Integrated micro-electro-mechanical sensor development for inertialapplications

Electronic sensing circuitry and micro-electro-mechanical sense elements can be integrated to produce inertial instruments for applications unheard of a few years ago. This paper describes the Sandia M³EMS fabrication process, inertial instruments that have been fabricated, and the results of initial characterization tests of micro-machined accelerometers     

Moving Europe towards a more effective procurement of space-based assets

It has become essential for European states to consider a more coherent strategy in the procurement of future space assets in order to safeguard European industrial competitiveness. Space-related research programmes remain uncoordinated and separated between civil, military and commercial applications. This paper explores the present European institutional environment and the interaction between different actors involved in space procurement. New developments are underway with the establishment of the European Defence Agency and the attempt to federate existing groups and actions. Institutional users of space systems, including defence customers, often rely on the same technology. The article considers space procurement from a widespread perspective, which goes beyond sectoral boundaries. The establishment of a permanent advisory forum is suggested in order to centralise various requirements at European level and procure space assets more efficiently.     

Using GPS to calibrate Loran-C

Various techniques for using simultaneous Global Positioning System (GPS)/Loran data to estimate the propagation uncertainties that limit the absolute accuracy of Loran-C are discussed. Significant improvements in the absolute accuracy of Loran can be achieved with very simple calibrations. The absolute accuracy of Loran in the Gulf of Maine without calibration is presented. The maximum and RMS absolute errors are between 700 and 500 m, depending on the choice of land model. Simple calibrations greatly improve the absolute accuracy of Loran. As shown, if the land conductivities are fixed a priori and a single parameter is optimized, the maximum and RMS absolute errors fall to around 250 and 60 m, respectively. Alternatively, land can be treated as a single conductivity which can be adjusted to reduce offshore additional secondary phase factor errors. The performance of this practice is summarized in tables which show maximum and RMS errors of around 300 to 100 m, respectively