Page 144 - Lehrbuch Neigungsmessung deutsch 2018.indd

COMPENDIUM INCLINATION MEASUREMENT
WYLER AG, WINTERTHUR / SWITZERLAND

Table 1 shows the gravitational acceleration in various cities around the world; amongst these cities, it is
lowest in Mexico City (9.779 m/s²) and highest in Oslo and Helsinki (9.819 m/s²).
Amsterdam 9.813 Istanbul 9.808 Paris 9.809
Athens 9.807 Havana 9.788 Rio de Janeiro 9.788
Auckland 9.799 Helsinki 9.819 Rome 9.803
Bangkok 9.783 Kuwait 9.793 San Francisco 9.800
Brussels 9.811 Lisbon 9.801 Singapore 9.781
Buenos Aires 9.797 London 9.812 Stockholm 9.818
Calcutta 9.788 Los Angeles 9.796 Sydney 9.797
Cape Town 9.796 Madrid 9.800 Taipei 9.790
Chicago 9.803 Manila 9.784 Tokyo 9.798
Copenhagen 9.815 Mexico City 9.779 Vancouver 9.809
Nicosia 9.797 New York 9.802 Washington 9.801
Jakarta 9.781 Oslo 9.819 Wellington 9.803
Frankfurt 9.810 Ottawa 9.806 Zurich 9.807

Since gravity depends on the latitude and the altitutde, the measured inclination is precise only at the
location where the measuring device was calibrated, i.e. at WYLER AG in Winterthur, Switzerland. In Sin-
gapore, for example,, where the gravitational force is smaller, the displayed angle will be below the actual
one.
The displacement of the disc can be calculated using formula (1):
(3)

where
x displacement of the disc at location of measurement
m
g gravity at the location of measurement
m
 effective angle
eff
The electronics of the sensor calculate the angles according to the place where it was calibrated. There-
fore the same formula used for the displayed angle can be used:
(4)

where
g gravity at the place of calibration
c
 displayed angle at place of measurement
m
Combining formula (3) and (4) allows forecasting which angle the sensor will show at a location with
changed gravity. Solving for the effective angle the correction factor for the displayed angle can be calcu-
lated:
(5)

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