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Practical Estimation of Uncertainty in Test Velocity Measurements Using Optical Screens



Michael A. Riley, Kirk D. Rice, Nicholas G. Paulter Jr.


The velocity of the test projectile is one of the critical measurements when testing armor and other protective equipment for ballistic resistance. Good laboratory practice requires estimating the uncertainty of these measurements, and understanding the sources of that uncertainty is essential to ensuring that test results are correct and repeatable. Velocity measurements, however, are particularly complicated, because they require two independent measurements: the time of flight of the projectile between two measurement points and distance between those points. These measurements may appear to be relatively simple to make, but nuances in how the measurements are made and small variations from ideal test conditions can significantly influence the resulting velocity measurement. In addition, the uncertainty of the velocity measurement will be dependent on both the measurement equipment and how that equipment is used. This work is focused on understanding what factors significantly influence the uncertainty of projectile velocity measurements made with commercial systems of the types that are common in test laboratories. Common sources of measurement errors are considered and their likely influence on the estimated uncertainty is evaluated. The results are intended to provide laboratory personnel with a practical framework in which they can determine what factors they need to consider when assessing the uncertainty of their velocity measurements.
Proceedings Title
Personal Armour Systems Symposium
Conference Dates
October 1-5, 2018
Conference Location
Washington, DC, US


Velocity Measurement, armor testing


Riley, M. , Rice, K. and Paulter Jr., N. (2018), Practical Estimation of Uncertainty in Test Velocity Measurements Using Optical Screens, Personal Armour Systems Symposium, Washington, DC, US (Accessed April 20, 2024)
Created October 1, 2018, Updated October 12, 2022