Casio's Global Positioning System in a watch
By Mike Hanlon
June 4, 2004
It reads out your current lattitude and longitude to within a few metres after conferring with between three and twelve satellites - the Casio Pro Trek is a truly incredible piece of machinery - a genuine monument to miniaturisation and applied technology. And it just happens to be the most accurate wrist-worn timepeice you can buy!!!!!!
The Global Positioning System (GPS) is a system of 24 satellites developed by the US Air Force and first made available for civilian use in 1990. If you have a GPS receiver, it can determine your location and altitude anywhere on the globe, within 15 metres, by reading information from three or more of these satellites circulating 18,000 kilometres above us. In order for a GPS receiver to determine your location, it must acquire the signal from a satellite, then measure the time between when the signal was transmitted and when it was received so it can work out its distance from the satellite. Once it has triangulated its position against three satellites, it knows where it is. Of course, there's MUCH more to it than that. The GPS watch tracks up to twelve satellites at the same time using twelve parallel receivers or channels, and it must know where to look in the sky for the satellites, and so on.
Anyway, the foremost fact about the Casio watch, the one the copywriters missed, is that by virtue of what it is, it has to be synchronised with the clocks of the satellites, which are in turn synchronised with an atomic clock accurate to within a billionth of a second. So the first thing to recognise when you look down and read your current latitude and longitude on the Casio Pro Trek is that it is an incredible piece of machinery - a genuine monument to miniaturisation and applied technology on a scale which is so vast it is hard to wrap one's brain cells around it. The satellite network which allows this watch to work is immense and cost billions to create.Oh, and thanks to its ability to synchronise via the satellites with the atomic clock, it is probably the most accurate wrist-worn timepiece available.But it's the watch's ability to tell you exactly where you are, where you have been and how to get back that makes it so useful. We sell more four-wheel drive vehicles and more trail bikes per head of population than any other nation and we have more accessible wilderness area available to us than any other country.
The Casio ProTrek can greatly enhance our access to the bush, our enjoyment and navigation within the bush, and our ability to return safely. Due to its screen size, it has many limitations compared to a handheld, purpose-built GPS, but being secured to a wrist, you will probably never see it fall into Sydney Harbour either. Should it ever go underwater for a moment on the end of your arm, it's no problem. The watch is water-resistant to 50 metres, thanks to the additional sealing made possible by having an externally rechargeable lithium-ion battery. The watch is also more than hardy enough to stand up to the moisture encountered during outdoor wear.Perhaps the most interesting and useful capability of this second-generation GPS watch is that it can be linked to a PC and comes bundled with software that enables quite versatile GPS data management capabilities.
You can use the PC link software to import and display map images (BMP or JPEG) on your PC, then use the map images to edit and define your waypoints and destination. You can also plot track points recorded by the watch on a map and keep records of your movements on your computer's hard disk.This offers a range of interesting and useful new capabilities. You could, for example, plot your starting point, waypoints, and final destination on a map on your computer screen, then transfer your route plan to the watch for the journey. Or you could make a journey, plotting your waypoints, then overlay it onto a map and email a ready-made route plan to a friend or club, so they could experience your recent bushwalk/trail ride.The Casio ProTrek is an incredible piece of machinery. In the time we had it, it never failed to impress with its robustness. It does everything Casio claims. It costs $895.