A Short His­tory of Nav­i­ga­tion

Business Traveler (USA) - - TECHNOLOGY OF THINGS -

In the Age of Dis­cov­ery of the 15th to 18th cen­turies, ex­plor­ers em­ployed lat­i­tude for north-south mea­sure­ments, tak­ing the equa­tor (0 de­grees) as its base point. With the an­gle mea­sured from the cen­ter of the Earth, plus 90 de­grees took you to the North Pole, and mi­nus 90 de­grees the South Pole. Lon­gi­tude, for east-west, was more com­pli­cated – as cen­turies of sea­far­ers will at­test. The 0 de­grees ref­er­ence point has been set at the Green­wich Merid­ian in Lon­don, with lon­gi­tude mea­sured as up to 180 de­grees east or mi­nus 180 de­grees west of this point.

As the Earth moves 360 de­grees a day, or 15 de­grees an hour, there is a di­rect re­la­tion­ship be­tween lon­gi­tude and time. If you are three hours ahead of UTC (Co­or­di­nated Uni­ver­sal Time, for­merly GMT), for ex­am­ple in Mo­gadishu, you will have a lon­gi­tude of 45 de­grees east. For this rea­son, hav­ing a re­li­able clock was es­sen­tial.

GPS co­or­di­nates rely on lat­i­tude and lon­gi­tude. The Em­pire State Build­ing has a lat­i­tude of north 40º 44’54.388”, while the lon­gi­tude is west 73º 59’8.39”. Global Satel­lite Po­si­tion­ing, how­ever, wasn’t de­vel­oped un­til the 1970s, when the US De­part­ment of De­fense took in­spi­ra­tion from the way ra­dio sig­nals were be­ing trans­mit­ted by Rus­sian satel­lite Sput­nik. When Korean Air flight 007 was shot down af­ter ac­ci­den­tally en­ter­ing Soviet airspace in 1983, the US govern­ment ex­tended the tech­nol­ogy to civil­ian air­lines, but it wasn’t un­til 2000 that it be­came avail­able to ev­ery­one.

GPS con­tin­ues to be owned by the US govern­ment. So far, just over 70 satel­lites have been put in Space although not all are in ser­vice – the min­i­mum num­ber re­quired for a“full con­stel­la­tion”is 24. While a few early at­tempts at pro­duc­ing in-car GPS and hand­held re­ceivers had en­tered the mar­ket in the nineties, it wasn’t un­til the early 2000s that the tech­nol­ogy be­came ac­cu­rate enough to be re­ally use­ful.

The first suc­cess­ful per­sonal nav­i­ga­tion de­vice (PND) was re­leased by Tom­Tom in 2004, with Garmin and Mag­el­lan quickly get­ting in on the act. By 2008, more than 18 mil­lion units had been sold in the US, but sales went into de­cline with the emer­gence of built-in GPS on smart­phones. Google Maps Nav­i­ga­tion with turn-by-turn di­rec­tions en­tered the scene in 2009, with Ap­ple Maps fol­low­ing in 2012.

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