A novel ground tiltmeter and the prospects of its application

摘要

The design and structure details of a novel ground tiltmeter are described. A high moment of inertia test mass, suspended by the low-loss high-strength foil flexure, was utilized to construct an inertial rotational reference with a high performance in ultra-low frequency band for ground tilt measurement. Since the new technique, walk-off sensor, was used in its readout system and an active magnetic damping system kept the stability of the device, the instrument has demonstrated a sensitivity of 10~(-11) rad/(Hz)~(1/2) at 1Hz. We measured the seismic tilt noise spectrum and the instrument noise floor. Its noise floor is 2～3 order of magnitude lower than the lowest level of ground tilt noise brought about by solid earth tide. Finally the possible applications of the device in some research field are listed and described.