Calibrating Positioning System Anchor Nodes Using Odometry and Ranging
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Solution Overview
Problem
Current methods for calibrating positioning systems with anchor nodes are either inaccurate due to unrealistic assumptions or require infeasible measurement collections, especially when anchor nodes are difficult to reach.
Innovation Solution
A method using a measurement device with odometry sensors and a localization tag to perform ranging and odometry measurements, compensating for measurement drifts, and employing multiple location estimation algorithms to accurately determine anchor node positions, which are then validated and refined through iterative processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual measurement with laser distance measuring devices is used to configure anchor node positions, then positioning accuracy can be achieved, but the calibration process becomes cumbersome and infeasible when anchor nodes are installed at difficult-to-reach locations
Solution Approach 1:
The patent introduces a measurement device as an intermediary that carries both a localization tag and odometry sensors. This device mediates between the inaccessible anchor nodes and the calibration process by being movable throughout the localization area, collecting ranging measurements from anchor nodes at multiple positions without requiring direct access to the anchor nodes themselves for manual measurement.
Solution Approach 2:
The patent replaces the manual mechanical measurement system (laser distance measuring devices requiring direct access) with an automated system combining radio technology for ranging measurements and odometry sensors for position tracking. This substitution eliminates the need for physical access to anchor nodes while maintaining measurement capabilities through computational methods.
2Ease of operation
If optimization algorithms are used to estimate anchor positions from collected ranging measurements, then calibration can be simplified, but accuracy deteriorates when measurements contain non-Gaussian errors or non-line-of-sight conditions
Solution Approach 1:
The patent changes the error model parameters from assuming Gaussian errors to accounting for non-Gaussian error distributions and non-line-of-sight conditions. The location estimation algorithm is specifically designed to be robust against these realistic error types, adjusting the mathematical parameters and assumptions to match actual measurement conditions in complex environments.
Solution Approach 2:
The patent implements validation using a separate set of ranging measurements to provide feedback on the accuracy of estimated anchor node locations. This feedback mechanism allows the system to identify and correct estimation errors, improving accuracy by comparing predicted positions against independent measurement data and adjusting estimates accordingly.
3Device complexity
If a single location estimation algorithm is used to determine anchor node locations, then the calibration process is simplified, but accuracy is limited by the algorithm's assumptions and error models
Solution Approach 1:
The patent merges multiple location estimation algorithms with different characteristics to determine anchor node locations. By combining the results of multiple algorithms that make different assumptions and handle different error types, the system achieves more accurate and robust position estimates than any single algorithm could provide alone.
Solution Approach 2:
The patent creates a multi-functional calibration system that can handle various measurement conditions and error types through multiple estimation algorithms. This universal approach allows the calibration process to adapt to different scenarios (line-of-sight, non-line-of-sight, varying error distributions) without requiring separate specialized procedures for each case.
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 provides a more accurate and feasible calibration of anchor nodes, reducing errors and improving the precision of positioning systems, even in challenging environments.
Implementation Method 1
two-way timing measurements of the time the signals travel between a tag device and an anchor node to thereby measure the distance therebetween
Implementation Method 2
performing, at the plurality of first measurement points using the at least one odometry sensor, first odometry measurements to estimate respective first positions of the measurement device
Data Source
AI summary
Calibrating a positioning system comprising a plurality of anchor nodes used to determine tag positions within a localization area using radio technology. The method includes performing, at a plurality of first measurement points in the localization area using the localization tag, first ranging measurements with respect to the plurality of anchor nodes using the radio technology to determine respective first distances from the measurement device to the plurality of anchor nodes and performing, at the plurality of first measurement points using the at least one odometry sensor, first odometry measurements to estimate respective first positions of the measurement device in the localization area, estimating locations of the plurality of anchor nodes based on the respective first distances determined by the first ranging measurements and the respective first positions estimated by the first odometry measurements, and calibrating the positioning system using the estimated locations of the plurality of anchor nodes.