Aeromagnetic Noise During Low-Altitude Flights Over the Scotian Shelf

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Authors
  1. Nelson, J.B.
Corporate Authors
Defence R&D Canada - Atlantic, Dartmouth NS (CAN)
Abstract
A low-altitude flight was conducted with the National Research Council Convair 580 aeromagnetic research aircraft over the Scotian Shelf. The data were filtered to first accentuate the MAD frequencies (0-1 Hz), then the ELF frequencies (1-16 Hz). Two adaptive compensation algorithms have been developed to remove aircraft-generated noise in the two frequency bands. Residual noise in the ELF band is very close to the sensor noise level. By adding simulated ELF target signatures into the airborne data, it has been shown that the algorithm will remove the aircraft-generated noise but has little effect on the ELF signature. The residual noise in the MAD frequency band shows an altitude and heading dependence. Various mechanisms for this excess noise have been investigated including, turbulence, geology, and geomagnetic activity. None were found capable of reproducing the memeasured noise. However, noise from wind-driven waves, as simulated from the data collected at nearby wavebuoys, does roughly reproduce the heading and altitude effects seen. Further trials with larger sea states are required to determine if the wave/swell noise can be accurately modeled and removed from the airborne data.

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Keywords
Scotian Shelf;Aeromagnetic surveys;Filtering;Aircraft generated noise;Aircraft self-noise
Report Number
DRDC-ATLANTIC-TM-2002-089 — Technical Memorandum
Date of publication
01 May 2002
Number of Pages
40
DSTKIM No
CA021659
CANDIS No
518377
Format(s):
CD ROM

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