# A mathematical model of extremely low frequency ocean induced electromagnetic noise

## Abstract

Magnetic Anomaly Detection (MAD) system uses the principle that ferromagnetic objects disturb the magnetic lines of force of the earth. These lines of force are able to pass through both water and air in similar manners. A MAD system, usually mounted on an aerial vehicle, is thus often employed to confirm the detection and accomplish localization of large ferromagnetic objects submerged in a sea-water environment. However, the total magnetic signal encountered by a MAD system includes contributions from a myriad of low to Extremely Low Frequency (ELF) sources. The goal of the MAD system is to detect small anomaly signals in the midst of these low-frequency interfering signals. Both the Range of Detection (R{sub d}) and the Probability of Detection (P{sub d}) are limited by the ratio of anomaly signal strength to the interfering magnetic noise. In this paper, we report a generic mathematical model to estimate the signal-to-noise ratio or SNR. Since time-variant electro-magnetic signals are affected by conduction losses due to sea-water conductivity and the presence of air-water interface, we employ the general formulation of dipole induced electromagnetic field propagation in stratified media [1]. As a first step we employ a volumetric distribution of isolated elementary magnetic dipoles,more »

- Authors:

- Research & Development Engineer, Anyeshan Limited, Dhaka (Bangladesh)

- Publication Date:

- OSTI Identifier:
- 22608570

- Resource Type:
- Journal Article

- Journal Name:
- AIP Conference Proceedings

- Additional Journal Information:
- Journal Volume: 1754; Journal Issue: 1; Conference: ICME 2015: 11. international conference on mechanical engineering, Dhaka (Bangladesh), 18-20 Dec 2015; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-243X

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; DETECTION; DISTRIBUTION; ELECTROMAGNETIC FIELDS; INTERFACES; LOSSES; MAGNETIC DIPOLES; MATHEMATICAL MODELS; NOISE; PROBABILITY; SIGNALS; SIGNAL-TO-NOISE RATIO; SIMULATION

### Citation Formats

```
Dautta, Manik, E-mail: manik.dautta@anyeshan.com, Faruque, Rumana Binte, E-mail: rumana.faruque@anyeshan.com, and Islam, Rakibul, E-mail: rakibul.islam@anyeshan.com.
```*A mathematical model of extremely low frequency ocean induced electromagnetic noise*. United States: N. p., 2016.
Web. doi:10.1063/1.4958451.

```
Dautta, Manik, E-mail: manik.dautta@anyeshan.com, Faruque, Rumana Binte, E-mail: rumana.faruque@anyeshan.com, & Islam, Rakibul, E-mail: rakibul.islam@anyeshan.com.
```*A mathematical model of extremely low frequency ocean induced electromagnetic noise*. United States. doi:10.1063/1.4958451.

```
Dautta, Manik, E-mail: manik.dautta@anyeshan.com, Faruque, Rumana Binte, E-mail: rumana.faruque@anyeshan.com, and Islam, Rakibul, E-mail: rakibul.islam@anyeshan.com. Tue .
"A mathematical model of extremely low frequency ocean induced electromagnetic noise". United States. doi:10.1063/1.4958451.
```

```
@article{osti_22608570,
```

title = {A mathematical model of extremely low frequency ocean induced electromagnetic noise},

author = {Dautta, Manik, E-mail: manik.dautta@anyeshan.com and Faruque, Rumana Binte, E-mail: rumana.faruque@anyeshan.com and Islam, Rakibul, E-mail: rakibul.islam@anyeshan.com},

abstractNote = {Magnetic Anomaly Detection (MAD) system uses the principle that ferromagnetic objects disturb the magnetic lines of force of the earth. These lines of force are able to pass through both water and air in similar manners. A MAD system, usually mounted on an aerial vehicle, is thus often employed to confirm the detection and accomplish localization of large ferromagnetic objects submerged in a sea-water environment. However, the total magnetic signal encountered by a MAD system includes contributions from a myriad of low to Extremely Low Frequency (ELF) sources. The goal of the MAD system is to detect small anomaly signals in the midst of these low-frequency interfering signals. Both the Range of Detection (R{sub d}) and the Probability of Detection (P{sub d}) are limited by the ratio of anomaly signal strength to the interfering magnetic noise. In this paper, we report a generic mathematical model to estimate the signal-to-noise ratio or SNR. Since time-variant electro-magnetic signals are affected by conduction losses due to sea-water conductivity and the presence of air-water interface, we employ the general formulation of dipole induced electromagnetic field propagation in stratified media [1]. As a first step we employ a volumetric distribution of isolated elementary magnetic dipoles, each having its own dipole strength and orientation, to estimate the magnetic noise observed by a MAD system. Numerical results are presented for a few realizations out of an ensemble of possible realizations of elementary dipole source distributions.},

doi = {10.1063/1.4958451},

journal = {AIP Conference Proceedings},

issn = {0094-243X},

number = 1,

volume = 1754,

place = {United States},

year = {2016},

month = {7}

}