Sentinel GEO is a premium-quality accelerograph with an embedded triaxial velocimeter that was conceived for structural monitoring and seismology with budget-sensitive constraints.
The onboard MEMS triaxial accelerometer which exhibits a dynamic range > 85dB and a self-noise < 18µg/√Hz can be synchronously sampled up to 500sps.
The embedded triaxial velocimeter sensor is made of three geophones with a flat bandpass from 4.5Hz up to 100Hz, synchronously sampled at 24bit with a dynamic range that exceeds 120dB.
The contribution, in terms of performance, given by the combination of the two sensors (accelerometer and velocimeter) is considerable. In fact the greater sensitivity of the velocimeter provides better seismic information whereas the resolution of the accelerometer limits the latter and provides better results with strong motion events where the velocimeter would cause saturation.
The integrated memory bank (32 ÷ 256 GB) allows you to manage a ring-buffer for long continuous recordings as well as event data.
The data format is MiniSEED.
The system implements sophisticated trigger criteria (STA/LTA and threshold) that distinguishes false events (i.e. environment vibrations) from true seismic events.
The internal GNSS receiver allows you to create a network where all the instruments are synchronized with the absolute time.
You can connect to SentinelGeo locally via network (LAN or WiFi) or, alternatively, remotely using the internal HSPA modem (optional).
The instrument can be used as a stand-alone unit to record seismic events in the field (i.e. Accelerometric Network), or it can be used in a MASTER-SLAVE based monitoring network where multiple instruments are connected to each other; Sentinel GEO is compatible with both the Triton and Atlas and this can be useful when a superior dynamics are needed, for example, as a near field unit.
Thanks to the SeedLink protocol, Sentinel GEO is compatible with the most popular seismic analysis software: Seiscomp3, Antelope, Earthworm.
Sentinel GEO is powered by an external DC source (5 ÷ 16 Vdc) and it is equipped with its own internal battery (LiPo) which can guarantee an autonomy of 5 hours in case of a blackout. The battery is a standard 18650 and can easily be replaced. The internal HSPA modem (optional) is backed up by the internal battery.
The instrument comes in an anodized aluminum case which is rugged and shock-resistant and thus suitable for field applications. Sentinel GEO is designed with an adjustable mounting plate in order to simplify the instrument leveling.