分别采用双台地震计自噪声互相关分析法(以下简称“Holcomb双台法”)和3台地震计白噪声互相关分析法(以下简称“Sleeman多台法”)对CMG-3T、BBVS-120、STS-2型流动宽频带地震计进行自噪声测试研究。结果表明:Sleeman多台法因有效地规避了传递函数引起的误差,在处理流动宽频带地震计实际记录数据方面比Holcomb双台法更能有效地滤除背景噪声;在简单测试条件下,3种常用流动地震计的自噪声在0.06~1Hz频带内均低于NLNM曲线,显示了相当好的噪声性能指标;在流动台阵观测过程中,地震计方位准确性以及地震计的保温防护措施是保证发挥仪器性能的重要因素。
This article uses two-sensor coherence analysis method( Holcomb, 1989)and three-sensor coher- ence analysis method (Sleeman,2006) to calculate the self-noise models for CMG-3 T, BBVS- 120 and STS-2 seismometers. The results show that: 1 )Sleeman's method can avoid the error caused by the transfer function in calculation and can extract more potentially and efficiently the background noise than the Holcomb's method does ; 2) Under our simple test condition, the self-noise of the three sensors in 0. 06 - 1 Hz band is lower than NLNM, which represents a quite good noise performance; 3) In the observation process of movable seismic array, the sensor alignment and sensor insulation protective measure are important factors to guarantee a good performance of the instruments.