My fascination with global positioning devices has not abated but it seems that not everyone shares my naive enthusiasm.

Devoted readers of this blog will recall my childlike sense of wonder at renting a car in Los Angeles last year and being guided around the city with a GPS device. Of course, GPS was already old hat then for many car drivers, but there we are.

My latest experiment has been to buy a small GPS Bluetooth fob for about $50 that links with my Blackberry and the Google Maps software that I have downloaded to it. As a result, I can now see where I am: a little blue dot on the map marks the spot.

Some BlackBerries - and the new iPhone - have GPS chips embedded but not mine. Before I invested in the GPS fob, I relied on its triangulating my position using mobile phone signals, which worked surprisingly well but was a lot less precise.

To be honest, most of the time I know where I am anyway. The daily commute from Brooklyn to Manhattan, with its grid of numbered streets does not present enormous positioning problems. As long as you remain above Houston and learn the Madison, Park, Lexington, 3rd Avenue sequence, you are more or less set.

Indeed, Manhattan’s canyons of skyscrapers are not very satellite-friendly and it sometimes loses the signal amid them.

But this does not diminish my fascination with watching a little blue dot moving around the map, and it is of more use when I leave the city. I can now find myself even in the swathes of the US that do not have mobile phone coverage.

The other wonderful thing is that it is free, once you have bought the hardware. The GPS signal is free, courtesy of the US Department of Defence’s satellites, and Google software also comes without charge. I do not have to pay for the sophisticated services provided by navigation companies such as Garmin and Tom Tom.

There are limitations, of course. I would not like to use the direction guide on Google Maps while driving along. There is no automated voice telling me when to turn and it would be dangerous to squint at the Blackberry screen for written instructions while in motion.

Still, a free service provides an awful lot of bang for one’s buck.

This brings me to the state of the GPS market. Garmin’s shares fell by 22 per cent on Wednesday after its results showed that GPS demand is not growing as fast as hoped. Margins are being squeezed and the US consumer is more cautious.

From my own experience, I also wonder whether people may not simply substitute cheap and cheerful GPS devices, and mobile phones with GPS chips embedded, for all-singing, all-knowing services offered by such companies. I don’t know where the nearest petrol station is with my BlackBerry but I do know where I am.

July 31, 2008 3:41pm in Finance | Comment