Towed LandStreamer is a receiver array, specifically designed for land seismic surveys. Towed techniques for land shallow seismic acquisitions significantly increase the efficiency and reduce the cost of the survey. Such methods as reflection, MASW, refraction would highly benefit from using towed streamer, comparing to the streamer with geophones, planted in the ground.

Although, highest data quality can be achieved by dragging the streamer on solid terrains, such as roads or runways, it can also be used in the more complex conditions, such as sandy dirt roads.

The design of the streamer is exceptionally robust and easy-to-use. Steel plate with additional legs ensures the required coupling for ground motion registration. Any type of geophones can be used with the LandStreamer – vertical, horizontal, horizontal compensated, multicomponent (3C).

LandStreamer is compatible with any multi-channel seismograph and can be manufactured with the required number of receivers and the step between them. An important feature of the design is the ability to quickly disconnect the seismic receivers from the platform.

DAQLink-4 is a cutting-edge performance portable multichannel 24-bit digital seismograph. It can operate as a stand-alone unit for small and fast near-surface surveys, acquisition system for larger projects with online monitor and data quality control, as well as passive monitoring and automated event detection. Multiple trigger, synchronisation and data storage modes allow to use DAQLink-4 for all types of modern marine, land and borehole seismic acquisitions, including:

• Near-surface reflection and refraction surveys
• High resolution marine seismic acquisitions, including continuous recording shooting
• Cross-hole testing and tomography (CST)
• Vertical seismic profiling (VSP)
• Active and passive MASW
• Large-scale seismic reflection surveys
• Seismic surveys in mines
• Passive seismic monitoring.

Each DAQLink 4 unit can have 6 to 24 independent channels. The DAQLink 4 system uses standard Ethernet network connections and standard TCP/IP network protocol. Using its Ethernet hardware, multiple DAQLink 4 units can be connected together for increased number of channels. Also, DAQLink 4s can be connected to any standard network configuration.

DAQLink-4 features:

• Exceptional performance: high speed ADC – up to 64.000 sps; wide bandwidth from DC up to 20 kHz, low noise level – less 0.2 µV RMS @ 500 sps
• Easy combination of multiple DAQLinks for larger number of channels
• Compatible with any type of source
• Multiple trigger options for various acquisition types: TTL pulse, GPS time trigger, trigger by LTA and STA and others.

Multiple data storage methods:

• VHF/UHF Radio synchronisation for Underground Use
• GPS Clock synchronisation for Autonomous Recording
• Built-in instrument and sensor testing
• Data formats: SEG-Y, SEG‑D, SEG‑2, ASCII or MiniSEED

Examples of seismic surveys using DAQLink-4 seismographs:

Multiple node system, Vibroseis land survey, Impulsive source survey.

Large-scale seismic survey, Downhole acquisition, Stand-alone operation.

Various options of DAQLink-4 Networking:

• Wired option
• Ethernet 10/100 switches and cables (100 meter maximum length)
• Ethernet Extenders – can operate up to 1 km on twisted pair
• Wireless network –WiFi – Typical line of site operation or 100 meters between stations
• 900 MHz WiFi – Typical 1 Km between stations

48-channel System using Ethernet Extenders Switches.

96-channel System using Wireless/Wired Network.

Autonomous OperationMultiple DAQLink 4 units can be operated in a fully autonomous mode. No Network cable or computer is required.Data is stored in each DAQLink 4 unit, to be downloaded after the survey is complete. The data is downloaded using the “Data Collector” software and then shot record files are created using the “Harvest” software.

The GPS on each unit provides synchronization timing of the two units. The picture shows a 48-channel refraction system.