A method to enhance the low-frequency performance of geophone

The velocity sensor is an important component of active damping systems and affects the accuracy and bandwidth of the control system. Velocity sensors with limited size lack accuracy in the low-frequency domain. To increase the velocity sensor measurement performance, this paper proposes a method that extends the low-frequency measurement bandwidth of the velocity sensor. Firstly, a mathematical model is established to obtain the physical characteristics of the sensor and analyze the factors affecting the measurement bandwidth. Secondly, an extended filtering method is introduced to match the sensor parameters and to design the sensor signal processing circuit based on theoretical calculation and simulation. Finally, a testing platform is set up and experiments are carried out. The results show that, for a given geophone with a natural frequency of 2Hz, the measurement bandwidth can be extended to 0.2Hz by using the proposed method.