Visual Positioning Using Horizontal Angles
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Solution Overview
Problem
Existing position determination techniques in wireless communication systems, such as GPS, are inaccurate in urban environments due to restricted satellite views and multipath effects, and computationally expensive computer vision methods are costly and inefficient.
Innovation Solution
An access terminal equipped with multiple cameras configured to capture images and calculate a refined position using horizontal angles between identified keypoints, which are determined as the intersection of position circles defined by known geographical locations, providing a more accurate and cost-effective solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GPS techniques are used for position determination, then the system can provide location services, but the accuracy deteriorates in urban environments due to restricted satellite views and multipath effects
Solution Approach 1:
The patent replaces GPS satellite-based positioning with a terrestrial camera-based visual positioning system. Instead of relying on satellite signals that are blocked or reflected in urban environments, the system uses cameras to capture images of terrestrial features and calculates position through geometric relationships between identified keypoints and reference keypoints, eliminating vulnerability to satellite signal interference.
Solution Approach 2:
The patent introduces camera-captured images and identified keypoints as intermediaries between the access terminal and the final position determination. The system captures images, identifies keypoints in those images, matches them with reference keypoints, and uses the geometric relationships of these intermediary elements to calculate precise position, thereby avoiding direct reliance on GPS signals.
2Measurement precision
If computer vision methods with iterative numerical methods are used to determine position, then the accuracy improves, but the computational cost becomes prohibitive for access terminals
Solution Approach 1:
The patent extracts the essential geometric information needed for positioning from complex computer vision processing. Instead of performing full iterative optimization to minimize reprojection error, the system identifies keypoints, matches them with reference points, and directly calculates position using geometric relationships and horizontal angles, extracting only the necessary computational elements while discarding the computationally expensive iterative optimization process.
Solution Approach 2:
The patent replaces expensive computationally intensive iterative numerical methods with inexpensive closed-form geometric calculations. The system uses straightforward trigonometric relationships and circle intersection mathematics that can be performed efficiently on mobile devices, substituting costly computational processes with affordable alternative calculations that achieve sufficient accuracy without requiring high-performance computing resources.
3Area of stationary object
If a single camera is used for position determination, then the device complexity is low, but the angle of view is insufficient to capture enough reference keypoints in urban environments
Solution Approach 1:
The patent merges the capabilities of multiple cameras into a unified positioning system. By combining images from multiple cameras, the system creates a composite view that encompasses a wider effective angle of view, allowing the capture of more reference keypoints that would be invisible to any single camera, thereby improving positioning accuracy without requiring any individual camera to have an excessively wide angle of view.
Data Source
AI summary
An access terminal of a wireless communication system includes a transceiver configured to receive wirelessly multiple reference keypoints and a geographical location of each respective reference keypoint, each geographical location being a location near an estimated position of the access terminal; at least one camera communicatively coupled to the transceiver and configured to capture an image; and a processor communicatively coupled to the at least one camera and configured to calculate a refined position of the access terminal, that is more accurate than the estimated position, using first and second horizontal angles between the geographical locations of respective first and second pairs of reference keypoints determined as each corresponding to a respective image keypoint identified within the image captured by the at least one camera.