The GPL-GPS Project

Introduction Software Hardware Resources News Blog Contacts

New Project 2008/02/13

Because the MG5001 board that the GPL-GPS project is based on is no longer available, and it may be that the GP4020 chipset isn't going to be available for a long time, either, we've started an exploratory new project: can we recreate the GP4020/GP2021 correlator in a low-power programmable device, like a CPLD? In other words, can we ditch the custom silicon completely? The UNSW SNAP people have already with their Namuru FPGA GPS receiver:

The only thing needed now is to make it small, low power, and dumb it down a bit for embedded use. Maybe CPLDs?

Welcome to the home of the GPL-GPS Project

This site is the home for the GPL-GPS ("General Public License"-GPS) project, an effort to bring free and open source software to inexpensive, commercially-available OEM (Original Equipment Manufacturer) GPS receiver boards. The GPL-GPS software is based on on Clifford Kelley's OpenSource GPS software. There are many different open source and open hardware GNSS projects; you can find a list of them here.

Note that GPL-GPS is not mapping software or any kind of communication toolkit for talking with commercial receivers; rather, it is firmware that is meant to run on the receiver board itself, giving you direct access to the GPS chipset.

News 2006/09/30: GPL-GPS clas taught at ION GNSS 2006, GPL-GPS merging back with OSGPS is possible, GPL-GPS instructions being updated.

What You'll Need

To develop software with GPL-GPS, you'll need the following:

It's a long process, but when you're done you'll have a completely open source GPS receiver development system!

The Motivation

The motivation for GPL-GPS is the desire for advanced features in an inexpensive receiver. Currently, all OEM GPS receivers - i.e., the single GPS receiver boards with no case, display, etc - have closed-source, proprietary firmware which makes certain assumptions on the system dynamics or application which may not be appropriate. By using open source firmware on these boards, the end user may optimize their receiver's firmware for their application. Applications include:

Current Status (2006/09/06)

GPL-GPS is currently up and running using the eCos real time operating system and very modified version of Tak's port of OpenSourceGPS. It's currently positioning, with errors down in the 100's of meters. This is fine, considering there's nothing fancy in the positioning code, not even ionospheric/tropospheric corrections or averaging. Next on the agenda: optimizations, features, and more fancy things. And work on the tracking loops, which drop satellites like hot potatoes.