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Title: Adaptive methods for motion-noise compensation in extremely low frequency submarine receiving antennas

Abstract

Motion-induced noise can be an overwhelming source of interference in vector magnetic field sensors designed for submarine communications in the 30-130-Hz portion of the extremely low frequency (ELF) band. In the case of an ELF antenna constructed using three orthogonal superconducting quantum interference devices (SQUID's) as receiving elements, the removal of motion noise is complicated by the inability of SQUID sensors to determine the absolute value of the earth's field component along the axis of the sensor. An equation is derived that expresses the projection of the ELF signal vector on the earth's field in terms of the SQUID outputs, and an adaptive vector that is approximately equal to the earth's field vector. Two adaptive schemes using the methods of process parameter estimation are described which determine the adaptive vector. The Least Squares method requires no initial estimate of the adaptive vector but is an open-loop method which tends to be slow. The second adaptive scheme, the steepest descent method, is a closed-loop technique that has the potential of being rapid, but requires an initial value of the adaptive vector that is close to the true value. Both techniques remove, to first order, sources of noise arising from sensor nonorthogonality,more » sensitivity differences, and dc offset errors. From a computer simulation of both techniques, it is found that the optimum system is a combination of the two methods, using the Least Squares method for estimation of the coarse value of the adaptive vector, and using the Steepest Descent method for fine adjustment.« less

Authors:
;
Publication Date:
Research Org.:
Naval Research Lab., Washington, DC
OSTI Identifier:
7215612
Resource Type:
Journal Article
Journal Name:
Proc. IEEE; (United States)
Additional Journal Information:
Journal Volume: 64:10
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; SQUID DEVICES; USES; SUBMARINES; COMMUNICATIONS; HZ RANGE; MAGNETIC FIELDS; MOTION; NOISE; ELECTRONIC EQUIPMENT; FLUXMETERS; FREQUENCY RANGE; MEASURING INSTRUMENTS; MICROWAVE EQUIPMENT; SHIPS; SUPERCONDUCTING DEVICES; 420201* - Engineering- Cryogenic Equipment & Devices

Citation Formats

Dinger, R J, and Davis, J R. Adaptive methods for motion-noise compensation in extremely low frequency submarine receiving antennas. United States: N. p., 1976. Web. doi:10.1109/PROC.1976.10366.
Dinger, R J, & Davis, J R. Adaptive methods for motion-noise compensation in extremely low frequency submarine receiving antennas. United States. https://doi.org/10.1109/PROC.1976.10366
Dinger, R J, and Davis, J R. 1976. "Adaptive methods for motion-noise compensation in extremely low frequency submarine receiving antennas". United States. https://doi.org/10.1109/PROC.1976.10366.
@article{osti_7215612,
title = {Adaptive methods for motion-noise compensation in extremely low frequency submarine receiving antennas},
author = {Dinger, R J and Davis, J R},
abstractNote = {Motion-induced noise can be an overwhelming source of interference in vector magnetic field sensors designed for submarine communications in the 30-130-Hz portion of the extremely low frequency (ELF) band. In the case of an ELF antenna constructed using three orthogonal superconducting quantum interference devices (SQUID's) as receiving elements, the removal of motion noise is complicated by the inability of SQUID sensors to determine the absolute value of the earth's field component along the axis of the sensor. An equation is derived that expresses the projection of the ELF signal vector on the earth's field in terms of the SQUID outputs, and an adaptive vector that is approximately equal to the earth's field vector. Two adaptive schemes using the methods of process parameter estimation are described which determine the adaptive vector. The Least Squares method requires no initial estimate of the adaptive vector but is an open-loop method which tends to be slow. The second adaptive scheme, the steepest descent method, is a closed-loop technique that has the potential of being rapid, but requires an initial value of the adaptive vector that is close to the true value. Both techniques remove, to first order, sources of noise arising from sensor nonorthogonality, sensitivity differences, and dc offset errors. From a computer simulation of both techniques, it is found that the optimum system is a combination of the two methods, using the Least Squares method for estimation of the coarse value of the adaptive vector, and using the Steepest Descent method for fine adjustment.},
doi = {10.1109/PROC.1976.10366},
url = {https://www.osti.gov/biblio/7215612}, journal = {Proc. IEEE; (United States)},
number = ,
volume = 64:10,
place = {United States},
year = {Fri Oct 01 00:00:00 EDT 1976},
month = {Fri Oct 01 00:00:00 EDT 1976}
}