gnss-sdr/src/algorithms/libs/volk_gnsssdr_module/volk_gnsssdr

Welcome to VOLK_GNSSSDR, the Vector-Optimized Library of Kernels for GNSS-SDR

VOLK_GNSSSDR is a sub-project of GNSS-SDR. This library provides a set of extra kernels that can be used stand-alone or in combination with VOLK's. Please see http://libvolk.org for documentation, source code, and contact information about the original VOLK library.

The boilerplate of this code was initially generated with volk_modtool, an application provided by VOLK that creates the skeleton that can then be filled with custom kernels. Some modifications were added to accommodate the specificities of Global Navigation Satellite Systems (GNSS) signal processing. Those changes are clearly indicated in the source code, and do not break compatibility.

This library contains kernels of hand-written SIMD code for different mathematical operations, mainly with 8-bit and 16-bit real and complex data types, offering a platform/architecture agnostic version that will run in all machines, plus other versions for different SIMD instruction sets. Then, the application volk_gnsssdr_profile runs some iterations of all versions that your machine can execute and annotates which is the fastest, which will then be selected at runtime when executing GNSS-SDR. In this way, we can address at the same time portability (by creating executables that will run in nearly all processor architectures) and efficiency (by providing custom implementations specially designed to take advantage of the specific processor that is running the code).

These kernels have some specific features (e.g. saturation arithmetics) that are aimed to GNSS signal processing, but could make them not suitable for its general use in other applications. Check out the documentation generated by Doxygen and the generic (that is, plain C) implementation to see what each kernel is actually doing.

How to use VOLK_GNSSSDR:

This library is automatically built and installed along with GNSS-SDR if it is not found by CMake on your system at configure time.

However, you can install and use VOLK_GNSSSDR kernels as you use VOLK's, independently of GNSS-SDR.

First, make sure that the required dependencies are installed in your machine:

$ sudo apt-get install cmake python-mako python-six libboost-dev \
  libboost-filesystem-dev libboost-system-dev

Please note that if you are using a compiler supporting the C++17 standard (for instance, gcc >= 8.0), specifically the std::filesystem library, packages libboost-dev, libboost-filesystem-dev and libboost-system-dev are no longer required dependencies. The CMake script will detect that availability for you.

In order to build and install the library, go to the base folder of the source code and do:

$ mkdir build
$ cd build
$ cmake ..
$ make
$ sudo make install

That's it!

Before its first use, please execute volk_gnsssdr_profile to let your system know which is the fastest available implementation. This only has to be done once:

$ volk_gnsssdr_profile

From now on, GNSS-SDR (and any other program of your own that makes use of VOLK_GNSSSDR) will benefit from the acceleration provided by SIMD instructions available in your processor.

The execution of volk_gnsssdr_profile can be set automatically after building, leaving your system ready to use:

$ cmake -DENABLE_PROFILING=ON ../
$ make
$ sudo make install

This figure shows the role of some VOLK_GNSSSDR kernels in the context of a GNSS baseband processor:

If you use VOLK_GNSSSDR in your research and/or software, please cite the following paper:

• C. Fernández-Prades, J. Arribas, P. Closas, Accelerating GNSS Software Receivers, in Proc. of the ION GNSS+ 2016 Conference, pp. 44-61, Portland, Oregon, Sept. 12-16, 2016.

Citations are useful for the continued development and maintenance of the library.

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VOLK_GNSSSDR was originally created by Andres Cecilia Luque in the framework of the Summer Of Code In Space (SOCIS 2014) program organized by the European Space Agency, and then evolved and maintained by Carles Fernández-Prades and Javier Arribas. This software is released under the GNU General Public License version 3, see the file COPYING.

This project is managed by Centre Tecnologic de Telecomunicacions de Catalunya.