A small aperture seismic group consists of three-component seismic receivers which are located at a distance comparable to the wavelength of the studied signal. Such systems are successfully used in seismology to locate weak signals from remote sources.
Here comes an earth small aperture group based on R-sensors’ equipment.
The typical structure is given at the figure.
A seismic station having the CME-4211ND broadband digital seismometer is the base of the group. Each station is connected to a communication module through a cable.
The cable provides power supply, data transfer and synchronization of the station’s internal clocks with GNSS. RS-485 is an interface of the data exchange which ensures data transfer to a distance of up to 1,200 m. Optionally, fibre-optic lines to transfer data farther than 1,200 m can be used. The SeedLink standard protocol is used to further data transfer.
The communication module consists of the NDAS-RT digital module and a power source. Extra network equipment can be set up depending on the network configuration.
Characteristics Delivery and warranty
|Frequency range||0.033 Hz (30 sec) - 50 Hz|
|Sensitivity||2000 V / (m/sec)|
|Clip level||±7.5 mm/sec|
|Self noise at 1 Hz||2.5 nm/sec|
|Dynamic range||127 dB|
|Supply voltage||5-12 V Nominal (4-17 V permissible)|
|Power consumption||300 mW|
|Temperature range||-20°C - +85°C - standard SD-card|
|ADC sampling rate||1, 5, 10, 25, 50, 100, 125, 250, 500, 1000 Hz|
|ADC resolution||24 bit|
|Hydrophone sensitivity||1000 µV/Pa|
|Hydrophone frequency range||0.033 Hz - 50 Hz|
|Hydrophone self-noise in the bandwidth||0.01 Pa|