Shielding Damage Characterization in Twisted Pair Cables Using OMTDR-based Reflectometry and Inverse Problems

Aeronautical wiring and interconnect systems are highly exposed to severe conditions leading to serious security problems. In such systems, the predictive diagnosis of incipient faults becomes an economic and human requirement in the perspective of predictive maintenance. This paper proposes to study and develop methods and models to detect incipient faults and characterize them in wiring and interconnect systems. A model-based inversion process combined with optimization-based algorithms have formed a suitable, reliable and efficient technique for incipient fault characterization when processed with reflectometry. To do so, a shielded twisted pair cable with a shielding damage has been modeled using Finite element method and simulated using reflectometry. It consists in injecting a wideband test signal down to the cable and recording the reflected echoes at each impedance discontinuity. The analysis of the reflectometry-based measurements permits to detect and locate incipient fault. A Genetic Algorithm (GA) is then performed to estimate the fault's features such as length, width or per-unit-length parameters (RLCG), etc., which becomes equally interesting for predictive maintenance. The proposed methodology is validated by experimental results using an electronic card including Xilinx Zunq 7010 FPGA to inject/receive Orthogonal Multi-Tone Time Domain Reflectometry (OMTDR).