Improvement of DDM Preprocessing for the Simulation of the GRAVES Radar Densified Sparse Array for Space Surveillance and Tracking

In a recent work (A. Jouadé and A. Barka, “Massively parallel implementation of FETI-2LM methods for the simulation of the sparse receiving array evolution of the GRAVES radar system for space surveillance and tracking, IEEE Access, vol. 7, pp. 128968-128979, 2019), we have discussed our implementation of the finite-element tearing and interconnecting (FETI) method and the domain decomposition method (DDM) for the full-wave simulation of the large GRAVES sparse array (60 m diameter disk). Owing to the nonregular distribution of the antennas of the sparse array, such simulations in reasonable times are not accessible with existing FETI methods optimized for repetitive geometries, which do not benefit from an effective parallelization technique. A particularity of the preprocessing step of our DDM is that the complete sparse array mesh is not built upstream of the resolution of the electromagnetic problem. Each subdomain in our decomposition is equipped with its own local mesh, belonging to a limited set of unit-cell meshes, generated separately. Initially, a total of 13 692 subdomains were chosen among three types of subdomains, considering those corresponding to antennas (200), air subdomains (800), and ground plane subdomains (12 592). This simulation has required 13 692 Intel Xeon Broadwell E5-2680v4 processing cores equipped with 4 GB of memory, each handling one subdomain. A new strategy is shown, which requires only 2408 cores for the same simulation, leading to an 82.41% reduction in the required number of cores, as well as a 30% reduction in the simulation time.