Suitability of Low-Frequency Navigation Systems for Artillery Positioning in a GNSS Denied Environment

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.