METROLOGICAL SUPPORT OF IONOSPHERIC AND RADIOMETRIC MEASUREMENTS OF THE NATIONAL SURVEY OF SEISMIC PROTECTION UNDER THE GOVERNMENT OF THE REPUBLIC OF ARMENIA

The metrological support of metering means installed at the NSSP observation network sites presents an essential factor for collecting and surther processing of reliable earthquake prediction information.The following systematic measurements are carried on in the NSSP: ionospheric, radiometric, water level changes (hydrodynamic), electrometric ( irreversible polarization processes in geological media), geomagnetic, geochemical and seismological.Geophysical and seismological parameters measured at the observation sites are transmitted to the NSSP unified Centre of data acquisition and processing via radiotechnical, telemetric and satellite systems.The metrological support of ionosphere and radioinetric measurements is discussed in the presented contribution.The ionospheric measurements are made using the ۴۷-۹ and ۴۷-۳۸ receivers that work out the phase of used radio signal with the help of Rubidium frequency standard. The latter has an instrumental error comprising ۲ * ۱۰-۱۰ of the accuracy of the ۱۰۰ kHz, frequency reserence signal. The receivers provide an uninterrupted reception of the "Omega" International Navigation System signals ۲۴ hours a day. The reception is made at the fixed frequencies and within the range of ۱۲-۱۳ kHz from the four stations, namely: Liberia, Reunion, Norway and Japan. The information is stored in the electronic computer memory in an "on - line" mode, while the visual record is simultaneously made with a self - recorder. In accordance with technical descriptions calibration of the receivers used is performed by means of sample srequency comparator, an integrator and other auxiliary metering devices which provide for the certification of receiver parameters within the range of ۱*۱۰* - ۱* ۱۰% of the measured value relative error. The main registered earthquake prediction parameter for the ionospheric measurenients is represented by phase shift. To perform constant calibration of this parameter we designed a phase shifter block allowing for continuous control over the output signal phases ranging from O to ۱۰۰ us. The phase shister is sed by ۹V DC voltage and has three outputs with the voltages of ۵mV, ۵uV and ۰,۲uV, respectively. Figure ۱ presents an inspection block scheme for the ۴۷-۹ and ۴۷-۳۸ receivers using the phase shister.