## 3 Validation of MANTiS-32 Sensing Performance
### Evaluation of Measurement Performance of the MANTiS-6050 Sensor  
To validate the acceleration measurement accuracy of the MANTiS-6050 sensor, a series of controlled excitation tests were performed using an electrodynamic shaker system (Sonic Dynamics Inc., Suzhou, China). In this experimental setup, known input vibrations were applied to the sensor, and the measured responses were compared against the excitation signals to assess the sensor's fidelity and precision. As illustrated in Figure 8, the test configuration included the MANTiS-6050 sensor module interfaced with the MANTiS-32 wireless communication unit, both mounted on the shaker table. A wireless repeater and an access point (A3004T, ipTIME; 2.4 GHz Wi-Fi) were positioned 10 m from the setup to establish a real-time data transmission environment representative of field conditions. The  
Figure 7: Verification results of the MANTiS-6050 sensor.  
excitation frequencies were selected within the range of 5 Hz to 20 Hz, corresponding to the typical fundamental frequencies of small- to medium-span bridge structures. Based on the Nyquist sampling criterion and to enhance spectral resolution, the sampling rate was set to 100 Hz, equivalent to five times the highest input frequency. Real-time acceleration data were collected over 60 s intervals for each test condition.  
The input amplitude was incrementally increased from 0.1 g, in steps of 0.1 g, while the input frequency varied from 5 Hz, in 0.5 Hz increments. These excitations were applied sequentially to the x-, y-, and z-axes across sensors #1 through #6. The corresponding measured signals were then compared with the input references, and the results are summarized in Table 2. As reported in Table 2, the average error in amplitude measurements was found to be 0.91%, while the average deviation in frequency was 0.40%. These results indicate that the MANTS-6050 sensor maintained high measurement fidelity, with both amplitude and frequency errors consistently within 1%. Such performance demonstrates the sensor's strong potential for reliable acceleration monitoring in structural health applications, particularly in small- to medium-scale bridge systems.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \multicolumn{2}{c}{**Division**} & \multicolumn{3}{c}{**Excitation**} & \multicolumn{3}{c}{**Measurement Results**} \\ \hline \multirow{2}{*}{**Sensor No.**} & \multirow{2}{*}{**Axis**} & **Amp.** & **Freq.** & **Amp.** & **Error** & **Freq.** & **Error** \\  & & **(g)** & **(Hz)** & **(g)** & **(\%)** & **(Hz)** & **(\%)** \\ \hline \multirow{4}{*}{1} & \multirow{2}{*}{\(x\)} & 0.1 & 5.0 & 0.10 & 0.0 & 4.97 & 0.60 \\ \cline{2-8}  & & \(y\) & 0.7 & 8.0 & 0.69 & 1.4 & 7.97 & 0.38 \\ \cline{2-8}  & & \(z\) & 1.3 & 11.0 & 1.28 & 1.5 & 10.95 & 0.46 \\ \hline \multirow{4}{*}{2} & \multirow{2}{*}{\(x\)} & 0.2 & 5.5 & 0.20 & 0.0 & 5.48 & 0.36 \\ \cline{2-8}  & & \(y\) & 0.8 & 8.5 & 0.80 & 0.0 & 8.45 & 0.59 \\ \cline{2-8}  & & \(z\) & 1.4 & 11.5 & 1.38 & 1.4 & 11.47 & 0.26 \\ \hline \multirow{4}{*}{3} & \multirow{2}{*}{\(x\)} & 0.3 & 6.0 & 0.30 & 0.0 & 5.98 & 0.33 \\ \cline{2-8}  & & \(y\) & 0.9 & 9.0 & 0.89 & 1.1 & 8.97 & 0.33 \\ \cline{2-8}  & & \(z\) & 1.5 & 12.0 & 1.48 & 1.3 & 11.95 & 0.42 \\ \hline \multirow{4}{*}{4} & \multirow{2}{*}{\(x\)} & 0.4 & 6.5 & 0.40 & 0.0 & 6.48 & 0.31 \\ \cline{2-8}  & & \(y\) & 1.0 & 9.5 & 0.99 & 1.0 & 9.45 & 0.53 \\ \cline{1-1} \cline{2-8}  & & \(z\) & 1.6 & 12.5 & 1.58 & 1.3 & 12.45 & 0.40 \\ \hline \end{tabular}
\end{table}
Table 2: Performance assessment results of the MANTiS-6050 accelerometer.  
Figure 8: Experimental setup for validating the acceleration measurement accuracy of the MANTiS-6050 sensor.