| US 7,603,251 B1 | ||
| Magnetic anomaly sensing system for detection, localization and classification of a magnetic object in a cluttered field of magnetic anomalies | ||
| Roy Wiegert, Panama City, Fla. (US); and John Oeschger, Lynn Haven, Fla. (US) | ||
| Assigned to The United States of America as represented by the Secretary of the Navy, Washington, D.C. (US) | ||
| Filed on Jun. 23, 2008, as Appl. No. 12/214,803. | ||
| Int. Cl. G01V 3/00 (2006.01); G06F 19/00 (2006.01) | ||
| U.S. Cl. 702—152 | 18 Claims |
| 1. A magnetic anomaly sensing system, comprising:
at least eight triaxial magnetometer (TM) sensors with one of said TM sensors positioned at each vertex of a cubic space,
each of said TM sensors having X, Y, Z magnetic sensing axes, said TM sensors positioned such that respective ones of said
X, Y, Z magnetic sensing axes are mutually parallel to one another, each of said TM sensors measuring a local magnetic field
associated with a target region and generating magnetic field data indicative thereof;
processing means coupled to said TM sensors for
(a) processing said magnetic field data in accordance with a magnetic scalar triangulation and ranging (STAR) processing scheme
to determine a plurality of gradient contractions CT,I at a corresponding plurality of measurement points I to include at least at the center of each face of said cubic space wherein
gradient contraction pairs (CT,+X and CT,−X), (CT,+Y and CT,−Y) and (CT,+Z and CT,−Z) are defined for each of said X, Y, Z magnetic sensing axes along corresponding X, Y and Z baselines with each of said gradient
contraction pairs being symmetrically disposed about the center of said cubic space, and wherein said gradient contractions
from each of said gradient contraction pairs are separated by a corresponding baseline distance ΔSX, ΔSY and ΔSZ along one of said X, Y and Z baselines,
(b) determining a directional derivative ∇CT using said gradient contraction pairs and said baseline distances,
(c) calculating a unit vector using said directional derivative ∇CT,
(d) determining a projection distance from each of said measurement points toward the target region wherein each said projection
distance is a function of said unit vector and one of said baseline distances ΔSX, ΔSY and ΔSZ, and
(e) processing each said projection distance in accordance with said STAR processing scheme to determine first values of (i)
a position vector from the center of said cubic space to the target region, and (ii) a magnetic moment vector; and
output generation means coupled to said processing means for generating at least one of a human-discernable output and a computer-discernable
output of said first values.
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