UWB Robotic Localization Using TDOA and Reference Grid
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Solution Overview
Problem
Current methods for determining the position and pose of robotic systems indoors are inaccurate due to limitations in GPS signals and existing UWB techniques, which require precise anchor positions and are restricted to two-dimensional location sensing, failing to account for complex three-dimensional orientations and real-time navigation needs.
Innovation Solution
A robotic localization and orientation system using near-simultaneous RF measurements integrates Time Difference of Arrival (TDOA) estimates from multiple RF transmitter-receiver pairs to establish the location and pose of robots or end effectors, allowing for accurate navigation and orientation within environments without prior knowledge of anchor node locations, using a digital map and UWB signals to guide robotic movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If GPS or RF signal strength indication techniques are used for position determination, then the system can operate indoors or in select outdoor situations, but the position accuracy deteriorates to only a few meters which is too inaccurate for specific robotic applications
Solution Approach 1:
The patent replaces traditional RF signal strength indication methods with ultra-wideband (UWB) signaling technology. UWB uses time-of-flight measurements with timing accuracy to a fraction of a nanosecond, providing range accuracy within a few centimeters instead of meters. This substitution of the measurement mechanism resolves the contradiction by maintaining indoor operation capability while dramatically improving position accuracy for robotic applications.
Solution Approach 2:
The patent changes the measurement parameter from RF signal strength indication to UWB time-of-flight measurement. By using the speed of light and precise timing measurements, the system achieves centimeter-level accuracy instead of meter-level accuracy. This parameter change enables both indoor operation and high precision positioning simultaneously.
2Measurement precision
If prior UWB techniques are used for position determination, then range accuracy improves to within a few centimeters, but the system requires that the precise position of reference objects or anchors be fully known beforehand
Solution Approach 1:
The patent applies preliminary action by having the mobile robot autonomously determine anchor positions before performing the main positioning task. The robot moves through the environment, uses its known tag positions and UWB measurements to calculate anchor locations, stores this information, then uses it for accurate positioning. This eliminates the need for manual anchor position configuration while maintaining centimeter-level accuracy.
Solution Approach 2:
The system implements self-service by enabling the mobile robot to automatically determine its own environment's anchor positions without external intervention. The robot uses its onboard sensors, known tag positions, and UWB measurements to autonomously map and locate anchors, then uses this self-determined information for precise positioning throughout the environment.
3Measurement precision
If prior UWB techniques are used for location determination, then the system can determine the location of a single point in space, but it fails to provide a full description of robot location and pose including three-dimensional orientations
Solution Approach 1:
The patent segments the pose determination problem into multiple components by using multiple tags at known positions on the robot. Each tag provides location information, and by combining measurements from multiple tags, the system determines both the robot's position and its three-dimensional orientation (pose). This segmentation approach enables full pose determination rather than just single-point location.
Solution Approach 2:
The patent transitions from two-dimensional location sensing to full three-dimensional pose determination. By placing tags at multiple known positions on the robot and using UWB measurements from multiple anchors, the system calculates the robot's position and all three rotational orientations (roll, pitch, yaw). This dimensional expansion provides complete pose information needed for complex robotic navigation and manipulation tasks.
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 system enables precise and accurate determination of a robot's or end effector's location and pose in real-time, allowing for effective navigation and orientation in complex environments, overcoming the limitations of existing technologies by providing a robust and adaptable solution for indoor robotic systems.
Implementation Method 1
integrate in near-real time individual Time Difference of Arrival (TDOA) estimates from multiple RF transmitter-receiver pairs
Data Source
AI summary
A method and system for determining position and/or pose of an object. A robotic device moves throughout an environment and includes a master transceiver tag and, optionally, additional tags. The environment includes a plurality of anchor nodes that are configured to form a network. A master anchor node is in communication with at least a portion of the plurality of anchor nodes and is configured to transmit a ranging message as a UWB signal, receive a ranging message response from each other anchor node in the network, generate a reference grid representing physical locations of the plurality of anchor nodes within the network based upon the received ranging message responses, and distribute the reference grid to each of the other anchor nodes. The master transceiver tag receives the reference grid information and, based upon further calculations, determines a specific position and pose of the robotic device within the environment.