METHOD OF DETERMINING COORDINATES OF EPICENTRE OF EXPECTED EARTHQUAKE Russian patent published in 2011 - IPC G01V9/00 G01V3/12 G01V3/16 

FIELD: physics.

SUBSTANCE: received electromagnetic radiation undergoes frequency conversion in a measurement channel. Electromagnetic field strength is periodically measured at the observation point. The differential signal of two successive measurements is determined. The differential signal is integrated. The differential signal is divided by the integrated differential signal and the obtained value is compared with a threshold value. If the obtained value exceeds the threshold, the frequency-converted electromagnetic radiation is multiplied with electromagnetic radiation received in four direction-finding channels. Harmonic signals at heterodyne frequency are picked up and phase shift between said harmonic signals and the heterodyne voltage is measured. The measured phase shift values are used to determine the direction of the epicentre of the expected earthquake in two mutually perpendicular planes using a phase method. Receiving antennae of the measurement and direction-finding channels arranged in form of an asymmetrical geometric cross with the receiving antenna of the measurement channel placed at the intersection. The heterodyne voltage is phase shifted by +90° and then used for further frequency conversion of the received electromagnetic radiation. The electromagnetic radiation subjected to further frequency conversion is phase shifted by +90° and then summed with the main frequency-converted electromagnetic radiation. The resultant electromagnetic radiation is multiplied with the received electromagnetic radiation. Voltage at heterodyne frequency is picked up and then used as the control signal for allowing further processing of the resultant electromagnetic radiation. Harmonic signals at heterodyne frequency picked up in the first, second, third and fourth direction-finding channels are multiplied with each other. Harmonic signals at double the heterodyne frequency are picked up and phase shift between said harmonic signals and the heterodyne voltage at double the frequency is measured. Rough, but unambiguous angular scales are formed using the phase difference values.

EFFECT: wider range of unambiguous measurement of angles for short length of rough measurement bases.

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