Redundant Chronograph with Collocated Start and Stop Planes
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Solution Overview
Problem
Current ballistic chronograph systems face measurement uncertainties due to differences in spacing and positioning of light screens, leading to variations in estimated projectile velocities, which do not meet the stringent requirements of modern standards like NIJ-0101.07 and ASTM E3062-20 for accurate ballistic performance evaluation.
Innovation Solution
A chronograph system with a novel configuration of collocated start and stop screens, where multiple detector arrays are arranged in redundant pairs at entrance and exit planes, ensuring equal spacing and reduced measurement uncertainty, thereby simplifying the arrangement and improving velocity measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional light screen configurations with different spacing are used, then the chronograph can measure projectile velocity, but measurement uncertainty increases due to variations in estimated velocity
Solution Approach 1:
The system divides the measurement function into multiple independent detector arrays arranged in redundant pairs at entrance and exit planes. Each pair independently measures velocity, and the results are combined to reduce uncertainty. This segmentation allows for redundant measurements that converge on a more accurate velocity estimate.
Solution Approach 2:
Multiple detector arrays are merged into a unified chronograph system with collocated start and stop screens. The entrance planes of all chronographs are coplanar and the exit planes are coplanar, creating a combined measurement system that leverages multiple independent measurements to reduce overall uncertainty.
2Reliability
If multiple independent sets of instrumentation are used to meet test standards, then velocity measurement reliability improves, but device complexity increases
Solution Approach 1:
Multiple independent sets of instrumentation are merged into a single integrated chronograph system. The detector arrays are arranged in redundant pairs that share common start and stop screens, allowing two or more independent velocity measurements to be obtained from one unified system rather than requiring separate complete instrumentation sets.
Solution Approach 2:
The chronograph system is designed to perform multiple functions simultaneously - it can provide multiple independent velocity measurements, satisfy different test standards (NIJ-0101.07, ASTM E3062-20), and reduce measurement uncertainty all within a single device configuration.
3Measurement precision
If light screens are positioned at different locations, then the chronograph can capture projectile velocity data, but measurement uncertainty increases due to spacing differences
Solution Approach 1:
All entrance planes are positioned at the same location (collocated) and all exit planes are positioned at the same location (collocated). This creates equipotential measurement conditions where each detector array pair measures over the same distance, eliminating uncertainty related to varying spacing between light screens.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration significantly reduces measurement uncertainty, achieving average combined instrumental uncertainty of approximately 0.96 m/s or less, meeting the specified tolerance limits and enhancing the accuracy of projectile velocity measurements.
Implementation Method 1
These sensors are typically equipped with photodetectors or infrared sensors. When a projectile passes through the sensors, it interrupts the light beams or triggers the sensors in some way.
Implementation Method 2
The chronograph measures the time it takes for the projectile to travel between the sensors.
Implementation Method 3
These chronographs emit radar waves, and the Doppler shift in the reflected waves is analyzed to determine the speed of the projectile.
Data Source
AI summary
A chronograph system has with a set of co-located start planes and a set of co-located stop planes spaced from the start planes, thereby minimizing measurement differences.