Mark Denny

I'm a science writer, and my books explain how things work.

. (9) The Science of Navigation: From dead reckoning to GPS

In this book we see how mariners and explorers over the ages have learned to navigate across the globe, with tools that evolved from dead reckoning to GPS. Mapmaking (cartography), geodesics, and surveying are all part of the story. Plus, I couldn't resist adding some of the more inspiring explorations from history: the Phoenicians who circumnavigated Africa, the Ancient Greek who sailed into Arctic waters, etc. I am aiming, as always, for a good explanation that avoids as much of the technicalities as possible (without losing the essential physics). Happily, in this case the subject (being essentially geometrical) is easy to convey with figures and diagrams.


"I was a professional navigator for a good number of years, and I find Denny's explanations to be extraordinarily clear and accurate. In many cases they're delightfully so. For any intelligent reader, the book is about the science behind the marvelous arts once used for millennia to answer two of life's important questions: 'Where am I?' and 'How do I get to where I'm going?'" William Withuhn, Curator Emeritus, Smithsonian Institution

"I’ve just finished your book The Science of Navigation. Loved it. Thanks for writing such an excellent book – I am placing it on my course’s recommended reading list." Hilary Sandford, Camosun College 2013-01-00 


A GPS satellite. Twenty four of these are placed in geostationary orbit so that signals from at least four of them can be received simultaneously at any point on earth. processing these timing signals provides accurate positioning information within a few seconds. The satellite transmitters are provided free by the US military; the receivers cost a few hundred dollars. GPS is the pinnacle of hi-tech navigation.


Earlier navigation also relied on timing. This is the hi-tech solution of the late eighteenth century: John Harrison's H5 marine chronometer, which enabled fairly accurate estimates of longitude to be made, for the first time.