RE:EVOLUTION IN SEISMIC SEABED SURVEYS
www.geonodalsolutions.com
GNS Self Pop-up Nodes (SPN) technical specifications Deep-water radio transparent instrument case
Glass sphere of 33 cm diameter inlaying robust plastic shell
Seismic recorder
4 channels 24 bits ADC for each channel
User interface / data backup link
Wireless USB
User terminal
Tablet, Laptop or Desktop PC
Seismic sensors
3 orthogonal 4,5 Hz gimbals mounted geophones, one deep water hydrophone
Release command
Acoustic call or automatically by preset time
Ballast anchor release
Electrochemical with mechanical support (salt waters) or solenoid type (any waters)
Ballast anchor environmental feature
Self dissolving into natural sea components after surveying (12 kg weight)
Recording time
Up to 90 days (lithium batteries)
Detecting equipment on the sea surface
Radio beacon with GPS coordinates transmission, flash light (at night), flag
Weight
20 kg in air (without anchor)
GNS SPN’s overall performance capacity Multiple times seabed deployment/recovery without opening or recharging SPN SPN operating depth is up to 7000 m Automatic clock synchronization with GPS signals through the instrument case Wireless on/off power switch. Wireless user interface. No needs to open SPN case after transport, all preparation and tests before deployment could be done on vessel deck Automatic and manual tests of power, seismic recorder and acoustic release
GNS SPN acoustic link Real Time Location of SPN on the seabed and during ascent from the seabed
Real time vessel to SPN distance measurement by acoustic channel
Acoustic link range
Up to 10 km
Frequency range of acoustic link
9 -13 kHz
Acoustic link commands
Address command for each SPN for weak up, release, distance and return to power saving mode (acoustic reset)
Acoustic on board communication equipment
Autonomic acoustic unit «GNS», powered from 220 V or from internal batteries in waterproof case. External hydrophone with long line cable.
GNS SPNs deck test before deployment
GNS600 geophysical facility
SPN picking up after recovery from seabed
Technical characteristics of GNS SPN seismic recorder
measurement conditions : 2 msec sample interval, test signal of 31,25 Hz, temperature of 25 °С, unless otherwise indicated Number of input channels
4 differential channels
A/D converter type
24 bits for each input channel
Supported data sampling
0,25; 0,5; 1; 2; 4 ms
Input amplification of analog signal
Programmable gain amplification from 0 dB to 36 dB with step of 6 dB
High cut slope of anti aliasing filter. Filter has linear phase response
-3 -3 -3 -3 -3
DC blocking filter slope
20 dB/octave, could be switch off
Total harmonic distortion
-120 dB with amplification of 12 dB, amplitude of input signal was 0,44 V peak to peak
Equivalent Input Noise, RMS
0,5 μV at 0 dB amplification 0,2 μV at 12 dB amplification 0,1 μV at 24 dB amplification 0,04 μV at 36 dB amplification
Full Scale Input Signal
2500 mV at 0 dB amplification 1250 mV at 6 dB amplification 625 mV at 12 dB amplification 312 mV at 18 dB amplification 156 mV at 24 dB amplification 78 mV at 30 dB amplification 39 mV at 36 dB amplification
Dynamic Range
125 dB at 0 dB amplification, full dynamic range is 153 dB
Gain Accuracy:
0,5 %
Cross feed talk
< -125 dB for geophone channels; < -120 dB for hydrophone channel
Common Mode Rejection Ratio
>110 dB
DC offset
<2 μV without DC blocking filter ; <0,01 μV with DC blocking filter
Internal clock stability
Better then 10 parts per billion for temperature range from -5°С to +50 °С
Self test features
Timing accuracy is better then +/-1 msec after post acquisition correction ▪ Measurement system parameters tests ▪ Equivalent Input Noise ▪ Common mode rejection ratio ▪ Cross feed talk ▪ DC offset ▪ Real time sensor data stream visualization test via wireless interface
dB dB dB dB dB
at at at at at
103,2 Hz and -0,01 dB at 93,8 Hz for 4ms sample interval 206,5 Hz and -0,01 dB at 187,5 Hz for 2 ms sample interval 413 Hz and -0,01 dB at 375 Hz for 1 ms sample interval 826 Hz and -0,01 dB at 750 Hz for 0,5 ms sample interval 1652 Hz and -0,01 dB at 1500 Hz for 0,25 ms sample interval
Time synchronization
Support infrastructure tests ▪ Status of GPS/GLONASS receiver ▪ Air pressure value inside of instrument case, leakage test ▪ Status of compass, accelerometer and temperature sensor ▪ Measurements of voltage power supply, current consumption in different modes for seismic recorder, acoustic unit and release system ▪ Batteries elapsed time monitor for recorder, acoustic and release systems ▪ Acoustic link and release tests ▪ SD flash memory test ▪ Acquisition parameters check before recording Build in GPS/GLONASS navigation receiver, powered off during recording
Data media
SD flash card of 32 Gb
Additional sensors
Temperature Air pressure Voltage & current of power supply Compass, accelerometer Elapsed time monitor for power supply Power backup-ed real time clock
Voltage range of power supply
DC from 8,5 to 20,0 V
Main user interface
Wireless USB (non active during data acquisition)
Instrument setup before acquisition
Manually via user interface or semi automatic by sending acquisition parameter file
Additional user interface
Wired USB 2.0 HS
Data format
Blocks of multiplexed data. Convertor to SEGY during data backup
Data backup speed
Up to 15 Megabyte/sec via wireless interface
Indication of recorder performance
Color light diodes
GNS SPN outline
Technical characteristics of GNS SPN's geophone elements Natural frequency, Hz
4,5 ±0,5
Distortion*, %
<0,3
Open circuit damping
0,56 ±5%
Resistance, Ohm
375 ±5%
Sensitivity, V/m/s
28,8 ±5%
Moving mass, g
11,1
Maximal coil excursion, mm
±2
Physical sensor size (diameter x height , mm)
Ø 25,4 x 36
Weight, g
81
Operation temperature range, °С
From -40 to 100
*) Distortion measurement frequency is 12 Hz with 17,78 mm/s coil to case velocity
Technical characteristics of GNS SPN's deep water hydrophone Sensitivity with pre-amplifier
-171 dB re: 1 V/μPa
Frequency response
From 2 Hz to 30 kHz
Equivalent input self-noise RMS from 1 Hz to 1 kHz
-75 dB re: 1 μPa (or 0.06 μBar)
Spectral density re: 1 μPa/√Hz:
-54 dB at 10 Hz -40 dB at 100 Hz -38 dB at 1 kHz
Maximal operation depth
6096 m
Physical size ( diameter x height )
Ø32 mm x 38 mm