High-speed train positioning method based on motion constraints suppressing INS error in tunnel

When the high-speed train is running in tunnel, global navigation satellite system (GNSS) signal completely lost, and only relying on inertial (INS) composed of micro electro mechanical (MEMS) devices makes large error. To solve this problem, a method considering installation angles measurement unit (MIMU) relative to body for motion constraints aided (CIAMC-INS) proposed, which does not need extra sensors. This first establishes model based MIMU; secondly, effect turning analyzed, use condition obtained; then, MIMU are estimated when GNSS good met; finally, applied suppress error pure (P-INS) improve accuracy tunnel. Based method, tests carried out both real tunnel environment case artificially disconnected signal. The experimental results show that significantly improved, verifies effectiveness method.