Partially Synchronized RF Multilateration for Indoor Positioning
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Solution Overview
Problem
Conventional RF-based location-finding systems face inaccuracies in indoor environments due to lack of precise time synchronization and errors in antenna position databases, failing to meet the stringent accuracy requirements of Real Time Locating Service (RTLS) and Location Based Services (LBS).
Innovation Solution
The implementation of a partially synchronized RF-based tracking and locating system using software-defined radio and digital signal processing, which employs clusters of precisely time-synchronized receivers and transmitters, allowing for accurate location determination in cellular networks and other wireless systems without requiring inter-cluster synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complete and precise time synchronization of all receivers and transmitters to a single common reference time is implemented, then location accuracy is improved, but system complexity and cost increase
Solution Approach 1:
The system divides the network into multiple clusters, where receivers and transmitters within each cluster are time-synchronized to a common reference, but inter-cluster synchronization is not required. This segmentation allows location determination to be performed independently within each cluster, reducing overall system complexity while maintaining accurate location finding capability.
Solution Approach 2:
Instead of requiring complete synchronization across the entire network, the system implements partial synchronization only within local clusters. This partial action is sufficient to achieve accurate location determination for devices within each cluster, avoiding the excessive complexity of full network-wide synchronization.
2Measurement precision
If all receivers and transmitters are time-synchronized to a single common reference time, then location accuracy is improved, but cost increases
Solution Approach 1:
By segmenting the network into independent clusters with local time synchronization, the system reduces the number of synchronized devices needed from the total network size to only cluster members. This significantly reduces hardware costs and deployment complexity while maintaining location accuracy within each cluster.
Solution Approach 2:
The system performs partial synchronization only where needed (within clusters) rather than across the entire network. This partial approach achieves sufficient location accuracy at a fraction of the cost of complete network-wide synchronization.
3Device complexity
If conventional multilateration/trilateration methods are used with time synchronization errors, then system complexity is reduced, but location accuracy deteriorates
Solution Approach 1:
The patent segments the network into clusters where local time synchronization eliminates synchronization errors within each cluster. This allows conventional multilateration methods to be used without accuracy degradation, as the synchronization problem is confined to small local groups rather than the entire network.
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 approach significantly enhances location accuracy, overcoming the limitations of conventional systems by providing precise positioning in challenging environments while reducing costs and complexity, and improving the operating range and battery life of tracking devices.
Implementation Method 1
the fundamental requirement for multilateration/trilateration based systems is the complete and precise time synchronization
Data Source
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AI summary
Systems and methods for determining a location of user equipment (UE) in a wireless system can comprise receiving reference signals via a location management unit (LMU) having two or more co-located channels, wherein the two or more co-located channels are tightly synchronized with each other and utilizing the received reference signals to calculate a location of the UE. Some systems may include multichannel synchronization with a standard deviation of less than or equal 10 ns. Some systems may include two LMUs, with each LMU having internal synchronization, or one LMU with tightly synchronized signals.