Positioning Device Multipath Elevation Filtering
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Solution Overview
Problem
In urban areas with tall buildings, GPS receivers often face challenges in receiving direct signals from satellites due to multipath interference, leading to positioning errors and potential impossibility of positioning when multipath is excluded.
Innovation Solution
A positioning device that stores and utilizes multipath recurrent district elevation information to generate elevation information, allowing for precise positioning even in areas with frequent multipath interference, while minimizing storage capacity and simplifying construction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multipath signals are excluded from positioning calculation, then positioning precision is improved, but positioning becomes impossible in urban areas with tall buildings
Solution Approach 1:
The patent applies local quality by treating multipath signals differently based on their origin characteristics. Instead of uniformly excluding all multipath signals, the system identifies signals from satellites that are geometrically positioned above the horizon and treats them as reliable, while excluding signals that exhibit multipath characteristics. This localized approach to signal validation allows the system to maintain high precision by excluding harmful multipath while retaining availability by accepting valid direct signals.
Solution Approach 2:
The patent changes the parameter of signal evaluation from simple signal strength or correlation metrics to a geometric parameter-based approach. By calculating the elevation angle of satellites and using this geometric parameter to distinguish direct signals from multipath signals, the system transforms the positioning problem into one that can reliably differentiate signal types, thereby maintaining both precision and availability.
2Adaptability or versatility
If all satellite signals are used for positioning, then positioning availability is improved, but positioning precision deteriorates due to multipath errors
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing the elevation angles of satellites in advance. Before performing positioning calculations, the system has already prepared the geometric parameters needed to evaluate incoming signals. This preliminary preparation allows the system to quickly and accurately distinguish between direct and multipath signals during real-time positioning, maintaining precision without sacrificing availability.
Solution Approach 2:
The patent introduces an intermediary element - the satellite elevation angle calculation - that mediates between the raw satellite signals and the positioning calculation. This intermediary parameter serves as a filter that helps identify which signals should be included in positioning calculations, thereby resolving the conflict between using all signals for availability and filtering signals for precision.
3Measurement precision
If detailed elevation information is stored for all areas, then positioning precision in multipath districts is improved, but storage capacity load increases
Solution Approach 1:
The patent applies segmentation by dividing the geographic space into discrete grid cells and storing elevation information only for specific locations within these cells. Rather than maintaining continuous or comprehensive elevation data, the system segments the information storage to only those areas and resolutions necessary for multipath identification, significantly reducing storage requirements while maintaining positioning precision where needed.
Solution Approach 2:
The patent implements partial action by storing elevation information selectively rather than comprehensively. The system stores elevation data only for divisional areas where multipath conditions are likely to occur and only at the resolution necessary for practical positioning purposes. This partial storage approach provides sufficient precision for the intended application without the excessive storage burden of complete global elevation data.
Data Source
AI summary
A positioning device for receiving a satellite signal corresponding to a signal from a positioning satellite including a multipath recurrent district elevation information storing unit for storing multipath recurrent district elevation information indicating the elevation of a multipath recurrent district as elevation information of plural divisional areas, an elevation information obtaining position information generating unit for receiving the satellite signals and generating elevation information obtaining position information to obtain the elevation information, an elevation information obtaining unit for obtaining the elevation information of the divisional area corresponding to the elevation information obtaining position information and an elevation information using present position information generating unit for generating elevation information using present position information indicating the present position on the basis of the satellite signals and the elevation information.