1. INTRODUCTION
Vector hydrophone is a kind of sensor which can detect the vector signals such as acoustic velocity and acceleration [1], [2]. It has low frequency directivity, high spatial gain and smaller volume than traditional acoustic hydrophone and its array. According to different working principles, vector hydrophones can be divided into differential pressure type and co-vibration type. Co-vibration vector hydrophones can directly measure particle velocity in sound field without obvious distortion of sound field, and their performance parameters are stable. They have been widely used in sonar buoy system, towed array low noise measurement and other fields [3].