Predicting In-Flight MAD Noise from Ground Measurements

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Authors
  1. Nelson, J.B.
Corporate Authors
Defence Research Establishment Atlantic, Dartmouth NS (CAN)
Abstract
In the past, determing the magnetic state of magnetic anomaly detector (MAD)-equipped aircraft required dedicated flight time. It was necessary to perform standard pitch, roll, and possibly yaw maneuvers to measure the uncompensated Figure-of-Merit in order to determine if the aircraft's magnetic state had changed. This change could have been caused by ferrous material left in the vicinity of the magnetometer during an aircraft refit, replacement of the MAD sensor, or large-scale modifications to the aircraft or its systems. A new technique using only a few measurements taken on the ground at a magnetically quiet site (e.g. a Compass Rose) has been developed to monitor the magnetic sate of MAD-equipped aircraft. The technique, first suggested by CAE, was used to model th epermanent and induced magnetic sources on the National Research Council Convair 580 aircraft and to predict the in-flight MAD noise. Although the predicted noise amlitudes do not match the measured amplitudes for individual aircraft maneuvers, the standard deviations agree to within a few percent when calculated over a full set of compensation maneuvers. Thus the ground measurements can be used as an indicator of the degree of magnetic contamination in the aircraft. This technique could be adapted to monitor the magnetic characteristics of both the Canadian forces CP-140 and CH-124B fleet, and to conduct a number of MAD-related experiments at a minimal cost.

Il y a un résumé en français ici.

Keywords
Magnetic signatures;Helicopters (CH-124);Noise compensation;Permanent magnetic sources;Induced magnetic sources;AN/SQS-504
Report Number
DREA-TM-2001-112 — Technical Memorandum
Date of publication
01 Apr 2002
Number of Pages
26
DSTKIM No
CA021689
CANDIS No
518407
Format(s):
CD ROM

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