Open Source GPS

1. Open Source GPSToolKit
   The goal of the GPSTk project is to provide a world class, open source computing suite to the satellite navigation community. It is our hope that the GPSTk will empower its users to perform new research and create new applications. GPS users employ practically every computational architecture and operating system. Therefore the design of the GPSTk suite is as platform-independent as possible. Platform independence is achieved through use of the ANSI-standard C++ programming language. The principles of object-oriented programming are used throughout the GPSTk code base in order to ensure that the code is modular, extensible and maintainable. The GPSTk suite consists of a core ibrary and a set of applications. The library provides a wide array of functions that solve processing problems associated with GPS such as processing or using RINEX. The library is the basis for the more advanced applications distributed as part of the GPSTk suite.
     
2. Open Source GPS HOW TO
   On a recent organised cycling ride in the Test Valley down in Hampshire (I'm in the UK), a friend showed me his new toy; a Garmin Edge 305 GPS-enabled bike computer. Being a bit of a gadget head I'd played around with GPS on bike rides before, but the old Garmin GPS 12 I'd had seemed almost the weight and size of a brick, it had a serial interface, and the best use I ever really got out of it was to tell me what my coordinates were, which I could then check back onto an OS map. It also had a hard time finding a signal when surrounded by tall buildings or tree cover. I often find it quite boring riding around the same old familiar routes on my bike, but the alternative, which is figuring out a new route, then stopping every few miles to consult the sweaty OS map in my back pocket spoils the tempo of the ride. My ideal scenario would be to figure out a route beforehand, program it into a GPS, and let it lead me through the new ride. Seeing this new Garmin model rekindled my desire to get this working.
      
3. Open Source GPS Software
   Working with GPS observations is a software-intensive activity. In order to transform receiver products into tangible results, software utilities must be used. Fortunately, many such software utilities have been developed by and for the GPS community but these utilities cannot address the needs of every user. A fundamental goal of the GPSTk is to provide a software library of fundamental operations so that any user can develop custom software and focus primarily on research and development rather than basics. To illustrate the scope of capabilities provided by the GPSTk, it is useful to compare it to existing GPS software projects. These projects generally fall into one or more of the following six classifications: ? Navigation tools. ? Observation extraction and editing tools ? User developed applications. ? Surveying software. ? Scientific research suites. ? Open source projects.
     
4. 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. 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.
       
   
5. Open Source TUX GPS
   The goal of this project is to port uClinux (http://www.uclinux.org/) to the Magellan GPS receivers and write the open source firmware that includes navigational and mapping applications using open map and database formats. This is just a beginning, and it's still a long way to go. This distribution does not pretend to be even a prototype of the operating system with a lot of useful programs. Here I wish to present basically the way how to program, upload the code and run these programs in the GPS receiver, so we all can start testing its hardware. This project might be helpful for studying GPS principles. Having access to the GPS correlator hardware and open source software, you will be able to see the operation of the GPS navigation system from receiving satellites signals to decoding and processing the navigation message, and, finally, to the calculation of the receiver location from the satellites ephemerides and timing data from the signal.
     
6. Open Source Software for Learning about GPS
   Teaching the next generation of engineers about the inner workings of GPS receivers is difficult due to the expense of acquiring appropriate hardware and software. In the past few years a number of excellent books have been written about GPS (references 1 through 5). But, in the end students learn best by doing. Even with hardware available, trying to squeeze the development of software into a quarter or a semester is asking a lot. OpenSource GPS is a C program written in Borland C (version 4.5 and later) without any embedded assembly language. As shown in Figure 3 the software uses a single interrupt routine to handle the tracking loops and find the navigation message. All other functions are handled using a polling method triggered by flags from the interrupt routine.
        
7. New Zealand Open GPS Maps Project
   This is a project to create (and hopefully inspire) an 'open' series of maps for mapping Garmin GPS (Legend, Vista, 60C, 76C etc. Garmin Mapping GPS models). The imported 'grey market' GPS usually have the USA basemap which is good if you live in the States, but pretty ugly for us Kiwis - NZ is an angular blob with most of Auckland in the water. The maps are pretty easy to make, the data and tools required are fairly accessable. I would encourage people to modify and add to the maps I have produced and make them available online. I would love to see a series of Garmin maps that overseas visitors can freely download and enjoy their visit to NZ with local 'points of interest'. The maps I have produced do not overwrite the basemaps in your GPS - the factory basemaps are held in a ROM and not writable.