Multithreaded Parallel Estimation for Global Ionospheric Model by Using OpenMP

The application of multithreaded parallel technology using OpenMP for global ionospheric modeling is discussed. The vertical total electron content(TEC) is modeled in a solar-geomagnetic reference frame using a spherical harmonics expansion up to degree and order 15. Comparison results between 1-day, 3-day solutions in this paper and IGS products are investigated. Root mean square of difference of TEC maps is approximately 3-5 TECU. There is a better agreement between the first and the last TEC maps of a 3-day solution and IGS products compared with those of 1-day solution. The difference in differential code bias (DCB) for satellites and receivers, comparing our solutions and IGS products were around 0.2 ns and 2 ns, respectively. Only a few DCB values for receivers on a few days are beyond 3-4 ns. In this study, a Dell R730 with 2 CPUs, 8 cores, 32 threads, and 128 GB memory was used for testing ionosphere modeling. Results show that multithreaded parallel computing using OpenMP promotes the efficiency of global ionospheric modeling. The time consumption of 1-day solution and 3-day solution are approximately 7 minutes and 22 minutes, respectively. The efficiency of modeling is promoted by nearly eight times. Thus, multithreaded parallel technology with 3-day solution could not only save time costs efficiently, but also improve the precision of the ionosphere model. It also brings convenience for modeling algorithm testing, fast release of ionosphere products, and verification and prediction of products. This technology provides a reference value for fast modeling of the global ionosphere using multi-GNSS measurements.