Indoor Asset Localization with Sparse Antennae and TOA
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Solution Overview
Problem
Existing indoor asset tracking systems face challenges in achieving high-precision localization with limited antenna density and addressing ambiguity from multi-frequency signal emission, leading to increased infrastructure costs and reduced accuracy.
Innovation Solution
A two-stage system comprising a real-time locating system (RTLS) for approximate location and a locator device for precise indication, using a decentralized approach with fewer antennae and leveraging multiple communication technologies to enhance accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dense array of receiving antennae is deployed to achieve high-precision localization (3-5 metres or less accuracy), then localization accuracy is improved, but infrastructure cost and device complexity increase substantially
Solution Approach 1:
The patent segments the localization task into two distinct stages: a first stage using a RTLS with sparse antenna deployment for approximate location determination, and a second stage using a locator device for precise location indication. This segmentation allows the system to achieve high overall precision without requiring dense antenna coverage throughout the entire environment.
Solution Approach 2:
The locator device acts as an intermediary between the sparse RTLS infrastructure and the user, bridging the gap between approximate RTLS location data and the need for precise location indication. The locator device receives signals from both the RTLS antennae and the asset transmitter, combining this information to provide meter-level precision without requiring dense RTLS antenna deployment.
2Reliability
If multiple radio channels are used for signal transmission to improve coverage and reliability, then system robustness is improved, but RSSI measurement accuracy deteriorates due to frequency-dependent propagation variations
Solution Approach 1:
The patent changes the parameter being measured from RSSI (which is frequency-dependent and unreliable across multiple channels) to TOA (time of arrival), which is frequency-independent and provides consistent measurements across all radio channels. This parameter change allows the system to maintain reliable multi-channel operation without sacrificing measurement accuracy.
Solution Approach 2:
The patent extracts the timing information (TOA) from the radio signals while discarding the RSSI measurements that are corrupted by frequency-dependent propagation effects. By focusing solely on the time of arrival parameter, the system achieves accurate location determination that is independent of the radio channel or frequency used for transmission.
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 metre-level precision asset tracking with reduced infrastructure costs and improved accuracy by providing precise location indications using a two-stage process.
Implementation Method 1
radio signals over N channels, wherein N is greater than one
Implementation Method 2
measuring a time of arrival of the signal
Data Source
AI summary
Asset localization solutions are provided. They allow a signal-emitting device to be reached an accuracy of less than one metre in an indoor environment and in nearby associated locations with a small number of antennae. The solution is technologically agnostic with respect to the type of receiver and/or transmitter used. A system for assisting a user in locating an asset including a transmitter that emits a signal includes a real time locating system (RTLS) and a locator device. The RTLS provides an approximate location of the asset based on a first signal characteristic measured by its receivers. The locator device provides a more precise indication based on a second signal characteristic measured by its receivers and conveys it to the user through its output devices.