Audio Watermark Indoor Navigation System
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Solution Overview
Problem
Traditional GPS technologies are not effective or practical in certain applications, such as indoor navigation, due to signal interference and complexity, and existing audio-based positioning systems face challenges in integrating with consumer audio equipment and maintaining accuracy in noisy environments.
Innovation Solution
The use of digital watermarks embedded in audio signals to convey positioning information, utilizing robust encoding techniques and signal processing methods to differentiate sources and calculate the position of a mobile device, even in the presence of ambient noise and echoes, by integrating with existing audio playback systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional GPS technologies are used for positioning, then positioning can be achieved in outdoor environments, but the system becomes ineffective and impractical in indoor environments due to signal interference
Solution Approach 1:
The patent replaces the radio frequency-based GPS system with an acoustic-based positioning system using audio sources and microphones. This substitution allows the system to function effectively in indoor environments where GPS signals are blocked, as acoustic waves can penetrate building structures and propagate through indoor spaces reliably.
Solution Approach 2:
The patent changes the fundamental parameter of the positioning system from electromagnetic wave frequency (GPS) to acoustic wave frequency (audio). This parameter change enables the system to operate in environments where the original parameter (RF signals) is ineffective, specifically indoor spaces with structural obstructions.
2Adaptability or versatility
If audio-based positioning systems are implemented, then indoor positioning becomes feasible, but the system faces challenges in maintaining accuracy in noisy environments with ambient noise and echoes
Solution Approach 1:
The patent segments the audio signal processing into distinct stages: signal capture from multiple microphones, separation of desired audio sources from ambient noise using beamforming or source separation algorithms, extraction of positioning-relevant features, and calculation of position coordinates. This segmentation allows each stage to be optimized independently for accuracy.
Solution Approach 2:
The patent introduces intermediary processing steps between audio capture and position calculation, including signal filtering, noise reduction algorithms, and feature extraction intermediaries. These intermediaries process the raw audio signals to enhance the signal-to-noise ratio and extract robust positioning features even in noisy environments.
3Measurement precision
If digital watermarks are embedded in audio signals for positioning information, then accurate source differentiation is achieved, but the system complexity increases
Solution Approach 1:
The patent implements digital watermarks that serve multiple functions simultaneously: they encode source identification information for differentiation, provide synchronization signals for timing analysis, and can carry additional metadata about the audio source. This multi-functionality reduces the need for separate signaling mechanisms and justifies the processing complexity through consolidated functionality.
Solution Approach 2:
The patent uses computationally efficient watermark detection algorithms that can be implemented as lightweight software modules on mobile devices. These algorithms are designed to be fast and resource-efficient, allowing complex source differentiation without requiring expensive hardware upgrades or excessive processing power.
4Ease of manufacture
If audio signals are used for positioning, then existing audio playback systems can be integrated, but signal interference from other audio sources and ambient noise degrades positioning accuracy
Solution Approach 1:
The patent leverages the continuous playback of audio signals from existing audio systems, which provides a persistent and stable reference signal for positioning. The continuous nature of the audio signal allows for ongoing tracking and refinement of position estimates, and enables the use of temporal correlation techniques to distinguish the intended audio source from intermittent noise or other audio sources.
Data Source
AI summary
An audio playback system receives digitally watermarked audio programming and distributes it to audio speakers in a venue, enabling a variety of location and product dependent services to be delivered to mobile devices in the venue. Mobile devices sense audio from speakers and decode digital identifying information, including characteristics to distinguish audio sources. The mobile device communicates with a networked computer to provide the identifying information, which in turn, triggers an alert for output on the mobile device.