A SIMD intrinsic correlator library for GNSS software receivers

An open-source implementation of a code division multiple access software correlator library that leverages single instruction multiple data (SIMD) is presented. We initially discuss the key aspects involved in the correlation operation for software radio applications. Afterward, we present the state-of-the-art application programming interface that provides SIMD capable methods for each of the components in a correlation operation, including the first of its kind parallelized code and carrier generation using lookup tables and SIMD instructions. The library was developed using SIMD intrinsic instructions, which are a C-type nomenclature offering access to the assembly instructions originally designed for the SIMD extensions in the processor. This design paradigm presents an advantage in terms of readability and simplified code development to accommodate future modifications. Recorded data were used with a standalone global navigation satellite system software receiver where the methods hereby presented were tested and profiled to validate theoretical assumptions.