Improving the

measurements at CZ variation stations - methods and


Janosek, M. (1), Butta, M.(1), Vlk, M. (2),

Bayer, T. (2)

(1) Dept. of

Measurement, CTU in Prague (2) Institute of Geophysics, Czech


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In this presentation, we summarize the

performance an ongoing development of instrumentation and data

processing at two Czech variometric sites at Polom (PLM) and Kelcany

(KEL). The Polom station has been running since 2017 and Kelcany since

2015, both employing low-noise, race-track fluxgate variometers of

CTU's construction.


The underground station at KEL has an advantage of being at a

passively stabilized temperature (+-5°C during a year), but suffers

from neigbouring car traffic, creating large peaks in the data. We

present a method, employing a gradiometric measurement and numerical

calculations, how to sucessfully remove most of the car traffic

signatures and improve our daily signal to noise ratio.


The PLM station is unique that it until now runs at ambient

temperatures, i.e. no sensor or electronic heating is maintained (this

years low extrema was -17°C). However, by having the instrument

calibrated and knowing the temperature drifts and monitoring the

sensor temperature, we are able to largely supress the temperature

effects on the measurements. An ongoing development of the

non-magnetic, RF based heating which is planned for the site will be

also presented.


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