Do it your self DGPS reciever

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

So far we have two options. One is to build our own FPGA or to use the Skiper Chip by Pacific Crest.

Subject: Homebrew DGPS PLL
Newsgroups: sci.geo.satellite-nav
So I need a cheap DGPS reciever so I'm going to have to build my own.

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.

Subject: Re: Homebrew DGPS PLL
Date: Wed, 08 Apr 1998 12:38:01 GMT
Message-ID: <>

I'm WAY out of my league in this thread (I can build kits, but I sure can't
design them!), but here are all the links that I have that might be of some
help to this project.

DGPS Receiver Project (also see FTP link near bottom of page):

'Software' based DGPS decoder software (from the above FTP link):

Adventures in GPS antenna construction:

Homemade Helical GPS Antenna:

Sam's GPS raw data pages (Build a OEM GPS):

And an amazing well organized site with tons of GPS related links that I
sure will be helpful -- Sam Wormley's Navstar (GPS) Resources:
If you want to help with this, please let me know at

Back to Tim's Homepage