Long story short: here you can find only some basic info about my old and no longer developed project. More info is available on Polish version of this page.

Based on cheap Axiom gps module (Sirf II) available on auctions I made a gps logger. Main goal was to provide at least a day of uninterrupted track logging with full resolution (i.e. logged everything from gps every second). To achieve it I used laptop Li-ion batteries, step-down switching voltage regulator (for efficiency) and SD card to store logs.

Because Axiom didn’t have antenna, I also made it myself based on this document: http://www.arrl.org/files/file/Technology/tis/info/pdf/0210036.pdf, sorry no pictures.

This logger was also used in high altitude baloon project few times: in missions CP03, CP04 (landing in lake 🙂 ) and CP05 AFAIR
During CP04 Axiom broke because of landing in water and not so sealed capsule. After that I connected a ‘mouse’ USB gps module based on Sony chipset. Luckily it was equipped with usb to serial interface, so pure ttl serial was also available inside – just to connect logger.
I had a plans to make smaller version of logger using microSD card and try to put everything except battery to ‘mouse’ module but I didn’t made it…

Software is opensource and I even set up a project on Sourceforge for it 🙂
You can download it here: http://sourceforge.net/projects/avrgps/files/
Because software haven’t filesystem support, it writes data just to raw sectors, so to recover it you should use dd under Linux or similar tool on ohter OSes.
To check how many sectors are already written on card, use serial port and some terminal (for example minicom). Using console you could also reset sectors counter to log from beggining of SD card.

Pictures of ready device:

Schematic:

AVRGPS 2.0

2007.02.13, first LCD code:

2007.02.20, parse GPRMC and display some basic data, LCD library done:

2007.03.06, parse GPGSA and GPGSV, math library done, added flying sats:

Update 2012.09.22
Sadly, project is dead. I use logger sometimes but in ‘gps everywhere’ era I just use my phone for logging.
But for completness I made english version of this page after moving it into my blog.
I think that sources of beta version with Siemens S65 lcd I put somewhere in near future 🙂