View source for Hybrid navigation

{{short description|Simultaneous use of more than one navigation system type's elements for location data determination}}
'''Hybrid navigation''' is the simultaneous use of more than one [[navigation system]] for location data determination, needed for [[navigation]]. By using multiple systems at once, the accuracy as a whole is improved. It also allows for a more reliable navigation system, as if one system fails, the other can kick in and provide accurate navigation for the user. <ref>{{Cite book|last=Rizos, C, [[Dorota Grejner-Brzezińska|Grejner-Brzezinska, DA]], Toth, CK, Dempster, AG, Li, Y, Politi, N, Barnes, J, Sun, H|url=http://worldcat.org/oclc/1056492868|title=A hybrid system for navigation in GPS-challenged environments: case study|date=2008|publisher=Institute of Navigation (ION)|oclc=1056492868}}</ref> Especially for [[autonomous car|self-driving cars]], the exact and continuous knowledge of the navigating object's location is essential.<ref name=HNN1>{{cite web|url=http://www.golem.de/news/autonomes-fahren-wer-hat-die-besten-karten-1509-115506.html|title=AUTONOMES FAHREN: Wer hat die besten Karten?|editor=golem | author= Friedhelm Greis | date=2015-09-02 | language=de| accessdate=2016-07-17}}</ref>

== Function ==
<!-- need ref to support that GPS is the main/best/most-general one and others are only added to augment it -->
[[GPS]] and other [[satellite navigation|satellite based systems]] ([[GLONASS]], [[Galileo (satellite navigation)|GALILEO]], [[BeiDou Navigation Satellite System|BEIDOU]], [[Quasi-Zenith Satellite System|QZSS]]) provide a way to learn one's location, but these methods require [[free field]] conditions in order to receive the radio signal. Various satellite systems are subject to switching-off or reduction of data precision by the company or government that runs them.<ref name=AAHN1 /> They are also prone to intentional or unintentional disturbances. Even passing through a tunnel or a garage interrupts the data flow. In situations where the signal cannot be received reliably, alternate sources of location data are needed. Combining GPS with other methods can avoid these limitations, but each method has its own specific limitations. A hybrid system provides [[fault tolerance]] for each underlying method and improves the overall precision of the result.<ref>{{cite web | url=http://www.sanborn.com/highly-automated-driving-maps-for-autonomous-vehicles/| title=HIGHLY AUTOMATED DRIVING (HAD) MAPS FOR AUTONOMOUS VEHICLES| accessdate=2016-07-18}}</ref>

The hybrid system needs to decide how to choose among the different methods at any given time. One solution is a triple configuration, allowing 'result voting' for data collecting systems.<ref  name="AAHN1">{{cite web |url=http://www.insidegnss.com/node/2145 |title=Aviation Applications: Hybrid Navigation Techniques and Safety-of-Life Requirements |author=Bestmann, vonWulfen, Hecker, Kneissl, Kropp |date=August 2010 |accessdate=2016-07-17 |language=en |archive-url=https://web.archive.org/web/20160717125811/http://www.insidegnss.com/node/2145 |archive-date=2016-07-17 |url-status=dead }}</ref><ref name=ICON1>{{cite book|title=Multiple criteria decision making : proceedings of the Twelfth International Conference |editor1= Günter Fandel|editor2=Tomas Gal, Thomas Hanne |author=Johannes Jahn|chapter=Optimality Conditions in Set Valued Vector Optimation |pages=22 |location=New York |publisher= Springer-Verlag |date=1997}}</ref>

Alternate systems that supply navigational data include:
* [[Beacon]]s providing [[Radio beacon|radio-]] or [[TIRTL|infrared based]] signals.
* [[Inertial navigation system]]s. This system determines location by summing the movement vectors from start of the trip or some other [[waypoint]] whose location is well-defined.<ref>{{cite web|url=http://www.hydro-international.com/content/article/how-does-inertial-navigation-work |title=How Does Inertial Navigation Work? |editor= Hydro International|date= 2011-01-27 |author=Leendert Dorst | language=en|accessdate=2016-07-16}}</ref>
* Incremental sensors. This system uses vehicle speed data supplied by a [[Fleet Management System]].<ref>{{cite web|url=http://www.honeynav.com/etak/Etak%20paper%20RIN%20York%201985.pdf|title=NAV85 Papers|author=Stanley K. Honey|date=1985-04-02|language=en|accessdate=2016-07-17|url-status=dead|archiveurl=https://web.archive.org/web/20160304130717/http://www.honeynav.com/etak/Etak%20paper%20RIN%20York%201985.pdf|archivedate=2016-03-04}}</ref>
* [[Differential Global Positioning System|Differential GPS]]. This system uses [[terrestrial radio]] transmitters with well-defined locations that broadcast information about how accurate the GPS signals are at identifying the locations of these transmitters.<ref>{{cite web|url=http://www.southernavionics.com/blog/bid/43197/What-is-DGPS-or-Differential-GPS|title=What is DGPS or Differential GPS?|author= Brooks Goodhue | date= 2011-05-09 |language=en| accessdate=2016-07-16}}</ref>

== See also ==
* [[Automotive navigation system]]
* [[Hybrid positioning system]]
* [[Navigation Data Standard]]
* [[Sensor fusion]]

== References ==
<references/>

== External links ==
* [http://www.dgon.de Homepage of 'Deutschen Gesellschaft für Ortung und Navigation (DGON)']
* [http://www.th-wildau.de/sbruntha/Material/ON/TM13/Ortung%20und%20Navigation%20in%20der%20Luftfahrt2_ohne_video Wildau Video]

{{Commons category|Differential Global Positioning System}}
{{Commons category|Navigation}}

[[Category:Mobile technology]]
[[Category:Communication]]
[[Category:Navigational equipment]]