Instrumentation & Measurement Magazine 25-1 - 28

Multi-Sensor Measurement
and Data Fusion
Zheng Liu, George Xiao, Huan Liu, and Hanbing Wei
T
here is a growing demand for a reliable and comprehensive
measurement of critical quantities in modern
industry. As any individual sensor or measurement
does not reflect the overall properties of the object, the use of
multiple sensors becomes essential. The industrial Internet
of Things finds a diverse range of applications. Accordingly,
the ability to handle multi-sensor measurement data is very
important. Data fusion, also known as information fusion,
can produce more consistent, accurate, and reliable information
by integrating the data from multiple sources. Instead of
achieving only low-level outputs, data fusion facilitates the
information flow from raw data to high-level understanding
and insights, which serve as the evidence for industry decision-making.
This paper presents a big picture of multi-sensor
measurement and data fusion.
Conventional Measurement System
A measurement system provides information about the
physical value of the variable being measured [1]. A typical
measurement system consists of several elements, as shown in
Fig. 1. The sensor is the first
element and gives an output
which is a function of
the measurand. The signal
conditioning manipulates
an analog sensor signal to
meet the requirements for
further processing, such as
analog-to-digital convertion.
An analog-to-digital
converter (A/D or ADC)
is employed to convert an
analog signal into a digital
signal, which can be easily
processed with a computer.
The signal processing will
improve the sensitivity and
resolution of the measurement
through amplifying
28
and filtering operations. Some measurement systems may
have a signal transmission unit to a remote point for output
and display. In the conventional measurement system, the processing
of the measurement data or signal is to achieve better
quality, while a quantification analysis is possible if a proper
calibration has been properly set up.
Multi-sensor Measurement System
Multiple sensors are often employed in a measurement system
for three different scenarios. In the first scenario, a secondary
sensor or multiple sensors will be used if the primary sensor is
affected by the environmental conditions in which the primary
sensor is operated. The secondary sensor(s) could provide an
appropriate correction to the measurement by the primary
sensor. In the second scenario, where the direct measurement
is not available, the target measurand can be calculated from
multiple related variables measured by multiple sensors, as
illustrated in Fig. 2. The target measurand y can be calculated
from the indirect measurement
xx, , x with a function
12 3
fx ,  ,x x .
12 3
Fig. 1. The elements of a measurement system.
Fig. 2. Indirect measurement with multiple sensors.
IEEE Instrumentation & Measurement Magazine
1094-6969/22/$25.00©2022IEEE
February 2022
Instrumentation & Measurement Magazine 25-1

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