UWB Object Location System Using Zone-Based Reference Tags
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Solution Overview
Problem
Existing RF object location systems face challenges in accurately determining object position in large, multipath, and noisy environments due to signal dispersion in cables, clock synchronization issues, and limited coverage caused by obstructions, leading to reduced accuracy and potential dead zones.
Innovation Solution
A system utilizing multiple ultra-wideband (UWB) reference tags and a zone-based approach with shared receivers and a common clock source to determine timing offsets and improve position accuracy, allowing for greater coverage and scalability while maintaining high precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cable connections are used to relay RF signals to a central measuring unit, then signal transmission is achieved, but signal dispersion degrades arrival time detection accuracy
Solution Approach 1:
The patent extracts the signal processing function from the cable medium and relocates it to the monitoring stations themselves. Each monitoring station performs digital signal processing locally to determine arrival times, eliminating the need to transmit analog RF signals through dispersive cables to a central unit. This extraction of the processing function from the transmission medium resolves the contradiction by maintaining reliable cable connections while eliminating signal dispersion effects on measurement precision.
Solution Approach 2:
The patent replaces the analog RF signal transmission mechanism with a digital data transmission mechanism. Instead of relaying analog RF signals through cables where dispersion occurs, the system converts signals to digital representations at the monitoring stations and transmits digital data, which is immune to dispersion effects. This substitution resolves the contradiction between reliable analog signal transmission and precise arrival time measurement.
2Ease of operation
If independent clock sources are used at each monitoring station, then system autonomy is achieved, but timing reference drift degrades position measurement accuracy
Solution Approach 1:
The patent implements a feedback mechanism where a timing reference signal is distributed from a central source to all monitoring stations. Each station's independent clock is continuously corrected by comparing its timing reference against the central reference and adjusting accordingly. This feedback loop maintains synchronization across all stations, resolving the contradiction between system autonomy and measurement precision by allowing local operation while ensuring coordinated timing.
Solution Approach 2:
The patent creates a universal timing reference system where a single central clock source serves all monitoring stations simultaneously. This universal reference provides a common time baseline for all measurements across the entire monitoring network, enabling both autonomous operation at each station and consistent position measurement accuracy across the system.
3Device complexity
If a single reference transmitter is used, then system simplicity is maintained, but coverage is limited by obstructions creating dead zones
Solution Approach 1:
The patent segments the monitoring area into multiple zones, each with its own reference transmitter. This segmentation allows each reference transmitter to serve a specific zone, eliminating dead zones caused by obstructions that would affect a single omnibus reference transmitter. The system maintains relative simplicity by organizing multiple transmitters in a structured zonal configuration rather than using a complex distributed network.
Solution Approach 2:
The patent extends the system from a single-point reference model to a multi-point distributed reference model, adding spatial dimensionality to the reference transmitter arrangement. By placing reference transmitters at multiple locations throughout the monitoring area, the system achieves comprehensive coverage without sacrificing operational simplicity, as each zone can be independently configured and managed.
4Area of stationary object
If multiple monitoring stations are deployed to overcome obstructions, then coverage is improved, but system complexity and cost increase
Solution Approach 1:
The patent merges multiple monitoring stations into a coordinated network that shares a common timing reference and centralized processing architecture. By combining the timing reference function at a central source and the processing function in a centralized unit, the system achieves extensive coverage through multiple stations while minimizing overall complexity through functional integration and standardization.
Solution Approach 2:
The patent performs preliminary synchronization of all monitoring stations to a common timing reference before deployment. This preliminary action ensures that all stations are pre-configured with accurate timing information, eliminating the need for complex real-time synchronization protocols during operation and reducing system complexity while enabling comprehensive coverage.
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
The system achieves highly accurate position measurements (+/â1 foot or better) with improved coverage and scalability, overcoming signal blockages and obstructions, and maintaining high precision in large areas.
Implementation Method 1
A common clock source synchronizes the frequency of cyclic timers of each receiver to produce phase offsets between cyclic timers of the different receivers of the group
Implementation Method 2
A reference tag associated with each receiver group transmits an RF reference signal (which may also be an ultra wideband signal) from a known location to enable determination of timing offsets
Implementation Method 3
A cyclic timer associated with each receiver detects an arrival time of an RF signal
Implementation Method 4
A processing hub in communication with the receivers determines the position of the object according to timing offsets and time differences of arrival of RF signals transmitted by the object tag
Data Source
AI summary
An ultra wideband (UWB) or short-pulse RF system is disclosed that can be used to precisely locate or track objects (such as personnel, equipment, assets, etc.) in real-time in an arbitrarily large, physically connected or disconnected, multipath and/or noisy environment. A system implementation includes multiple zones or groups of receivers that receives RF signals transmitted by one or more timing reference tags and one or more objects having associated object tags. Each zone or group may share a common receiver. By combining a multiple reference tag system with a virtual group of receivers, i.e., a zoning technique or system, a cost-effective system can be provided that offers scalability and flexibility to monitor a significantly expanded coverage area.