Do it your self DGPS reciever

I decided that I wanted a cheap low cost DGPS reciever so my solution is to build one.

This project is just starting but is brought to you by:
• Jim Bixby Ready to build schematics
• Tim Hogard -- Keeper of messy notes & webmaster
• Larry Burg of Purple Computing. and the first sharehardware project.
• More to come....

The early ideas involved using a FGPA or the Skiper Chip by Pacific Crest but that seems oever complicated and the Skiper Chip hasn't been seen.

One of my posts

Subject: Homebrew DGPS PLL
Newsgroups: sci.geo.satellite-nav

I've started looking into RF design. There is a resaons I stay digital... Either way, I've found two chips that I think will generate the needed 284.0->325.0khz that is needed. The first choice is the National Semiconductor LMX1501A which is about $7.32 from digikey. With a crystal that would build the basics of the synthesizer for under $10 in homebrew quantites. The other choice of a chip is the Motorola MC145173 which is a much better choice but harder for the hobbist to find. I also checked into basic stamps at the local electronics shop and they do look like a reasonable solution to the 50/200 baud reframer and they can be found easily. I would personlay prefer the 6811 but thouse are a bit too hard to find in small numbers.

If anyone develops anything worthwile, I've got a web and ftp server that can be used to share info that shouldn't go in the newsgroup.

Peter's FTP site (The GPS archive):
ftp://sundae.triumf.ca/pub/peter
http://vancouver-webpages.com/pub/peter/index.html

WE7U's GPS Links (including the DGPS FAQ)
http://www.eskimo.com/~archer/gps.html

Low cost PIC-Programmer for PIC16C84 etc:
http://www.ebar.dtu.dk/~c888600/newpic.htm

DGPS Receiver Project (also see FTP link near bottom of page):
http://home1.gte.net/clseng/DGPS_index.htm

'Software' based DGPS decoder software (from the above FTP link):
ftp://ftp.netcom.com/pub/rc/rcochran

Adventures in GPS antenna construction:
http://www.scott-inc.com/html/gpsant.htm

Homemade Helical GPS Antenna:
http://www.geocities.com/TheTropics/Cabana/4340/gpsant.html

Sam's GPS raw data pages (Build a OEM GPS):
http://callisto.worldonline.nl/~samsvl/

And an amazing well organized site with tons of GPS related links that I sure will be helpful -- Sam Wormley's Navstar (GPS) Resources:
http://www.cnde.iastate.edu/gps.html