Acoustic Ranging for Indoor Terminal Positioning
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Solution Overview
Problem
Existing location determination systems for wireless communication terminals, such as GNSS, face challenges in accuracy and reliability, especially indoors where GNSS signals are weak or unavailable, leading to failures in over 50% of emergency calls, prompting the need for improved terrestrial positioning systems that require significant infrastructure investment.
Innovation Solution
Wireless communication terminals and network nodes that record and process sound signals to determine location, using privacy-protected audio segments and timestamps, correlating these with other terminals to identify sound sources or terminal locations, even in environments with weak RF signaling, and combining with GNSS data for enhanced accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GNSS receivers are used for location determination, then location data can be obtained in open environments, but the system fails in over 50% of cases when terminals are inside buildings due to weak or unavailable GNSS signals
Solution Approach 1:
The patent introduces sound recordings as an intermediary medium for location determination. Instead of relying directly on GNSS signals that are blocked by buildings, the system uses acoustic signals (which can penetrate buildings) as a mediator to establish location. Multiple terminals record the same sound event, and the network correlates these recordings to determine terminal positions, effectively bypassing the signal blockage problem.
Solution Approach 2:
The patent replaces the electromagnetic-based GNSS system with an acoustic-based positioning system. By substituting radio frequency signals with sound wave propagation, the system overcomes the limitation of electromagnetic signal blockage by building structures, as acoustic waves can more effectively penetrate and propagate through indoor environments.
2Measurement precision
If Terrestrial Beacon Systems are deployed to improve indoor positioning, then location accuracy can be enhanced, but significant infrastructure investment is required
Solution Approach 1:
The patent makes existing terminals multi-functional by enabling them to serve as both communication devices and acoustic sensors for positioning. Instead of deploying dedicated beacon infrastructure, the system utilizes the microphones and processors that are already present in smartphones and other terminals, allowing these devices to perform dual functions of communication and acoustic-based location determination.
Solution Approach 2:
The system enables terminals to determine their own locations using their built-in microphones and processing capabilities. Each terminal independently records sound events and transmits the recordings to the network, which then correlates the data to determine positions. This self-service approach eliminates the need for external beacon infrastructure, as the terminals themselves provide the sensing and processing functions.
3Measurement precision
If sound recordings from multiple terminals are correlated to determine location, then indoor positioning accuracy is improved, but processing complexity increases
Solution Approach 1:
The patent divides the location determination task into separate processing stages: (1) individual terminals independently record and timestamp sound events, (2) the network receives and segments these recordings, (3) the network correlates the segmented recordings to determine relative positions. This segmentation distributes the processing complexity across multiple independent terminals rather than requiring one complex centralized processor.
Solution Approach 2:
The system performs preliminary actions at the terminal level before network processing. Each terminal pre-records sound events with precise timestamps and transmits them to the network. This preliminary recording and timing synchronization at the source reduces the complexity of network-side processing, as the heavy lifting of data collection and initial processing is already completed by the distributed terminals.
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
This method effectively determines the location of wireless communication terminals and sound sources indoors by processing sound recordings, providing accurate location data while protecting privacy and reducing the need for new infrastructure, thereby improving emergency call reliability and location services.
Implementation Method 1
a microphone, configured to sense sound
Implementation Method 2
a location service client of a network node that determines location of a sound source and/or a location of the electronic communications terminal based on correlating the sampled audio segment and other sampled audio segments of the sound received from other electronic communications terminals
Data Source
AI summary
An electronic communications terminal records in a memory a sampled audio segment of sound sensed by a micro-phone. A time stamp associated with timing of the recording of the sampled audio segment is determined and stored in the memory associated with the sampled audio segment. The sampled audio segment and the time stamp are transmitted through a network interface toward a location service client of a network node that determines location of the electronic communications terminal based on correlating the sampled audio segment and other sampled audio segments of the sound received from other electronic communications terminals. A related network node and corresponding methods by terminals and network nodes are disclosed.