A problem with GPS units is that they consume a lot of power, due to their antennae collecting data from satellites on a non-stop basis.
Now we learn from Imaging-Resource (a digital camera Web site) about a new GPS data collector that consumes so little power that it (apparently) can run a year on a single lithium button battery. There is much detail at I-R (including a link to a video interview), but here is a taste of how it works:
Rather than try to do all the processing that's normally required for computing a GPS fix, the NXP device simply takes a digital "snapshot" of the raw GPS data whenever it wakes up. This only takes a tenth of a second, and consumes almost no power. Later (back on your computer), their client software queries a server they maintain, that's continuously logging the detailed "ephemeris" data for all 32 GPS satellites.
This system works only when you can wait to get to an Internet-enabled computer, to download the complete GPS data. I-R sees all digital cameras as an obvious application; but this system isn't going to work for tourists relying on handheld GPS units in the twisty streets of downtown Prague.