Shooting Target Sensor Array for Rapid Fire Impact Detection
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Solution Overview
Problem
Conventional shooting target systems using accelerometers or piezoelectric sensors for detecting bullet impacts are limited by high costs, fragility, and low accuracy, especially when dealing with rapid fire capabilities and varying ammunition calibers, leading to inaccurate impact location calculations.
Innovation Solution
A shooting target system featuring a dense array of inexpensive sensors on a ballistic plate, with a processor determining the impact location by identifying which sensors are activated within a limited time interval, using tunable voltage thresholds to differentiate between impact signals and residual vibrations, allowing for accurate detection of rapid fire and various ammunition types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If accelerometers are used as sensors to detect bullet impact, then impact location can be determined, but the system becomes expensive and the sensors are fragile
Solution Approach 1:
The patent replaces expensive accelerometers with inexpensive piezoelectric sensors that generate voltage signals when vibrated by bullet impacts. These sensors are designed to be replaceable and economical, allowing dense arrays to be deployed without prohibitive cost. The system accepts that sensors may need replacement but mitigates this through their low cost and standardized mounting.
Solution Approach 2:
The patent introduces a protective layer or mounting structure that positions the piezoelectric sensors away from the direct bullet impact zone while still allowing them to detect vibrations transmitted through the target material. This intermediary positioning protects fragile sensors from direct bullet strikes while maintaining their ability to detect impact locations through vibration waves.
2Reliability
If accelerometers are positioned away from the central aim point to protect them, then sensor destruction is reduced, but impact location calculation accuracy decreases
Solution Approach 1:
The patent transitions from measuring impact intensity (scalar) with accelerometers to measuring vibration wave arrival times across multiple dimensions with piezoelectric sensors. By using time difference of arrival (TDOA) calculations based on when vibration waves reach different sensor positions, the system can accurately locate impacts even when sensors are positioned in a protective configuration rather than directly at the impact point.
Solution Approach 2:
The patent replaces the mechanical accelerometer system that directly measures impact force with an electrical piezoelectric sensor system that converts mechanical vibrations into electrical signals. This substitution allows for more flexible sensor positioning and protects the sensors while maintaining measurement capability through the piezoelectric effect, which detects vibrations transmitted through the target material rather than requiring direct impact measurement.
3Measurement precision
If piezoelectric sensors are used with TDOA to determine impact location, then impact location can be calculated, but the location calculation is prone to very low accuracy due to wave interference
Solution Approach 1:
The patent implements dynamic threshold adjustment and real-time signal processing that adapts to varying vibration patterns. The system continuously monitors signal characteristics and adjusts detection parameters to distinguish primary impact waves from secondary reflections and interference patterns, maintaining accurate detection despite wave interference effects.
Solution Approach 2:
The patent incorporates feedback mechanisms where the system analyzes detected vibration patterns and uses this information to refine subsequent detections. By comparing expected wave propagation patterns with actual sensor readings, the system can identify and compensate for interference effects, improving location calculation accuracy over time and across multiple detections.
4Measurement precision
If TDOA is used to determine impact location, then location can be calculated, but the wait time between shots is long (0.5 to 5 seconds)
Solution Approach 1:
The patent implements preliminary signal processing and continuous monitoring modes where sensors are always active and processing circuits are pre-configured. When an impact occurs, the system immediately captures and processes the vibration signals without waiting for a reset period, enabling rapid succession detections. The system prepares detection algorithms and signal processing pipelines in advance to minimize processing delays between shots.
Solution Approach 2:
The patent maintains continuous operation of sensors and signal processing circuits without interruption between shots. Unlike systems that require complete vibration dissipation and sensor reset, this system continuously monitors vibration patterns, allowing it to detect and process impacts in rapid succession. The continuous operation eliminates idle wait times and enables the system to handle high-rate fire scenarios where shots occur faster than traditional systems can reset.
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 provides accurate and rapid detection of bullet impacts, capable of handling high-frequency shooting with improved sensor protection and cost-effectiveness, enabling precise location calculation and enabling the use by a wider range of shooters.
Implementation Method 1
an array of sensors applied to cover a major central portion of the rear face of the plate, each sensor being responsive to vibration of the plate in response to a projectile strike to generate a strike signal
Data Source
AI summary
A shooting target system exhibiting a ballistic plate having a front face, capable of being struck by aimed projectiles, and an opposed rear face which is made to accept an array of sensors for the detection and transmittal of ballistic strike information. The array of sensors is applied to the opposed rear face and is made to cover a major portion of the rear face. Each sensor is responsive to discrete areas of vibration of the ballistic plate, resulting from a projectile strike, which generates a strike signal that is transmitted to a processor connected to each of the sensors. The processor determines which of the sensors is/are first activated by a projectile strike during a limited time interval and calculates the location of a projectile strike based on the location of the activated sensors and whether each sensor's input is above or below a preselected threshold.