Angle of Direct Path Determination via Mobility Data
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing indoor localization techniques, such as AoA and RSSI-based methods, face challenges in distinguishing the direct path from multipath reflections, leading to estimation errors, especially when the direct path is weak or blocked, resulting in inaccurate angle of direct path determination.
Innovation Solution
The proposed solution leverages mobility information from sensors like accelerometers, gyroscopes, and compasses to compute changes in angle-of-arrival and distance, allowing for the identification of the direct path angle by comparing these changes, thereby distinguishing it from reflected paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If AoA or RSSI based estimation techniques are used to determine location, then location estimation can be performed, but estimation errors occur when direct path is weak or blocked due to inability to distinguish from multipath reflections
Solution Approach 1:
The patent introduces an intermediary variable - the angle of direct path (ANDP) - which serves as a mediator between the received signal and the final location estimation. By computing ANDP separately using geometric relationships between transmitter, receiver, and reflected path endpoints, the system can distinguish the direct path angle from multipath reflection angles, thereby improving both measurement precision and reliability in determining location.
2Measurement precision
If existing techniques are used to estimate ANDP, then location can be determined, but large estimation errors occur when reflected paths are stronger than direct path
Solution Approach 1:
The patent segments the signal analysis process into distinct components: identifying the direct path signal component separately from reflected path components. By computing the ANDP independently using geometric relationships (distances between transmitter, receiver, and reflected path endpoints) rather than relying on signal strength comparisons, the system can accurately determine the direct path angle even when reflected paths are stronger, thereby eliminating multipath interference errors.
3Reliability
If direct path is blocked, then signal transmission is affected, but existing techniques falsely declare reflected path angle as ANDP leading to large errors
Solution Approach 1:
The patent implements a feedback mechanism where the computed ANDP is continuously compared with the angle of the strongest received signal. When they diverge significantly (indicating direct path blocking or weakness), the system uses the geometrically-computed ANDP rather than the signal-strength-based AoA estimate. This feedback loop ensures reliable ANDP identification by correcting for cases where multipath reflections dominate the received signal, thereby maintaining both reliability and precision in location determination.
Data Source
AI summary
A signal transmitted from a mobile device is received at a device. A change in angle-of-arrival (AoA) of the signal is computed as the mobile device moves from a first location to a second location. A first distance and a second distance of the mobile from the device corresponding to the first and second locations, respectively are computed. A displacement of the mobile device from the first location to the second location is computed based on mobility information provided by a sensor of the mobile device. A change in an angle of direct path (ANDP) of the signal is computed based on the first distance, the second distance, and the displacement. The ANDP is determined based on a comparison of the change in AoA to the change in ANDP.