^7fIn the last few years the development of smaller inertial sensors has been pushed forward. The dimensions of the newest sensors, which are partly still in pilot production measure a few millimetres only. The price of the sensors decreases in line with the size caused in the massive increasing production figures and the application of low cost micro mechanical silicon structures. This makes applications with low cost systems possible in the meantime. The Fraunhofer Technology Development Group (TEG) in Stuttgart has shown the possibility of motion-tracing an object with new low cost miniaturised sensors. The main drawback of low cost Inertial Navigation Systems (INS, Fig. 1) is the sensor drift, because decreasing volume and price goes hand in hand with a strong decrease in accuracy. This disadvantage has obviated the advantage of the low cost sensors up to now . To realise INS in spite of these boundary conditions innovative and complex algorithms are needed to compensate for the inaccuracies. In this case the calibration of the sensors is an important factor. First of all the research focus is on handling and analysing the recorded sensor signals. In this point the needed algorithms exceed the algebraical coherence. Complex algorithms from statistical signal processing and the theory of probabilities come into operation. Furthermore, the application-specific algorithms analyse the custom-designed environment to extract information to improve the accuracy of our orientation tracking . The motivation for developing INS for the Fraunhofer TEG is both the need of INS in hand-held-devices for engineering applications, and for low cost systems for the mass market. Marketable products like computer mice and electronic pens are only two of many applications of INS in the low cost segment.
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