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N VIG TION L LGORITHMS

CCeelleesstt iiaall NNaavviiggaatt iioonnEExxaammppllee

Andrs RuizSan Sebastin Donostia

43 19N 002W

http://sites.google.com/site/navigationalalgorithms/

http://sites.google.com/site/navigationalalgorithms/http://sites.google.com/site/navigationalalgorithms/

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Celestial Navigation Example 2

Navigational Algorithms http://sites.google.com/site/navigationalalgorithms/

The following example is from the book: NavPac and Compact Data 2001-2005. ISBN011887311 3. C.Y. Hohenkerk and B.D. Yallop , Her Majesty's Nautical Almanac Office. TheStationery Office.

And the software is freely available at the Navigational AlgorithmsWeb site.

The Running Fix problem is easily solved using CelestialFix.exe

Introduce de data for the four observations:

Date

Time UT1 of the observation

Name of the body

Declination

Greenwich Hour Angle

Observed altitude

and the data of time of fix and course R andspeed V between the observations.

The estimated position is needed as an initialposition for the iterative solution process, if isvery rough the required number of iterations isgreater.

Parameters of a circle of position in astronavigation

The Do pushbutton gives the solution shown in figure 1.

The Coastlines WVS pushbutton plots the circles of equal altitude on a Mercator chart based in

the World Vector Shoreline. Figure 2.

The GPX pushbutton generates a gpx file with the circles of position associates to each

observation, the Fix and the Confidence Ellipse. This GPX file serves as an input to OpenCPNfigures 3,4, and Google Earth figure 5. For this example the file is cd20012005.gpx

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Celestial Navigation Example 3

Fig 1. Solution with CelestialFix.exe

Navigational Algorithms http://sites.google.com/site/navigationalalgorithms/

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Celestial Navigation Example 4

Fig 2. Circles of position or Circles of equal altitude.

Chart Work.exegenerates a GPX for an observation. It is useful for simultaneous sights.

Navigational Algorithms http://sites.google.com/site/navigationalalgorithms/

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Celestial Navigation Example 5

Fig 3. GPX file in OpenCPN. Circles of equal altitude. General scale.

Fig 4. GPX file in OpenCPN. Fix and confidence ellipse. Coastal scale.

Navigational Algorithms http://sites.google.com/site/navigationalalgorithms/

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Celestial Navigation Example 6

Fig 5. GPX file in Google Earth. Circles of equal altitude.

References

GPX http://www.topografix.com/gpx.asp

OpenCPN is a free software (GPL) project to create a concise chart plotter andnavigation software for use as an underway or planning tool. http://www.opencpn.org/

Google Earth http://earth.google.com/

Navigational Algorithms http://sites.google.com/site/navigationalalgorithms/

http://www.opencpn.org/http://www.opencpn.org/