Hey, I know you already support 3 gps modules… maybe that’s why I figure you’re into them…
At any rate… these guys at uBlox have made a GPS module that will track (accurately) indoors… You can stick the antenna in a tin can, under the seat of your car, and it will still track! it can track with the patch antenna under the vehicle pointing down!, they have an awesome field test report on their website, check it out!
The only thing stopping me from picking one of these up is the dev kit is over $600.
heres the link to the part
http://www.u-blox.com/products/tim_lh.html
Heres the link to the field test report
http://www.u-blox.com/products/Product_ … 04004).pdf
Maybe I have "Spark"ed your interest 
Dan K
Oh no, we’ve actually carried a UBlox receiver awhile back. It was a pretty crumby early engine - nothing like what ublox has these days. They always had good datalogging built into some units as well!
The case study is a nice one, but not all that unique. The TF30 and UV40 are great, sturdy units but only operate with a good view of the sky. The Lassen iQ on the other hand has a higher sensitivity mode that will allow it to perform similarly to the ublox units. Equal? Maybe. I’ve tracked 4-5 satellites taking the antenna from outside (to get a lock) into the middle of my house. Position bounces around a bit but I can keep a lock. Scary to think the signal to noise ratio is rediculous to begin with - these new receivers have some amazing filters built into them…
-Nathan
Yeah, where i work we use the lassen units, but we’ve just got in the uBlox devkit as well for testing… We’re gonna give them the pepsi challenge… I’ll post back the results.
Anyone know of a good circuit for a combiner for the lassen? Need to combine or switch the internal antenna with an external antenna. Space is at a premium as well, so It can’t be too big. We had a custom one made but it seems extremely lossy. Maybe it just needs tuned… I dunno.
Thanks,
Dan K