Dual-target magnetic anomaly detection and recognition based on a board-level micro fully integrated fluxgate tensor for unexploded ordnance (UXO) mission.

To meet the application requirements for detecting UXO using magnetic detection, the micro fluxgate tensor technology has shown significant value in target recognition, localization, and interference resistance. A board-level micro fluxgate tensor is developed using heterogeneous multi-dimensional integrated triaxial fluxgate technology, achieving synchronous detection and identification of dual targets. The micro fluxgate tensor consists of a typical cross-array formed by four MEMS integrated triaxial fluxgate sensors bonded onto a PCB board, with the size of each triaxial sensor being 17.4 mm × 13.3 mm × 13.8 mm, and the overall size of the micro fluxgate tensor being 86 mm × 80 mm × 16 mm. The micro fluxgate tensor uses a total of 12 uniaxial MEMS fluxgate chips, the size of each chip being 10.8 mm × 6mm × 0.5mm, with an average sensitivity of approximately 1930 V/T and a noise power spectral density below 0.05 nT/√Hz @1Hz. Within a test area of 1.2m × 1.2 m, two differently shaped magnetic targets, an olive-shaped magnet and a spherical magnet, are detected by the micro fluxgate tensor successfully. By comparing the magnetic tensor figure aspect ratios of the olive-shaped magnet (175%) and the spherical magnet (122%), the two targets are distinguished. Furthermore, the magnetic field tensor detection of coexisting cylindrical and spherical magnets is performed, and the results of the magnetic tensor figure indicate the presence of both targets and achieve identification differentiation based on shape aspect ratios, with aspect ratios of 241% and 132% respectively. The micro fluxgate tensor will have advantages such as integration, miniaturization, lightweight design, and low power consumption. It will be more suitable for deployment on portable platforms and unmanned systems, thereby enhancing the efficiency of UXO detection.