It is of great importance for pipeline systems to be is efficient, cost-effective and safe during the transportation of the liquids and gases. However, underground pipelines often experience leaks due to corrosion, human destruction or theft, long-term Earth movement, natural disasters and so on. Leakage or explosion of the operating pipeline usually cause great economical loss, environmental pollution or even a threat to citizens, especially when these accidents occur in human-concentrated urban areas. Therefore, the surveying of the routed pipeline is of vital importance for the Pipeline Integrated Management (PIM). In this paper, a comprehensive review of the Micro-Inertial Measurement Unit (MIMU)-based intelligent Pipeline Inspection Gauge (PIG) multi-sensor fusion technologies for the transport of liquids and gases purposed for small-diameter pipeline (D<30cm) surveying is demonstrated. Firstly, four types of typical small-diameter intelligent PIGs and their corresponding pipeline-defects inspection technologies and defects-positioning technologies are investigated according to the various pipeline defects inspection and localization principles. Secondly, the multi-sensor fused pipeline surveying technologies are classified into two main categories, the non-inertial-based and the MIMU-based intelligent PIG surveying technology. Moreover, five schematic diagrams of the MIMU fused intelligent PIG fusion technology is also surveyed and analyzed with details. Thirdly, the potential research directions and challenges of the popular intelligent PIG surveying techniques by multi-sensor fusion system are further presented with details. Finally, the review is comprehensively concluded and demonstrated.

中文翻译：

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基于微惯性测量单元的小直径管道测量智能PIG多传感器融合技术的全面综述。

对于管道系统而言，在液体和气体的运输过程中保持高效，成本效益和安全性至关重要。然而，由于腐蚀，人为破坏或盗窃，长期的地球运动，自然灾害等原因，地下管道经常会发生泄漏。工作管道的泄漏或爆炸通常会造成巨大的经济损失，环境污染，甚至对市民造成威胁，特别是在这些事故发生在以人为中心的城市地区时。因此，路由管道的测量对于管道集成管理（PIM）至关重要。在本文中，展示了对基于微惯性测量单元（MIMU）的智能管道检查规（PIG）多传感器融合技术的全面综述，该技术用于输送用于小直径管道（D <30cm）测量的液体和气体。首先，根据各种管道缺陷检查和定位原则，对四种典型的小口径智能PIG及其相应的管道缺陷检查技术和缺陷定位技术进行了研究。其次，将多传感器融合管道测量技术分为两大类，即非惯性和基于MIMU的智能PIG测量技术。此外，还详细调查和分析了MIMU融合智能PIG融合技术的五个示意图。第三，详细介绍了多传感器融合系统中流行的智能PIG测量技术的潜在研究方向和挑战。最后，对审查进行了全面总结和论证。