Integrated navigation

Integrated navigation is beyond the art of steering the optimal combination of the individual navigation methods . This means that modern location determination and control of land, water and air vehicles gains both accuracy and reliability.

Weighted combination of measurement data

If navigation - in short - is the control of a vehicle to the selected destination , then the integrated (or hybrid ) navigation combines several navigation methods and weights them according to accuracy and reliability . Conversely, the optimally calculated (“most probable”) position then allows statements to be made as to whether the selected data and control model was the best.

Since the 1980s, navigation systems have developed into automated methods of determining position in the areas of seafaring , aviation , road traffic and land surveying ( geodesy ).

The "vehicle" type ship and aircraft these developments are being pushed on raschesten, but also play for Geodatenerfasser, large agricultural machinery and trucks - vehicle fleets involved. The navigation of private cars combines fewer individual elements, as the digital map is an important data source .

The most important data sources

The individual types of navigation that it makes sense to include in a hybrid model are:

• The dead reckoning - ongoing location determination from course and speed. The wind is taken into account by calculating the drift ; Doppler radar and other additional data increase the accuracy.
• The inertial navigation - autonomous navigation by using accelerometers and gyroscopes .
• In radio navigation , transmitting stations are used that send out radio signals to determine position. Of the dozen procedures, the most important are:
  • Bearing (radio compass, ADR ), directional transmission ( VOR and TACAN, Consol and derivatives),
  • and the hyperbolic methods Decca and LORAN C (until ~ 2000 also the global omega ).
• In satellite navigation (see also GPS and Galileo ) signals from satellites are used; their transit times to the recipient "cut" its position out of the globe.
• The celestial navigation - the location by observing heavenly bodies (sun, stars and planets) - is currently only in the space an important data source. In flight and terrestrially , it has lost its importance for about 10 years due to GPS. In the future, however, it can contribute to hybrid navigation again when new sensors replace the eye .

Other methods are also important for pilots and navigators , but more for their sense of space than for pure localization. They include:

• the sense of balance and muscles ,
• the visual navigation - comparison of map and terrain and unconscious construction of a "mental model",
• the terrestrial navigation - positioning near the coast based on landmarks (prominent landmarks on land and sea mark ).

Some of these methods are difficult to model mathematically, although research has long been carried out on replicating human "built-in systems".

Special developments

The Stuttgart Institute for Navigation, which was founded in the 1960s by Karl Ramsayer , carries out special developments . From the earlier “automatic coupling cards”, a research direction has emerged that uses digital filtering methods (e.g. Kalman filters ) to determine typical sensor errors and thus more precise positions . In this context, the term "estimation" is usually used. This may surprise the layman when it comes to accuracy down to a few centimeters and meters. But the word comes from technical statistics , where nothing is considered completely error-free .

See also

• Nautical , aviation , aerospace , shipping
• Regression analysis , collocation , optimization , Gissen
• Coordinate system , radio technology , GPS , Galileo , GLONASS , Vertigo

Web links

• Institute for Navigation, University of Stuttgart

literature

Non-fiction books on the development of navigation

• HC Free Life: History of Navigation . F. Steiner Verlag, Wiesbaden 1978, ISBN 3-515-02370-4 .
• G. Hilscher: Flight without stars. Siegfried Reisch - pioneer of inertial navigation . 1992, ISBN 3-907175-21-2 .

Non-fiction books on the current status of integrated navigation systems

• JF Wagner: On the generalization of integrated navigation systems to spatially distributed sensors and flexible vehicle structures. (= Progress reports VDI. Series 8, No. 1008). VDI Verlag, Düsseldorf 2003, ISBN 3-18-500808-1 .

• S. Winkler: For sensor data fusion for integrated navigation systems of unmanned microplanes. Shaker Verlag , Aachen 2007, ISBN 978-3-8322-6060-6 .