Seamap’s state of the art design enables customers to re-calibrate hydrophones onboard. This significant development in technology contrasts with hydrophones that boast inbuilt memory capability but actually only ever provide derived data stored at time of manufacture.
Seamap’s groundbreaking design utilizes an in-built EEPROM memory device and thermometer to enable ongoing verification of data at chosen future intervals. This up-to-date data, collected by the customer at a time of their choosing, will be stored in the hydrophone memory and can be accessed at a later date to provide traceability. This extra functionality will negate unnecessary hydrophone wastage and assist with preventative maintenance of equipment.
A hand held ‘Verification and Re- Calibration Unit’ will be available to customers for ongoing verification and re-calibration of hydrophones onboard the vessel. This unit contains a reference calibrated sound source and hydrophone to facilitate the calibration of the test subject. The hand held unit can be periodically sent off to Seamap for re-calibration, but this would only be necessary once a year at most.
GunLink software enhancement has already been planned by Seamap. Future developments will enable the software to access the EEPROM and thermometer in real-time, offline or online, display the calibration information within the GunLink GUI,and make compensation adjustments for temperature variations. This streamlined approach between GunLink and Seamap’s hydrophone range will improve reliability.
Each hydrophone, specifically designed for near field monitoring of air guns in the marine seismic environment, is characterized against a reference. The PCB memory stores this data. Characterization is performed as part of the design proving. The characterization will detail the full and exact performance of the product over a wide frequency range, temperature range, and will simulate a series of stressful shock and vibration scenarios.
Calibration will be performed at manufacture on each individual production run unit. Each Seamap hydrophone will be calibrated at a frequency over 10Hz – 500Hz. The data from this calibration is stored in the EEPROM memory on the PCB.
The units are robust and designed to remain stable in response both over time and over a wide range of acoustic exposure. Ongoing verification and re-calibration, performed by the customer, will trace any drift in capacitor induced by excessive use in the field. This live data can be verified on a project by project basis improving reliability and reducing downtime through the identification of faulty units.
Seamap Hydrophones have been independently verified by our partner and in extensive field trials.
Seamap hydrophones are fully functional with the GunLink 4000 or 2500 digital source controller, but can be purchased as a stand-alone product offering a clean signal and precision auto fire detection, even with small air leaks.