Publication Date:
2017-04-04
Description:
Seafloor clearance methods based on acoustic,
direct-inspection, and single-sensor magnetic approaches suffer from limitations in controlling the target-sensor distance, and may prove ineffective when the small size or the dangerous nature of targets requires high accuracy in localization.
Moreover, random magnetic variations over time bring about spatial decorrelation phenomena, and hinder the application of
double-sensor methods in noisy harbour environments.
The new High Definition (HD) magnetic survey protocol tackles the measurement-distance problem in two ways: first, by varying the sensor depth dynamically, and secondly by backprojecting the measured field according to seafloor data and vertical incremental factors associated with the bandwidth
characteristics of targets. The method to make up for timeinduced loss in spatial localization ability exploits the local
behaviour of a coherence function, which correlates local observations to a set of spatially-stabilized reference stations. The
consequent normalization of measured magnetic signals allows one to assign the monitored areas with a specific level of
confidence in the detection results, ranging from 100% (certainty) to 0% (random events).
The principles of HD detection have been fully applied in the seafloor clearance of the firing test site located south of Cape
Teulada (Sardinia, Italy), where very weak signal sources such as cartridge cases, mines, and small objects down to 1 Kg mass
values (lobster pots) have been successfully localized, even when covered by extensive colonies of Posidonia.
Description:
Published
Description:
Stockolm, Sweden
Description:
1.6. Osservazioni di geomagnetismo
Description:
2.5. Laboratorio per lo sviluppo di sistemi di rilevamento sottomarini
Description:
3.4. Geomagnetismo
Description:
open
Keywords:
Seafloor clearance
;
magnetic survey
;
magnetic detection
;
proton Overhauser magnetometer
;
04. Solid Earth::04.02. Exploration geophysics::04.02.04. Magnetic and electrical methods
;
04. Solid Earth::04.02. Exploration geophysics::04.02.07. Instruments and techniques
;
04. Solid Earth::04.05. Geomagnetism::04.05.04. Magnetic anomalies
;
04. Solid Earth::04.05. Geomagnetism::04.05.08. Instruments and techniques
;
05. General::05.01. Computational geophysics::05.01.01. Data processing
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
Conference paper
Permalink
