On the Problem of Taking into Account the Effect of Meteorological Factors on Large Precision Systems: A Case Study of the Baksan Large-Base Laser Interferometer

Variations in ambient temperature and atmospheric pressure coincide with the wave train of the lunar–solar tide in the diurnal and semidiurnal frequency ranges, where they have the greatest influence on deformation measurements by laser interferometers. Based on data from the Baksan laser interferometer of the Sternberg Astronomical Institute of Moscow University over a 15-year observation period, it is shown that the response of large measuring systems to these variations has a pronounced frequency dependence. Using the constructed mathematical model the problem of taking into account how meteorological factors influence measurements is solved in the frequency domain with the aid of images of deformation time series and meteorological factors, obtained by Fourier transform. A transient function is constructed in the form of the so-called aperiodic link, which takes into account the frequency dependence and delay of thermoelastic deformation of the measuring system on the variation in ambient temperature. The converted temperature and pressure images are subtracted from the deformation image using the corresponding transient functions. As a result, the new deformation image bears virtually no influence of meteorological factors; inverse transform yields a new deformation time series.