A USB GNSS radio front-end (designed by Dennis Akos) is available and it is matched to the GNSS SDR book. Since the publication time of book there were several iterations of the front-end versions. The front-end does not come with the book, but instead can be bought on an online electronics store (Sparkfun). Please visit the homepage of the front-end for more details and the original USB drivers at ccar.colorado.edu/gnss/.
There are also front-ends from other manufactures, which will work with our SDR, but in some cases the SDR code must by modified. For example a few versions of such GNSS front-ends are manufactured by Nottingham Scientific Limited (a custom front-end version by NSL is shown in the picture at the top of this page). These front-ends are based on a very flexible GNSS front-end chip from Maxim. In addition these front-end employ a hardware data packing which reduces the USB data rate from 16MB/s to 4MB/s.
Other examples are wideband front-ends for professional applications like the one from Fraunhofer IIS that can be also connected using USB or other interfaces.
DGC’s Alternative Driver for the Front-end from Dennis Akos
Note this section is here for support of legacy code and hardware. This driver was designed and tested to work with the first version of the front-end!
The Danish GPS Center has developed an alternative driver for this front-end. The driver was tested only on Windows XP and only using the first version of the front-end.
Update! Application code was updated on 04/02/2011 to fix a bug (internal data corruption). Download.
The Danish GPS Center recorder application or driver do not have any inbuilt record length limitations. The longer the signal records are the higher is chance that the PC might not be able to keep up writing data to the hard disk. The recorder application might report this kind of error: “ERROR! Buffer overrun in the GNSS Front-end! Recording stopped.”. It means that the PC could not keep up with the incoming data from the front-end. Usually the processor speed is not the crucial factor here. The most important is the speed of the hard disk. Disk speed depends on several factors, but the most important are its file fragmentation, disk technology, speed (in particular notebook disks used to be slow). Also note that the disk speed is reduced when the disk is nearly full. In addition Windows services can interfere with the recording process by performing their own reading/writing operations which will further reduce the disk writing speed.
How to Import USB Recorder Code into Microsoft Visual Studio
Here are instructions how to import the recording application source code into Microsoft Visual Studio 2005.
- In Visual Studio select menu item: “File”->”New”->”Project From Existing Code…”
- In the wizard window set project type to “Visual C++” and click “Next”
- Field “Project file location:” must contain full path to the source code of the application (e.g. the code that is contained in folder “app source code”)
- Enter some name for the project
- Click “Next”
- Make sure “Use Visual studio” option is selected
- Change “Project Type:” to “Console application project”
- Make sure that none of the other options are selected
- Click “Finish” (the rest of the options in the wizard do not have to be changed)
After this you should be able to build (compile) the VC project.