Mobile Geolocation Resetting With Three-Landmark 3D Attitude Estimation
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Solution Overview
Problem
Existing geolocation methods fail to accurately determine both 3D position and 3D attitude of a mobile device using only landmark measurements without a navigation system.
Innovation Solution
A method for geolocating a mobile device by recalibrating it to at least three landmarks, involving bearing, elevation, and distance measurements, utilizing a Gauss-Newton type algorithm for attitude determination, and iterative position estimation with consistency checks and variance calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If 3D position and 3D attitude geolocation is attempted using only three landmarks without a navigation system, then the device complexity is reduced, but the measurement precision and reliability deteriorate because existing methods cannot accurately determine both position and attitude from limited landmark measurements
Solution Approach 1:
The patent transforms the measurement problem by introducing elevation angles as an additional dimensional parameter. By measuring bearing, elevation, and distance to three landmarks, the system creates a three-dimensional measurement space that provides sufficient constraints to solve for both 3D position (x, y, z) and 3D attitude (roll, pitch, heading) without requiring a navigation system. This dimensional enrichment allows the mathematical system to become determinate.
Solution Approach 2:
The patent replaces the mechanical navigation system (gyroscopes, accelerometers, magnetometers) with a pure geometric-optical measurement approach. Instead of using inertial sensors to track attitude changes, the system uses optical bearing and elevation measurements combined with distance measurements to computationally derive attitude information through triangulation and trilateration mathematics, substituting mechanical sensing with geometric computation.
2Loss of information
If bearing, elevation, and distance measurements are taken to three landmarks, then the information available for geolocation increases, but the computational complexity and algorithm complexity increase significantly
Solution Approach 1:
The patent segments the geolocation problem into distinct computational stages: first solving for position using distance and bearing measurements, then separately solving for attitude using elevation measurements and the derived position. This segmentation breaks the complex coupled problem into manageable sub-problems that can be solved sequentially using standard mathematical techniques, reducing the overall algorithmic complexity.
Solution Approach 2:
The patent introduces the mobile device's position as an intermediary variable that bridges the measurement data and the final attitude determination. By first calculating position from the bearing and distance measurements, and then using this position information as a foundation for attitude calculation, the system creates a computational intermediary that simplifies the overall solution process and makes the mathematics more tractable.
Data Source
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AI summary
The geolocation process includes the following steps: - acquisition of bearing, elevation and distance measurements of the three landmarks in a reference frame of the mobile device, - determination of an estimated attitude of the mobile device in a terrestrial reference frame by optimizing a criterion having as its only unknown the estimated attitude of the mobile device and using the bearing, elevation and distance measurements, and the known positions of the three landmarks in the terrestrial reference frame, - conversion of the bearing and elevation measurements of the three landmarks to obtain azimuths and elevations of the three landmarks in the terrestrial reference frame using the estimated attitude, - iterative determination of an estimated position of the mobile device in the terrestrial reference frame using the azimuths, elevations and distances of the three landmarks.