LotOBS

From the 2004 version of the MicrOBS, we have developed equipment capable of recording 1 to 4 components (one hydrophone + three short-period geophones) for 4 months with a 6-month deployment. An update should allow us to achieve a 12 month monitoring period in 2020.

The LotOBS characteristics are similar to those of the MicrOBS, the main modifications are:

  • storage capacity 62 Go instead of 8;
  • clock precision around 2.10-8 instead of 3.10-8;
  • the geophones are located outside the sphere in direct contact with the sediment.
General

General

Maximum depth

6000 m.

Weight in air

50 kg

Weight in air with ballast

75 kg

Weight in water

- 8 kg

Weight in water with ballast

17 kg

Dimensions (H/L/W) in mm

700 / 550 / 550

Sensors

Sensors

4 components

1 hydrophon & 3 geophones

Hydrophone sensitivity

- 160 dB ref. 1 mV/microPa

Hydrophone LF-3dB

2 Hz

Hydrophone full-scale signal

70 Pa

Geophones

3 axes

Geophones type

4.5 Hz (-3 dB)

Geophone sensibility

22.4 mV/mm.s-1

Geophone full-scale

+/- 0.38 mm.s-1

Acquisition

Acquisition

Seismic channel

4

Resolution

24 bits

Sampling frequency

25 à 250 Hz

Measurement bandwith

DC to 0.40 x f sampling

Preamplifier gain

Variable from 1 to 64

Clock

3.10-7 (0.3 ppm) or 5.10-8

Correction of clock drift

linear drift correction

Synchronisation interface

DCF 77 (GPS signal)

Storage

32 Go (IDE SSD disk)

Configuration interface

RS232 (9 600, 1, 1)

Energy

Energy

Alcaline or lithium pack

Li-Ion battery

Electric consumption

0.7 W recording, 0.3 W low power

Autonomy

Recording 4 months

Deployment 6 months

Release

Release

Width

Titanium mini-release + electronic integrated release

Acoustics

Seismic hydrophone

Maximum depth

6 000 m

Localization

Localization

Flash

Novatech (ST 400-A)

Gonio VHF

Novatech RF700A-1VHF 156.625 MHz