Table of contents
4.Specification requirements
5.Solutions suggestions
6.The magnetic fields sensors
7.The inclination measurement system
8.The gyroscope
9.The data acquisition system
10.Communication system
11.The power supply
12.Realisation of the PCB
13.The embedded system
14.Static Library Util.a
17.Sensors controller commands
19.Future improvements

20.           Conclusion

The design and the implementation of an electromagnetic compass are described in this notes. The requirements have been almost respected and the Smart Compass can evaluate the azimuth with 1º accuracy in normal conditions and 2.5º in extreme conditions (for example an high tilt). We adapted the compass both to the MMR and the SMR environment. Indoor, we have often more interference magnetic field generated by the computer (interference detection) than outdoor but then the ground is bumpy (tilt compensation).

Corrections of systematic errors such alignment errors, non-linearity, and sensitivity deviations can lead to significant improvements in the overall system performance. With the aid of adequate feedback mechanisms (g-vector, GPS position) and signal processing algorithms (average building, Kalman filtering) further improvements in precision can be achieved.

The graphical interface offers an easy way to use the device from a computer but the main driver has been implemented on an independent library. A third program viewport have been developed to debug the card. The driver to manage the sensors could be easily installed on the MMR. Nevertheless, work has to be done to realize the main application of the MMR with this device.

A driver able to manage all this positioning system will be required, in particular to develop a correction’s program of systematic errors. And, in preparation of this work, a study of the different cases that could drive different results between these systems will be useful. The knowledge of the errors’ reason will bring an aid to design the programs, to know which device is more accurate in the several cases, and how to correct and improve the end position from all the results.

The final result of the navigation’s system is an accurate compass in diverse conditions, low cost and easy to use.

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