference point for the height measurements is the «Repère Pierre du Niton» in Geneva, with a height of 373.6 metres.

In the course of national survey LV95, the need for a corresponding vertical reference frame arose. LHN95 is a potential-theoretic, rigorous height system which takes kinematic phenomena (uplift of the Alps) into account and is based on rigorous orthometric heights. The origin for LHN95 is the fundamental point of national survey LV95 in Zimmerwald.

The national triangulation network (LV03) was established in around 1900 and until 2016 formed the official basis for surveys in Switzerland. The fundamental point of this network is the old observatory in Bern (coordinates 600'000 m / 200'000 m).

The national gravity network, LSN2004, is based on the existing Swiss National Gravity Network dating from 1995. This network is being continuously supplemented with new absolute and relative measurements.

Every six years, swisstopo re-measures the national survey control network. Thanks to these measurements it is possible to obtain more precise information regarding Switzerland’s tectonic stability. Almost all geodata (i.e. data with a spatial context) that are used in Switzerland are based on one of the national survey control (fixed point) networks. It is therefore all the more important to periodically re-measure these networks. State-of-the-art satellite measurement technology is used for this purpose.