Mobile Device Reorientation with Imprecise Reference-Point Positions
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Solution Overview
Problem
Existing geolocation methods are limited to using three landmarks with precise positions and do not provide an estimate of geolocation accuracy, especially when landmarks have imprecise positions and uncertain position measurements.
Innovation Solution
A recalibration method that utilizes any number of landmarks with known position uncertainty, employing an optimal global statistical approach to determine the mobile device's position by analyzing bearing measurements, incorporating both landmark and direction measurement inaccuracies, and includes a verification of observability criteria.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If bearing methods using three landmarks are used, then geolocation can be determined, but the method does not provide an estimate of geolocation accuracy and is limited to precisely known landmark positions
Solution Approach 1:
The invention changes the parameter of landmark position precision from 'precise' to 'imprecise with known uncertainty'. The method accepts landmark positions with uncertainty characterized by standard deviations (σi) and incorporates these uncertainties into the geolocation calculation through a statistical approach that optimizes the use of bearing measurements from multiple landmarks while accounting for both landmark and direction measurement inaccuracies
Solution Approach 2:
The invention introduces feedback by using the known uncertainty parameters of landmarks to adjust and optimize the geolocation calculation. The method iteratively refines the position estimate by considering the reliability (uncertainty) of each landmark, giving more weight to more reliable landmarks and less weight to less reliable ones, thereby providing both position estimation and accuracy assessment
2Measurement precision
If multiple landmarks with imprecise positions are used, then better geolocation accuracy can be achieved, but the computational complexity increases
Solution Approach 1:
The invention applies partial action by using a subset of available landmarks that provides sufficient geolocation accuracy without requiring all possible landmarks. The method can determine position using three or more landmarks with imprecise positions, which is fewer than using multiple precise landmarks, while still achieving optimal accuracy through the statistical approach that accounts for uncertainty
Solution Approach 2:
The method changes the approach from requiring precise landmark positions to accepting imprecise positions with known uncertainty. This parameter change allows the use of more landmarks while managing computational complexity through an optimal global statistical approach that efficiently processes the uncertainty information
Data Source
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AI summary
The present invention relates to a reorienting method based on a plurality of reference points, comprising steps of acquiring (110) M measurements of the azimuthal angle of the reference points, positions of the reference points and precisions associated with these positions; converting (120) a vector of azimuthal-angle measurements into a vector of angular deviations; determining (140), using a linear observation model, an initial approximation of the position of the movable device, which is modelled as a point representative of the points of intersection of a plurality of iso-curves, each iso-curve representing a circular arc comprised between a pair of reference points, the angle subtended by the circular arc at the centre of the circle being equal to twice the angular deviation between this pair of reference points; and determining (150) a following approximation of the position of the movable device and the associated precision on the basis of a preceding approximation, using an iterative relationship.