Directed Sound Beam Drone Noise Cancellation for Stealth Surveillance
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Solution Overview
Problem
Drones used for surveillance face challenges in remaining undetected due to their noise, which can alert targets and compromise their ability to effectively observe or communicate without being noticed.
Innovation Solution
A drone equipped with a sound system that actively cancels its own noise and can emit directed sound beams to cancel noise directed at targets, while also receiving and processing sound waves to extract voice messages, using a combination of noise receivers, cameras, distance measurers, and processors to analyze and adjust the sound beams based on detected noise and target location.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the drone uses a motor to power and move, then the drone achieves mobility and flight capability, but the motor generates noise that alerts targets and compromises surveillance effectiveness
Solution Approach 1:
The patent applies active noise cancellation technology where the drone's own motor noise is detected by microphones and then inverted phase-wise to create canceling sound waves. The processed canceling noise is emitted through speakers to neutralize the original motor noise, converting the harmful noise into a beneficial silence that maintains surveillance stealth while preserving motor-driven mobility
2Ease of operation
If the drone emits sound to communicate or attract attention, then the drone achieves communication capability, but the sound reveals the drone's location and compromises stealth
Solution Approach 1:
The patent employs directional sound beam technology that focuses acoustic energy into a narrow, targeted beam rather than omnidirectional emission. The sound beam is precisely directed toward the target area, providing localized communication or attention-grabbing capability while minimizing sound propagation in other directions, thereby maintaining stealth in areas outside the beam path
Solution Approach 2:
The system preemptively applies noise cancellation to the communication sound beams by detecting the intended communication sound, generating inverse phase canceling waves, and emitting them through the directional speaker. This preliminary anti-action ensures that even when communication sounds are emitted, the net acoustic signature remains minimal, preventing target alertness while maintaining communication functionality
3Object-generated harmful factors
If the drone uses active noise cancellation to reduce motor noise, then the drone achieves stealth, but the noise cancellation system adds device complexity
Solution Approach 1:
The patent integrates the noise cancellation system with the existing communication sound system, where the same directional speaker array serves dual purposes: emitting communication sounds and projecting noise canceling waves. The microphones and processors are shared between both functions, allowing the system to achieve stealth through active noise cancellation without proportionally increasing overall device complexity, as components serve multiple functions
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
Enables the drone to remain quiet and unnoticed while surveilling, allowing for effective visual and auditory data collection, including the extraction of human voice messages from the target, enhancing its operational stealth and effectiveness.
Implementation Method 1
emit a sound beam that is directed to a particular direction... configured to actively cancel at least a portion of the detected noise directed at the target
Data Source
AI summary
A drone includes a motor, a noise receiver, a camera, a distance measurer, and a directed sound beam generator. The noise receiver is configured to detect a noise caused by the motor. The camera is configured to capture an image of an area when the drone is in the air. The distance measurer is configured to measure a distance between the drone and a particular point in the captured image. The directed sound beam generator is configured to emit a sound beam that is directed to a particular direction. The drone further includes a processor configured to analyze the detected noise to determine a frequency spectrum of the detected noise. The processor is further configured to analyze the captured image to identify a target, and cause the directed sound beam generator to emit a sound beam to actively cancel at least a portion of the noise directed to the target.