E-field Projectile Detection via Electric Potential Sensors
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Solution Overview
Problem
Current acoustic-based projectile detection systems face challenges in accurately detecting subsonic or silenced projectiles, multiple consecutive shots, and are prone to false alarms due to reverberation, multipath propagation, and high acoustic noise, especially in complex environments.
Innovation Solution
An E-field based detection system utilizing multiple electric potential sensors and a noise cancellation algorithm to determine the direction and speed of projectiles, combined with acoustic sensors to enhance detection capabilities and reduce false alarms, including the use of a bi-modal E-field and acoustic system for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If acoustic sensor based detection systems are used, then supersonic projectiles can be detected, but the system becomes saturated or degraded by reverberation, multipath propagation, high levels of acoustic noise, and vibration
Solution Approach 1:
The patent introduces E-field sensors as an intermediary detection mechanism that detects the electric charge on projectiles through electromagnetic field interaction rather than acoustic wave propagation. This mediator approach bypasses the harmful acoustic environment (reverberation, multipath, noise) by using a different physical domain (electric field) to detect the same target (charged projectile), thereby resolving the contradiction between detection reliability and environmental interference.
2Adaptability or versatility
If acoustic sensing based systems are used, then supersonic projectiles can be detected, but the system does not work for subsonic or silenced projectiles
Solution Approach 1:
The patent replaces the acoustic sensing mechanism (mechanical wave detection) with E-field sensing (electromagnetic field detection). This substitution allows the system to detect projectiles through their electric charge regardless of their speed or noise characteristics, enabling detection of both supersonic and subsonic/silenced projectiles and thus resolving the contradiction between adaptability to different projectile types and reliable detection.
3Productivity
If acoustic-based systems are used, then projectile detection is possible, but the system has difficulties detecting multiple consecutive shots from a single or multiple shooters if these projectiles come in a very short period of time
Solution Approach 1:
The patent employs periodic sampling of the E-field signals at high rates, allowing the system to capture and distinguish multiple consecutive projectile events that occur in rapid succession. The periodic E-field measurements provide sufficient temporal resolution to separate closely spaced shots, resolving the contradiction between detecting multiple consecutive shots (productivity) and the time loss or ambiguity in resolving them.
4Adaptability or versatility
If E-field sensors are used alone, then subsonic and supersonic projectiles can be detected, but the false-alarm rate is higher compared to acoustic-enabled detection
Solution Approach 1:
The patent merges E-field sensing and acoustic sensing into a bi-modal detection system. The E-field channel provides detection capability for both supersonic and subsonic projectiles, while the acoustic channel provides shockwave detection for supersonic projectiles. By fusing these two independent detection channels, the system achieves versatile detection across all projectile types while using the acoustic shockwave signature as a verification mechanism to reduce false alarms, thus resolving the contradiction between adaptability and reliability.
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 E-field based system effectively detects both supersonic and subsonic projectiles with a lower false-alarm rate, capable of identifying multiple consecutive shots within a short time period, and improves detection accuracy in complex environments by integrating electric potential and acoustic sensors.
Implementation Method 1
Projectiles, including bullets, passing through open-air regions carry an electric charge from the initial explosive combustion and triboelectric charging that occurs when the object passes through open-air regions. This charge can be sensed by an electric field (E-field) sensor or electric potential sensor.
Implementation Method 2
supersonic projectiles with a much lower false-alarm rate
Data Source
AI summary
A system and method use electric potential measurements to locate and characterize passing projectiles, including advanced data processing methods to reject background noise and determine projectile speed, preferentially incorporating acoustic-based measurements to provide additional benefits.