You can receive GPS indoors

AFTER I WROTE my Garmin piece earlier in the week, many people pointed out you can't receive GPS signals indoors, so my little daydream of being able to log footsteps inside the confines of the Las Vegas Convention Center was, well, lame.

Guess what bunkies! - you can receive (and process) GPS signals indoors (Yes, this is almost magic, but follow along). Cellular phones of all shapes and sizes are hitting the marketplace with GPS incorporated to provide location for emergency services responses, no secret there. And the models do work indoors, maybe not common knowledge...

Since July 2001, Global Locate has demonstrated indoor GPS solutions using dedicated silicon. And I don't mean standing-under-the-awning indoors, but indoors inside a brick building with no windows and in the mini-bar fridge in a hotel room working. Global Locate and Fujitsu announced a single-chip solution for cell phones in February 2002, as reported here. The Global Locate solution can be supplemented by an "Assisted GPS" server for higher accuracy.

However, dedicated silicon might be passe. Philips Electronics reports it has developed a software processing technique (see here) with no specialized hardware required, just a standard CPU and a DSP. To quote the article directly, "The sensitivity can be 100 times higher than with conventional receivers, thus enabling indoor reception of GPS signals.... This new approach will allow GPS receivers to be built into devices normally used indoors, such as mobile phones and PDAs."

So, even if a new Garmin gadget available at end of year won't work indoors, other vendor products likely will ... or in the case of Global Locate, do. And we haven't gotten 'round to the next-generation GPS schemes that are currently being discussed for future implementation. µ