GPS toolkit, software suite for GPS research and development
Chappell, Jeff (Sept. 27, 2007). "ION: Open Source Comes to GPS," GPS World, <http://www.gpsworld.com> (accessed 9 October 2007). pdf file

ION: Open Source Comes to GPS
Sep 27, 2007
By: Jeff Chappell
GPS World
Between military applications and the business that continues to grow exponentially around GNSS and GPS in particular, intellectual property is of paramount importance in this industry—especially considering that the reason for every product is the reception of RF signals freely available to anyone on the entire surface of the planet.

But that hasn't stopped the open-source software movement from coming to GPS applications development.

Attendees here in Ft. Worth, Texas, at the 20th annual ION GNSS show had the chance today to hear from Ben Harris of the University of Texas at Austin. Harris, an engineering scientist at the university's Applied Research Laboratories, is the dedicated evangelist for GPS Toolkit (GPSTk). Harris spoke as part of the presentation track on new product announcements. UT's Applied Research Labs, along with its Space and Geophysics Laboratories, sponsors GPSTk.

GPSTk (which actually isn't all that new, having been around for several years now) is an open-source library and suite of applications for the satellite navigation developer community intended "to free researchers to focus on research, not lower-level coding," as its Web site states. Or as Harris put it, "you shouldn't have to re-invent the wheel to get to your research."

Open source as a concept for software development has been around for some years. As the nonprofit Open Source Initiative puts it, open source is a "development method for software that harnesses the power of distributed peer review and transparency of process. The promise of open source is better quality, higher reliability, more flexibility, lower cost, and an end to predatory vendor lock-in."

Built around the C++ programming language, GPSTk primarily consists of two pieces, the afore-mentioned core library and the suite of applications. The library includes functions such as GPS time, ephemeris calculations, atmospheric delay models, position solutions, mathematics and an application framework. The applications suite includes basic transformations, observation data collection and conversion, file comparison and validation, data editing, ionosphere modeling, and autonomous and relative positioning.

Some engineers might recognize the underlying GPSTk code; much of it traces its roots back to UT Austin's involvement in the GPS Monitoring Station Network (MSN) project; UT Austin Applied Research Laboratories have provided life cycle engineers for the project since 1985.

Everything in GPSTk is available freely under a GNU General Public License. "You can take the application code and modify it to your heart's content," Harris said.

While GPSTk has been around awhile, the project's core team recently established a wiki for the project's documentation, Harris said. A typical wiki, it is a collaborative Web site with content that can be edited by registered users at the project's site, www.gpstk.org. Future plans call for porting specific user manuals into the wiki.

The latest version of GPSTk—1.3, which became available this past summer—can be downloaded from Sourceforge.net, a Web site that serves as a host for myriad open source software projects.