Reduction of auto seismic oscillations of the ballistic laser gravimeter on account of the excitation of the induction-dynamic catapult by a pulse packet

Abstract

In order to reduce auto seismic oscillations in the ballistic laser gravimeters (BLG) with a symmetric method of measuring the gravitational acceleration (GA), an induction-dynamic catapult (IDC) is used, which is excited by a pulse packet from a capacitive energy storage unit (CES). With such excitation, a decrease in the amplitude of auto seismic oscillations is achieved by reducing the amplitude and increasing the duration of action of the electrodynamic force that occurs in the IDC when pushing the test body (TB).A mathematical model of the IDC of the ballistic laser gravimeter with a symmetric method of measuring the GA is developed and the modeling of its electromechanical characteristics is carried out. Various methods of generating a packet of excitation pulses of the IDC inductor are considered and the characteristics of electrodynamic force pulses that accelerate the armature of the catapult with TB are investigated for them. The effect of IDC excitation by a pulse packet on the auto seismic component of the GA measurement is investigated. It is shown that on account of the excitation of the IDC by a ten-pulse packet, the auto seismic component of the uncertainty of the GA measurement by ballistic gravimeters can be reduced several (3–5) times in comparison with the excitation of the catapult by a single pulse.