Radio Position Estimation via Circle-Halfline Intersection
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Solution Overview
Problem
Existing position estimation methods for radio devices, such as trilateration and the spring model, face challenges in accurately estimating distances between radio devices and access points, leading to significant discrepancies between estimated and actual positions.
Innovation Solution
A position estimation apparatus that includes a distance estimating section to calculate estimated distances based on signal reception strength, a first position estimating section for trilateration, a second section to estimate a circle centered at the access point with maximum reception strength, and a final section to determine the intersection of the circle and a half-line, enhancing accuracy by considering propagation factors and transmission power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If trilateration or spring model is used for position estimation, then position estimation can be provided, but the accuracy of distance estimation between radio device and access points deteriorates
Solution Approach 1:
The patent introduces an intermediary geometric construction (circle and half-line intersection) between the raw distance estimates and the final position. The second position estimating section creates a circle centered at the access point with maximum reception strength, and the final position estimating section finds the intersection of this circle with a half-line from the first position estimate. This intermediary geometric approach refines the position estimate by incorporating both distance information and angular direction information, thereby improving measurement precision without sacrificing reliability
Solution Approach 2:
The patent changes the parameter representation from direct distance estimates to a combination of circular arc constraints and angular half-line constraints. By transforming the position estimation problem into finding the intersection of a circle (representing constant distance from reference access point) and a half-line (representing directional information from first estimate), the system achieves more accurate position determination by utilizing the geometric properties of the parameter space
2Ease of operation
If low-accuracy distance estimates are used for trilateration, then position estimation can be performed, but the estimated position differs significantly from the actual position
Solution Approach 1:
The patent implements a feedback mechanism where the first position estimate serves as input to generate the half-line, which then feeds into the final position estimation alongside the circle constraint. The system uses the initial position estimate to define the angular direction (half-line), and this feedback loop allows the final position to be refined based on both the distance constraint (circle) and the directional information (half-line from first estimate), significantly improving position accuracy while maintaining operational feasibility
Solution Approach 2:
The patent transitions from a one-dimensional distance-based estimation to a two-dimensional geometric constraint system. By introducing the angular dimension through the half-line (derived from the first position estimate) and combining it with the radial distance constraint (circle from second position estimate), the system resolves the position in two dimensions simultaneously, thereby achieving higher accuracy while preserving ease of operation
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 improves the accuracy of radio device position estimation by combining multiple distance estimates and using propagation factors, resulting in a more precise determination of the radio device's position.
Implementation Method 1
a distance estimating section that estimates actual distances between wireless access points that receive the signal and the radio communication device as estimated distances based on the reception strength of the signal
Data Source
AI summary
A position estimation apparatus estimates the position of a radio communication device that outputs a signal, where the apparatus includes a distance estimating section, a first position estimating section, a second position estimating section, and a final position estimating section, where the distance estimating section estimates actual distances between wireless access points receiving the signal and the radio communication device as estimated distances based on the reception strength of the signal, where the first position estimating section estimates the position of the radio communication device, where the second position estimating section estimates a circle centered at one of the wireless access points with the maximum reception strength, and where the position estimated by the final position estimating section is estimated as the position of the radio communication device.