This work is concerned with an experimental device which exhibits the characteristics of a horizontal seismometer with a long natural period using a gyroscope, the experimental device having demonstrated periods of 45 seconds and longer. This seismometer is called the gyro-transducer throughout this paper. The principles of operation described here have previously been presented. The gyro-transducer achieves long-period seismometer action through a gyroscope, an ordinary simple pendulum and an electronic feedback. With suitable device parameters the performance equations will be the same form as those of a conventional seismometer, the natural period and damping being functions of an amplifier gain. Experimental results obtained in the laboratory provide useful data to apply the gyro-transducer to a practical seismic observation system. The gyro-transducer is of interest, however, whether or not it finds use as a seismometer. It will be suggested that the principles described here should be applied to the highly precise gyroscope and the very sensitive sensing elements.

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本研究は, 極力低コストに自動直進走行システムを開発することを目的としている。航法センサとして地磁気方位センサとを採用した。本報では, 地磁気方位センサの傾斜補正用の傾斜計に静電容量タイプの傾斜計を, を採用し, 高精度な方位推定法を提案した。はじめに, 傾斜計のノイズを適応線スペクトル強調器によって除去することを試みた。次に, 圧電振動のドリフトを最小二乗法を適用することで推定した。さらに, 地磁気方位センサと圧電振動の補正出力を融合し, 高精度な方位推定法を構築した。最後に構築した手法の精度を評価するために自動直進走行試験を行った。その結果, 地磁気方位センサと光ファイバーを使用した自動直進走行と同等の精度が達成された。

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To record long period seismological movements, we proposed in the previous paper a new instrument as a precise seismometer with a dynamic long period pendulum using gyroscope and examined the various dynamical characteristics of the system subject to horizontal seismic movements.
In this paper, we consider the observation system to record the vertical component of seismic movements. In this system, we utilize a quasi-TDF gyroscope (transducer) in addition to an ordinary mass-spring system. The vertical seismological movement transferred to the torque causes the gyro-axis to precess about the perpendicular axis, and the output signal (angular displacement or velocity) is measured by a measuring instrument.
Topics in this paper are summarized as follows: 1) We analyze dynamical equations of a transducer theoretically when seismic accelerations are applied to it. And we examine the various dynamical characteristics as a seismometer. 2) We present the procedure for designing this system for practical use and provide numerical examples. 3) A digital simulation for the system is carried out and satisfactory results are obtained. 4) We present technical considerations for future development.

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In this paper, we propose our idea to open up a new field in seismology. Many practical seismometers developed up to now do not perform satisfactorily enough to record long period movements (1∼60sec) in the case of great earthquakes.
In more recent times gyroscopic instruments have been used for various purposes where limited accuracy is required.
We pay attention to the essential properties of a gyroscope such as the precession and the gyroscopic reaction moment, and propose a new instrument as a precise seismometer with a dynamic long period pendulum (proper period 2, 10, 20min) using gyroscope.
In this observation system, we utilize a vertical gyro-pendulum (transducer). The horizontal seismological movements transferred to the torque cause the gyro-axis to precess about the mutually perpendicular axes, and the precessional velocities are measured by rate-gyroscopes (measuring instruments) as amplifiers.
We examine the various dynamical characteristics as a seismometer for practical use and present technical considerations for the future development. The results obtained by the above considerations suggest that the accuracy of measurement is further improved by our new instrument.

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In recent years, considerable attention in seismology has been given to the world-wide observation of distant earthquakes and microseims. To observe long period seismic waves caused by distant earthquakes, we have developed an entirely new type of seismometer with a dynamic long period pendulum using a gyroscope. This seismometer is called the gyrotransducer throughout this paper. Our gyrotransducer consists of a gyroscope and an ordinary mass-spring system, and the range of its natural period is about 30∼60sec.
In this paper, we consider an observation system for measuring a vertical seismic motion and examine the amplitude response of a forced vibration which is the most important characteristic of a seismometer. The technical problems of this seismometer are investigated. Among them are mainly the problem of how an ambient temperature change influences the elastic constant of a spring in the seismometer and the problem of what fluctuation the zerolevel of recording suffers due to null-torque. Experimental results obtained in the laboratory and in the seismological station at Tsukuba provide useful data for us to apply this gyrotransducer to a practical seismic observation system.

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This work is concerned with a long-period vibrometer using a gyroscope, the experimental device having demonstrated periods of 46 seconds and longer. Several types of the gyro-transducer have previously been built and some of technical problems have been clarified.
The topics in this paper are summarized as follows: 1) The more compact gyro-transducer in arrangement is designed. 2) The sensitivity of the gyro-transducer is further improved. 3) The limitations imposed on the performance are considered. 4) The problem of how other components of input acceleration influences the output signal is discussed. 5) The observation can be carried out without being disturbed by long-term drift due to the thermal effects etc.

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