Audio Signal Indoor Navigation Using Digital Watermarks
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Solution Overview
Problem
Traditional GPS technologies are not effective or practical in indoor environments, and existing audio-based positioning systems face challenges with signal interference, complexity, and cost-effectiveness, particularly in integrating with existing audio equipment and mobile devices.
Innovation Solution
The use of digital watermarks embedded in audio signals to convey positioning information, utilizing robust encoding techniques and signal processing methods to overcome interference and complexity, allowing for accurate location determination using existing audio equipment and mobile device microphones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional GPS technologies are used for positioning, then outdoor location accuracy is improved, but indoor positioning effectiveness deteriorates
Solution Approach 1:
The patent replaces satellite-based GPS (electromagnetic system) with audio-based positioning (acoustic system). Mobile devices use microphones to capture audio signals from nearby audio sources, and the system determines position based on audio signal characteristics rather than satellite signals, enabling effective indoor positioning where GPS fails.
2Reliability
If audio-based positioning systems are implemented, then indoor positioning capability is improved, but signal interference increases
Solution Approach 1:
The patent extracts and utilizes distinctive audio characteristics (such as audio fingerprints or unique signal features) from audio sources to identify and locate them. By focusing on these extracted characteristics rather than the entire audio signal, the system can distinguish target audio sources from interfering background sounds and noise.
Solution Approach 2:
The system continuously monitors audio signals and adjusts positioning calculations based on received signal strength indicators (RSSI) and audio characteristic matching. This feedback mechanism allows the system to compensate for varying environmental conditions and interference levels in real-time.
3Measurement precision
If complex positioning algorithms are used to overcome interference, then positioning accuracy is improved, but device complexity increases
Solution Approach 1:
The patent uses received signal strength indicator (RSSI) measurements from audio sources to determine position. This partial approach (using only signal strength rather than full audio analysis) provides sufficient positioning accuracy for many applications while keeping computational complexity low and processing requirements manageable.
Solution Approach 2:
The system utilizes audio characteristics and signal strength that are naturally present in the environment, requiring minimal additional processing. The mobile device's existing microphone and processor are sufficient for capturing and analyzing audio signals, eliminating the need for complex external equipment or intensive computational resources.
4Ease of manufacture
If existing audio equipment is utilized for positioning, then cost-effectiveness is improved, but integration complexity increases
Solution Approach 1:
The patent makes existing audio equipment (audio sources, microphones) serve dual purposes: their original audio function plus positioning function. Audio sources continue to play audio while simultaneously transmitting positioning signals, and mobile device microphones continue to capture audio while also detecting positioning signals, eliminating the need for separate positioning infrastructure.
Solution Approach 2:
Existing audio equipment serves its own positioning function without requiring additional components or systems. Audio sources and microphones use their inherent capabilities to provide positioning information, and the mobile device's existing processor handles both audio processing and positioning calculations, minimizing integration complexity.
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 reliable and cost-effective indoor navigation and location-based services by accurately determining the position of mobile devices using audio signals, even in noisy environments, without degrading audio quality or requiring complex equipment.
Implementation Method 1
A mobile device determines its position based on identification of an audio signal captured using a microphone of the mobile device
Data Source
AI summary
Mobile device positioning employs various forms of audio signal structures and detection methodologies. In one method, detection of an audio signal from a first source enables construction of a signal to facilitate detection of an audio signal from another source. Signals detected from these sources enable positioning of the mobile device receiving those signals. Another method forms audio signals transmitted from audio sources so that they have parts that add constructively and parts that differentiate the sources to enable positioning. Another audio signal based positioning method adaptively switches among positioning methods so that positioning remains operative as a mobile device moves toward and away from the sources. Another method tracks positioning history, evaluates it for errors and performs error mitigation to improve accuracy. Various other positioning technologies are detailed as well.