INFRASONITUS - INFRASOUNDS ARRAY MONITORING SYTEM

The 8 channels receiver

Infrasonitus is a new infrasound sensors array system, based on optical fibre transmission, that has been realized to monitor the infrasounds activity (see the application section). The system is composed by an 8 channels receiver central station, recording data from maximum 8 low power sensor nodes, measuring the following parameters:

Infrasound signal (16 bits)
Temperature (1°C accuracy)
Voltage of battery (8 bits)

The infraound sensor node

The infrasound signal, acquired by a suitable microphone, is filtered by an active, low noise, 5 order, 20Hz low pass filter, then it is acquired by a 16 bit ADC at a rate of 50 samples/sec. The user can set an amplification factor of 0,1/0,5/1/10.

The infrasound monitoring system includes a full diagnostic functionality that performs an exhaustive test without use of other devices: this is a very important function for systems installed on the volcano flanks at high altitudes. The diagnostic system shows the integrity of the optical fibres communication lines, and the battery charge status of each connected node sensor. A new feature of this system is the low power consumption of the single node which allows to collect data continuously for one year at least, using only a 60 Ah gel battery as power supply.

Each sensor nodes transmits data to the receiver central station by means of an optical fibre, assuring the best SNR and the network integrity against dangerous atmospheric agents, as lightning. Thanks to this solution each node is also electrically insulated from the others, guaranteeing the correct system working even if one or more sensor nodes break down.

INFRASOUND GPS MIXER - (COMING SOON)

The monitoring of the volcanic activity requires the installation of a measure system in places where there isn't an electrical network, so all the systems installed use gel batteries, and optionally a solar panel, as power supply. The success of a monitoring campaign depends on the low power technology of the electronic devices used, since they have to work continuously for at least one year using only the battery energy. The date and time are very important to merge data coming from different monitoring system. Commonly it is used the date and time acquired by a GPS receiver, but usually a GPS receiver needs a lot of energy to work (about 60mA @ 5V).

The GPS receiver usually is installed on the measure system on the volcano, so it uses the battery energy to work. Our innovative GPS MIXER can be installed near the radio-modem of the base station that receives the data flow, so it can be supplied by the electrical network.

The GPS MIXER:
1) Receives and unpack the data packets received
2) Acquires the GPS date and time
3) Mix the data received from monitoring system with GPA date and time
4) Send all data to the PC

All this process is performed by an high speed custom digital electronic system, this solution guarantees the right synchronism between the data and time. Thanks to our innovative GPS MIXER it is possible to increase dramatically the life time of the batteries installed on the volcano, obtaining a perfect time coherence between the data and the GPS time.