An interesting and viable approach to GPS photo tagging

During research for this project I came across this product. Basically all it does it take a GPS sample every 15 seconds and store this in memory - date and time stamped based on the GPS time. When connected to the computer some cleaver software compares the time when each photo was taken to the GPS measurements at that point and inserts the relevant GPS data. I'm thinking this is quite a viable alternative and since I already have most of the hardware this is the path I'm looking at travelling along.

The plan in short:
- An AT-Mega128 will be used to read in GPS data from my GPS receiver at say 10 second intervals. It will strip off most of the unneeded stuff - just keeping the time/date stamp, the lat, long and alt.
- The micro will then write this data to an SD memory card though a DOSonChip interface
- I will probably use some cleaver perl scripts to parse the photos and correlate their time taken with the GPS logs. From there the script will insert the relevant GPS data into the Exif header of the jpeg files.
- One further enhancement would be to make the GPS unit nice an compact and mount it on the hot shoe of the camera. That way each time the camera takes a picture, GPS data could be logged onto the SD card. The same scripts would be used to match up this GPS data with the specific photographs. Though this approach may be more elegant - it seems to be less practical (extra stuff hanging off the camera - and wouldn't be adaptable - ie. if I wanted to use it onboard one of my aircraft) so possibly I will go for the first option, but add some additional trigger points which could be wired to a wireless transceiver at a later stage.