Time-Slotted UWB Ranging for Precise Indoor Object Tracking
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Solution Overview
Problem
Conventional tracking systems struggle to accurately measure the distance between devices with precision in indoor environments due to limitations in time-of-flight measurement and reliance on high-energy radio signals or satellite-dependent GPS, which are ineffective in non-line-of-sight conditions.
Innovation Solution
A system utilizing ultra-wide-band (UWB) time-slotted ranging with synchronized anchors and tags that perform time-of-flight measurements during designated time windows, allowing for precise distance calculations using time-of-flight measurements and battery-efficient tag operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If RADAR is used to measure distance, then long-distance tracking is achieved, but precision deteriorates to feet/miles level
Solution Approach 1:
The patent changes the fundamental measurement parameter from radio signal reflection (RADAR) to time-of-flight measurement of UWB pulses. By using extremely precise timing (picosecond-level counters) to measure the time for a radio pulse to travel to and from the target, the system achieves centimeter-level precision while maintaining effective indoor tracking distances.
Solution Approach 2:
The patent replaces the mechanical/electronic RADAR system with a time-synchronization system using UWB radio pulses and precise digital counters. Instead of measuring signal strength or frequency shift, the system substitutes a direct time measurement approach using synchronized clocks in anchors and tags, achieving superior precision.
2Adaptability or versatility
If GPS is used for location tracking, then outdoor positioning is achieved, but indoor tracking capability deteriorates due to line-of-sight requirements
Solution Approach 1:
The patent introduces UWB radio pulses as an intermediary mechanism that does not require line-of-sight to satellites. By using local anchors and tags with time-synchronized clocks, the system creates an indoor positioning infrastructure that mediates between the need for precise location data and the absence of satellite signals, enabling reliable tracking indoors.
Solution Approach 2:
Instead of relying on external satellite signals coming down to Earth, the patent inverts the approach by creating a local positioning system where anchors and tags communicate directly with each other using UWB pulses. The timing reference is distributed locally rather than received from space, enabling indoor operation.
3Length of stationary object
If high-powered radio signals are used for tracking, then long-range detection is achieved, but energy consumption increases
Solution Approach 1:
The patent implements periodic UWB pulse transmission instead of continuous high-powered signals. Anchors and tags exchange short, periodic ranging pulses at controlled intervals, allowing the system to maintain tracking capability while dramatically reducing average power consumption compared to continuous transmission.
Solution Approach 2:
The patent uses partial action by transmitting only the minimum necessary UWB pulses for ranging measurements rather than continuous signals. The system sends sporadic measurement pulses only when position updates are needed, reducing energy consumption while maintaining sufficient tracking functionality.
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 accurate location tracking of objects within facilities with centimeter-level precision by determining distances between anchors and tags, optimizing energy use, and adapting to varying tag densities and battery life requirements.
Implementation Method 1
determine time-of-flight measurements for the responsive UWB transmissions... determining distances to the tag based on the time-of-flight measurements
Data Source
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AI summary
Methods, systems, and computer readable media for time-slotted ultra-wide-band (UWB) object tracking are disclosed. A system includes anchors and tags having synchronized timing systems. The anchors are configured for performing time-slotted UWB ranging during time windows, one for each tag. During each window, the anchors sequentially transmit UWB transmissions in designated time slots, one for each anchor, as specified by an order of operation. The anchors receive responsive UWB transmissions from the tag assigned to the time window and determine time-of-flight measurements for the responsive UWB transmissions.