Metrological Challenges in Collaborative Sensing: Applicability of Digital Calibration Certificates

Abstract

IoT systems based on collaborative sensor networks are becoming increasingly common in various industries owing to the increased availability of low-cost sensors. The quality of the data provided by these sensors may be unknown. For these reasons, advanced data processing and sensor network self-calibration methods have become popular research topics. In terms of metrology, the self-calibration methods lack the traceability to the established measurement standards of National Metrology Institutes (NMIs) through an unbroken chain-link of calibration. This problem can be solved by the ongoing digitalization of the metrology infrastructure. We propose a conceptual solution based on Digital Calibration Certificates (DCCs), Digital SI (D-SI), and cryptographic digital identifiers, for validation of data quality and trustworthiness. The data that enable validation and traceability can be used to improve analytics, decision-making, and security in industrial applications. We discuss the applicability and benefits of our solutions in a selection of industrial use cases, where collaborative sensing has already been introduced. We present the remaining challenges in the digitization and standardization processes regarding digital metrology and the future work required to address them.

Secure Exchange of Digital Metrological Data in a Smart Overhead Crane

“…The formats can be unstructured, semi-structured, or structured, which means that the data can be very heterogeneous. The data from low-cost IoT sensors are often unstructured, which means that there are very few if any metadata included in the data samples describing the context of the measurement, which limits the value of the data as the data quality and trustworthiness of the data are largely unknown [13,30]. Unstructured data formats also quickly lead to interoperability issues.…”

“…This sets limits for the potential usefulness of the data. These problems are commonly addressed with the use of different types of post-processing methods [12,13]. In addition, IoT solutions have typically been based on at least partially closed systems where the data collected have been stored and used more or less locally, e.g., at manufacturing facilities.…”

“…Thus, it has become somewhat of a limiting factor in the digitalization of industrial quality management processes. The digitalization of metrology pursues offering the means for the correct interpretation of the data and having the important metadata, such as measurement uncertainty and traceability information, available for use in automated IoT systems, e.g., via digitized data formats offering the capability for machine reading and processing of these data [12,13,17,18]. In this paper, we refer to these data or metadata for presenting the metrological information in a machinereadable and interpretable format as digital metrological data.…”

Toward Smart Traceability for Digital Sensors and the Industrial Internet of Things

“…This requires novel approaches for the representation and distribution of calibration data. Therefore, the European research project titled SmartCom [ 8 ] addresses the communication of metrological information in digital infrastructures. Our work here extends the recently published work from [ 8 ] on digital calibration certificates in sensor networks by an investigation of the potential use and benefits of integrating such metrological information in a sensor network.…”

“…Therefore, the European research project titled SmartCom [ 8 ] addresses the communication of metrological information in digital infrastructures. Our work here extends the recently published work from [ 8 ] on digital calibration certificates in sensor networks by an investigation of the potential use and benefits of integrating such metrological information in a sensor network. That is, we consider the availability of information, such as calibration data, and address the utilization of this information to achieve traceability in the IoT.…”