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In an environment where Global Positioning System (GPS) jamming is present, the Dutch army faces all sorts of challenges in such a deployment area, e.g., for the determination of gun locations. Nowadays, an Inertial Navigation System (INS) is used as back-up positioning system. However, to use this back-up tool within specified accuracy limits, additional procedures are needed that limit deployment. An alternative positioning method such as a low-frequency navigation system could be a solution to these problems. An example of a low-frequency navigation system that is currently operational in certain regions is eLORAN (enhanced LOng RAnge Navigation). Hypothetically, a system like this could be realised in a similar way for positioning, navigation and timing solutions for large scale military operations. That is if the performance of eLORAN meets the accuracy requirements. In this paper, eLORAN performances are examined using experiments conducted at a military heath land area in the Netherlands. Moreover, eLORAN Additional Secondary Factor (ASF) correction maps have been computed for that particular area, based on differences in position between Real-Time Kinematic (RTK) GPS and eLORAN measurements at a fixed number of points in that area. Different interpolation methods are used to create these ASF maps. The maps, obtained from static measurements, are used to enhance eLORAN's performance in dynamic measurements using a military platform. The content of this paper has been presented during the European Navigation Conference 2011 in London.

We propose to use adaptive wavelet lifting for image retrieval systems that are based on shape detection and multiresolution structures of objects in a database against a background of texture. To measure the performance of our approach, feature vectors are computed based on moment invariants of detail coe cients produced by the adaptive lifting scheme and retrieval rates are obtained by measuring distances between these vectors. Retrieval rates are compared with the rates obtained when using non-adaptive wavelet ÿltering as a preprocessing step. A synthetic database is created for this simulation.