UWB Ranging Accuracy in Non-Line-of-Sight Conditions
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Solution Overview
Problem
Ultrawideband (UWB) devices experience reduced ranging accuracy in non-line of sight (NLOS) conditions due to signal obstruction, affecting applications like digital keys and consumer asset tracking, where decimeter-level accuracy is required.
Innovation Solution
A multi-level adaptation algorithm in UWB capable wireless devices detects NLOS conditions and configures transceiver parameters such as transmit power, packet length, and receiver antenna configuration to improve ranging accuracy, using input from Bluetooth or WiFi range measurements and channel state information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If UWB devices use standard transceiver parameters for ranging, then the device complexity is low, but the ranging accuracy degrades in non-line of sight conditions
Solution Approach 1:
The patent implements dynamic transceiver parameter configuration where the system automatically adjusts parameters such as transmit power, packet length, and receiver antenna configuration based on detected NLOS conditions. This dynamic adaptation allows the system to maintain high ranging accuracy across varying environmental conditions without requiring manual intervention or complex hardware redesign.
Solution Approach 2:
The patent changes physical and operational parameters of the transceiver including transmit output power, packet length, and receiver antenna configuration in response to NLOS detection. By modifying these parameters adaptively, the system compensates for signal degradation in obstructed environments while maintaining measurement precision.
2Measurement precision
If UWB devices increase transmit power to improve ranging accuracy in NLOS conditions, then the ranging accuracy improves, but the energy consumption increases
Solution Approach 1:
The system dynamically adjusts transmit power based on real-time NLOS detection rather than operating at constant high power. This dynamic power control allows the system to consume additional energy only when and where needed (in NLOS conditions), while maintaining low power consumption during LOS conditions, thus resolving the contradiction between accuracy and energy usage.
Solution Approach 2:
The patent employs feedback mechanisms where the system continuously monitors signal quality and NLOS conditions, then adjusts transmit power accordingly. This closed-loop control ensures that energy is not wasted on continuous high-power transmission, but rather applied selectively when measurement accuracy requires it, optimizing the trade-off between precision and energy consumption.
3Reliability
If UWB devices use single radio link for ranging, then the device complexity is low, but the reliability of distance measurement decreases in obstructed environments
Solution Approach 1:
The patent makes the wireless device multi-functional by enabling it to operate with multiple radio links (UWB, WiFi, Bluetooth) for ranging operations. Each radio link serves the universal purpose of distance measurement, with the system automatically selecting or switching between links based on environmental conditions. This multi-functionality enhances reliability without requiring separate dedicated systems for different ranging scenarios.
Solution Approach 2:
The patent introduces an intermediary layer of intelligence that manages coordination between multiple radio links. This intermediary functionality detects NLOS conditions, selects appropriate alternative radio links, and coordinates parameter configurations across different technologies. By adding this intermediary control layer, the system achieves higher reliability through multi-link operation while managing the complexity through centralized coordination rather than requiring complex distributed systems.
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 solution enhances UWB ranging accuracy in NLOS conditions by modifying transceiver parameters, thereby improving measurement reliability and consistency with digital key applications.
Implementation Method 1
determining a time-of-flight variance value associated with the plurality of radio frequency signals, and detecting the non-line of sight path based at least in part on the time-of-flight variance value
Implementation Method 2
receiving a plurality of radio frequency signals on the first radio link or the second radio link, and detecting the non-line of sight path based on the plurality of radio frequency signals
Data Source
AI summary
Techniques are provided for improving ranging accuracy of ultrawideband (UWB) devices. An example method for obtaining a distance measurement with a wireless node includes obtaining a first distance measurement using a first radio link, determining a status of a second radio link in response to the first distance measurement being less than a threshold distance, configuring one or more transceiver parameters associated with the second radio link in response to determining the second radio link is utilizing a non-line of sight path, and obtaining a second distance measurement using the second radio link and the one or more transceiver parameters.