Kate and Eilidh do science...

Project number 5, 7 steps to enlightenment, 2 partners, 10 days, 1 question...

How does a Sat Nav work??

 And so Kate and Eilidh set out on a journey to find the answer to this intriguing question...

 'That's easy' I hear you cry! 'A little man named Tom Tom lives in the little box on your dashboard and uses magic maps and his powers of navigation to guide you safely to your destination!'
Not quite.
It's actually rather clever, and interesting! In order to find out how Sat Nav works, we need to find out, not only how a Satellite Navigation Receiver works, but also how GPS (Global Positioning System) works, and therefore, how GPS satellites work! It's all very sciency and techy, and luckily, I am a wannabe science geek, so find it all fascinating. This project has allowed me to indulge my love of art (we must illustrate our findings in 7 easy steps) and science! Cool beanz!

And here's the science bit! The answer involves 'Ephemeris data', 'Almanac data' and 'Pseudo Random Code.' In the most basic terms, the receiver is activated when it picks up the signal from 4 satellites (of which there are 24 orbiting the Earth, each emitting a continual signal, unique to each satellite.) The Satellites 'triangulate' or to use the correct terminology, 'trilaterate' the receiver's location, taking into account latitudal and longitudal co-ordinates, and attain accuracy due to their on-board, synchronised atomic clocks. On activation, the receiver selects the relevant map from it's software, and the hardware utilises previously installed settings to communicate the information to you, the driver, via a computer screen and audio instructions!!! And voila! Fanny's your Aunt and Robert's your Mother's Brother!!

Capiche?