Tag Archives: GPS failure

Accuracy of Sight Reduction Methods.

Posted on June 30, 2018 by Jack Case

In my recent article ‘Why Astro‘, I highlighted the risks in using the GPS.  Since writing that article, I am frequently asked “if astro / celestial navigation is to be used, which of the many systems is the best”.  Sight … Continue reading →

Posted in astro navigation, celestial navigation, global positioning system, gps, Marine Navigation, mathematics, navigation, spherical trigonometry, trigonometry | Tagged , , , , | Leave a comment

In Defence of Mer Pas

Posted on March 27, 2018 by Jack Case

The noon sight for latitude is a method of calculating latitude from the altitude of the sun at the instant it crosses your meridian and for this reason, the method is also known as ‘Meridian Passage’ or ‘Mer. Pas’.  I … Continue reading →

Posted in astro navigation, astronomy, celestial navigation, gps, navigation | Tagged , , , | Leave a comment

Why Astro?

Posted on January 6, 2018 by Jack Case

In a recent article the discussion centred on our over-reliance on GPS for navigation at sea and the need for back-up systems.  The conclusion drawn was that we already have a back-up system, one that has been tried and tested … Continue reading →

Posted in astro navigation, celestial navigation, electronic navigation systems, global positioning system, gps, Marine Navigation, navigation | Tagged , , , | Leave a comment

What’s The Point of Astro Navigation When We Have The GPS?

Posted on September 16, 2017 by Jack Case

Imagine that you are driving through Birmingham when, suddenly, your ‘Sat Nav’ starts to tell you that you are in Manchester.  In such a situation, you would quickly realise that the GPS had gone haywire; however, if you were in … Continue reading →

Posted in astro navigation, Astro Navigation Topics, astronomy, celestial navigation, coronal mass ejections, electronic navigation systems, gps | Tagged , , , , | Leave a comment

Astro Navigation – What is it and why do we need it?

Posted on January 8, 2012 by Jack Case

Astro-navigation (or celestial navigation as it is also known) is a fascinating subject that encompasses many areas of knowledge including geography, astronomy, history and mathematics.  As you unravel the principles and techniques upon which navigation is based, you will be … Continue reading →

Posted in Astro Navigation Topics, Schools | Tagged , , , , , , , , , , , , , | 1 Comment

Could the Global Positioning System Fail?

Posted on January 8, 2012 by Jack Case

Quite apart from the local risks of defective equipment, battery failure, generator failure and short-circuits to electronic navigation equipment caused by flooding, there is a very real global risk that the GPS could be destroyed. During periods of increased solar … Continue reading →

Posted in Astro Navigation Topics | Tagged , , , , , | 4 Comments