In this paper, some improvements in feature extraction for geomagnetic
matching are made. Geomagnetic entropy is extracted from the total intensity
of the geomagnetic field and its performance for navigation is tested with
real geomagnetic data. The matching progress is divided into two phrases:
rough matching and precise matching. In the rough matching phase, a
sub-region that includes the real position is obtained by using the total
intensity of the geomagnetic field as the matching feature. The entropy is
applied to precise matching in the sub-region to obtain the final result.
Simulations show that the navigation effect is significantly improved with
the entropy as an assistant feature. The combined match probability is much
better than the results derived from those using only total intensity as
the matching feature. This is especially true when the flight vehicle passes
through an area without abundant magnetic information.
keywords: feature extraction, geomagnetic navigation, geomagnetic matching, entropyJournal of Navigation 66, 799-811 (2013)