## 4 Conclusions  
This study detailed the measurement uncertainty associated with the instrument chain used to measure rocket motor thrust and evaluated the uncertainty associated with the numerical integration of these measurements using the trapezoidal method to determine total impulse. The measurement uncertainty in the thrust acquisition of static firing test at the Propulsion Jets Testing Laboratory of the Brazilian Army Technological Center resulted in a value of 5.8932 N (0.24%). This magnitude is considered low, indicating significant reliability in the data obtained during the experimental tests. Subsequently, the uncertainty associated with the numerical integration of thrust measurements using the trapezoidal method was addressed. While this method is simple and efficient, it can introduce additional uncertainties due to data discretization. By propagating the uncertainties of thrust measurements throughout the integration process, it was possible to quantify the uncertainty in the calculation of total impulse in 0.0252 Ns (0.0070%). Figure 7: Filtered signal. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Type of Filter** & **Total Impulse** & **Difference** \\ \hline Unfiltered & 354.894 N.s & \\ Filtered & 354.752 N.s & 0.142 N.s (0.04%) \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Comparison of numerical integration in unfiltered and filtered signals. Furthermore, the analysis of percentual uncertainty in the numerical integration of the collected data yielded similar results to those of direct thrust measurement, owing to the substantial number of data points sampled during the experiment. This study underscores the importance of rigorous uncertainty analysis in validating experimental results and improving measurement and analysis processes. Integrating uncertainty calculations from thrust measurements and numerical integration offers a comprehensive view of rocket motor test accuracy. This study underscores the importance of rigorous uncertainty analysis to validate experimental results and guide improvements in measurement and analysis processes. Ultimately, a verification was carried out to determine whether the oscillation of the measured signal could affect the uncertainty in the numerical integration used to calculate total impulse, especially in static rocket motor tests, where mechanical vibrations, structural resonance, and electronic noise are critical factors. These factors could distort thrust measurements over time, compromising the accuracy of the total impulse calculation. The results obtained after applying digital filters and numerically integrating the thrust signals showed that the variation in the total impulse calculation was minimal. The difference was below 0.04% of the total impulse value, indicating that the signal oscillations had a negligible impact. The detailed methodology for evaluating measurement uncertainty presented in this article was developed to ensure metrological reliability in rocket motor testing. The approach adopted for uncertainty propagation and digital signal analysis is sufficiently robust to be replicated in other experimental scenarios or similar measurement chains. This characteristic makes the method applicable to different laboratories and contexts, contributing to the standardization and improvement of data quality in propulsion-related studies. Furthermore, the results indicated that the uncertainties associated with thrust measurement and total impulse calculation, in the case under study, do not significantly affect the rocket's overall performance. The variations found are within acceptable limits, ensuring that the measured values are suitable for planning, developing, and validating rocket motors. Thus, the analysis reinforces the data's reliability and relevance for practical applications in the aerospace field.