Some years ago I worked on a project whose goal was the reconstruction of the path of a ship at sea based on a variety of navigational data. This was in the very early years of the Global Positioning System (GPS). We had speed and heading, some measurements from the LORAN radio frequency positioning system, and a handful of satellite fixes. I knew very little about navigation, but I learned a lot pretty quickly. Along the way I was directed to The American Practical Navigator, written by Nathaniel Bowditch and published in 1802. There have been many revised editions and the current one (freely available online here) even has an extensive section on GPS. I found the book marvelous; it kindled a lifelong interest in navigation and geodesy.
The current book is aimed at a broader audience than Bowditch. It could well elicit some of the same fascination with navigation and its history. It is an introduction to navigation for a popular audience that has few prerequisites. The author is a physicist who uses geometrical arguments and diagrams effectively, and entirely avoids algebra, trigonometry and anything that looks like an equation. His intention is to provide the reader with an understanding of the physical principles needed to appreciate navigation and how they came to be understood.
Navigation could be defined as the art of knowing where you are and how to get from where you are to where you want to go. At the core of the modern science of navigation are geodesy, cartography and remote sensing. The author begins there with discussions of the shape of the world, map making and surveying. As he tells how navigational tools and techniques evolved over time, he relates the history of the great explorers who drove their development.
During the electronic age — beginning during the Second World War — several new navigation tools emerged. The author devotes individual sections to several of these new systems: inertial navigation, radar, radio direction-finding systems, and satellite systems, especially GPS. The capabilities we have now with GPS would have seemed like pure magic to those early explorers.
Technically-inclined readers would probably wish for more details, but the author does a remarkable job of conveying the critical ideas with diagrams and some geometry. This is an excellent introduction to the ideas of navigation and it is accessible to anyone who’s had some basic geometry.
Bill Satzer (firstname.lastname@example.org) is a senior intellectual property scientist at 3M Company, having previously been a lab manager at 3M for composites and electromagnetic materials. His training is in dynamical systems and particularly celestial mechanics; his current interests are broadly in applied mathematics and the teaching of mathematics.