Air-Underwater Magnetic Communication Link
Distributed underwater sensor networks are an important part of sea monitoring systems. These networks usually include either moored or seabed sensors and Autonomous Underwater Vehicles (AUVs). In many applications it is desirable to establish communication between operation centres onshore or in mother-ships to AUV and underwater sensors. Acoustic channels become unreliable at large distances because of reflections near sea bed and increased noise at the surf zone. Use of Unmanned Aerial Vehicles (UAV) as an element of communication channel permits bringing the transmitter/receiver closer to the operational area.
Magnetic induction (MI) is a promising technique that is not affected by multipath propagation and fading. Magnetic communication link with frequencies in the ultra-low-frequency (ULF) band features good penetration ability even through salted sea water. ULF signals with frequencies in the range of 0.3 – 3 kHz feature skin effect depth values of about 4 – 13 m for sea water, and data rates range from several to hundreds bits per second. Thus, the ULF band seems as a reasonable tradeoff between penetration ability and data rate.
Magnetic communication is based on the magnetic coupling between a transmitting coil antenna and a receiver - search-coil magnetometer.
We investigate 1) downlink enabling to send commands and data from UAV to an AUV and underwater sensors performing an in situ undersea monitoring; 2) underwater-to-air communication up-link. The airborne transmitter comprises an air core coil excited by a low frequency alternating current which is modulated according to the transmitted binary data. The underwater receiver is based on a search-coil magnetometer which detects the received signal and demodulates the data.
The present work includes analysis of the communication link. Simulation of the low frequency magnetic field produced by magnetic moment and its interaction with the conductive media is performed. Some engineering aspects of receiver/transmitter installation are considered. We also estimate the link’s budget, considering receiver sensitivity, transmitter magnetic moment, and channel attenuation. The attenuation is calculated using a computer model including seabed-water and air-water interfaces.
Date and Time
Location
Hosts
Registration
-
Add Event to Calendar
- Macquarie University
- Sydney, New South Wales
- Australia 2109
- Building: E6B 149
- Contact Event Host
- Co-sponsored by Prof. Subhas Mukhopadhyay
Speakers
Boris Ginzburg
Biography:
Dr. Boris Ginzburg is a research physicist with the Soreq Nuclear Research Center. He earned his M.Sc. in radio-physics & electronics from the Technical University of St.-Petersburg (Russia). He obtained his Ph.D. in physics & mathematics from Phys.-Techn. Ioffe Institute, St.-Petersburg (Russia).
In the years 1974-1996 he served as research scientist at Geophysical Research Institute in St.-Petersburg.
From 1997 he was with the Geological Survey of Israel (GSI) where he was involved in investigation of tectonomagnetic effects.
From 2000 he is with Soreq NRC and takes part in projects related to precise magnetic measurements.
Dr. Ginzburg is the Head of research group; his main scientific interests are in the field of precise measurements of the Earth’s magnetic field and various magnetic search & detection applications.