Ballistic Velocity Measurement Using Diffused Laser Gates
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Solution Overview
Problem
Existing ballistic projectile velocity measurement systems face challenges due to variable illumination levels from incandescent or ambient light sources, leading to inconsistent detection and potential misreadings caused by reflected light, which complicates the accurate calculation of projectile velocity.
Innovation Solution
A measurement apparatus using a diffuser to create a wall of light from a laser source, allowing a sensor array to detect perturbations caused by projectiles, and a chronograph processor to calculate velocity based on the time difference between detections at two gates, providing a consistent and accurate measurement of projectile velocity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ambient light or incandescent light sources are used for illumination, then the photodetectors can detect projectile passage, but the illumination level varies due to environmental conditions, dust, aging, and reflected light causing inconsistent detection
Solution Approach 1:
The patent changes the illumination source from ambient or incandescent light to a laser source with fixed wavelength, and introduces a diffuser to create a uniform wall of light. This parameter change ensures constant illumination intensity that is not affected by environmental conditions, dust, or aging, thereby improving detection consistency while maintaining illumination stability.
Solution Approach 2:
The patent introduces a diffuser as an intermediary element between the laser source and the detection area. The diffuser creates a uniform wall of light that eliminates direct light paths and reflected light issues, serving as a mediator that stabilizes illumination while enabling reliable projectile detection through the gate.
2Object-affected harmful factors
If an optical slit is used to restrict extraneous light, then reflected light is reduced, but the illumination level becomes highly variable depending on sky conditions and viewing angle
Solution Approach 1:
The patent replaces the optical slit with a diffuser and laser source combination. This parameter change eliminates the need to restrict light paths while creating a uniform illumination field that is independent of sky conditions or viewing angles, simultaneously reducing reflected light interference and eliminating illumination variability.
3Illumination intensity
If the photodetector receives direct light from the source, then the light level is higher, but reflected light from the projectile can cancel the shadow and cause misreadings
Solution Approach 1:
The patent introduces a diffuser as an intermediary that transforms the direct laser beam into a uniform wall of light. This eliminates direct light paths that could be reflected by the projectile, while maintaining high light levels through the diffused illumination. The result is accurate velocity measurement without shadow cancellation errors.
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
The system effectively mitigates the issues of variable illumination and reflected light, ensuring accurate and reliable velocity calculations by using a diffused light source and sensor array to detect projectile perturbations, enabling precise velocity determination.
Implementation Method 1
a diffuser positioned between the laser and the arcuate arm, the diffuser being configured to diffuse the laser light emitting from the laser over a diffusion angle to create a wall of light
Implementation Method 2
a sensor array comprising a plurality of laser light sensors housed within the arcuate arm and configured to receive beams of diffused laser light emitted from the laser through the diffuser, the sensor array being configured to register perturbances in the wall of light caused by a ballistic projectile
Data Source
AI summary
The present disclosure relates to a ballistic projectile velocity measurement apparatus that senses and records the times in which a projectile travels through two vertical planes represented by two sensor gates which are spaced horizontally from each other. The sensor gates each utilize an LED laser that emits a laser light through a diffuser along a diffusion angle into a plurality of laser light sensors to create a wall of laser light, and the sensor gates register a break in the wall of light when a ballistic projectile obstructs the light received by at least one laser light sensor. The ballistics apparatus then determines the velocity of the projectile based on the distance between the two gates and difference in time between the two plane-breaking events.