Navigation Apparatus Positioning Using Map Matching Feedback
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Solution Overview
Problem
Navigation apparatuses face challenges in providing accurate positioning data due to poor GPS signal reception and accumulative errors in map matching algorithms, leading to incorrect route calculations, especially in areas with fewer visible satellites or weak signal regions.
Innovation Solution
The method involves storing previous positioning and map-matching parameters, which are used in conjunction with current GPS signals to compute more accurate current positioning parameters, reducing accumulative errors by incorporating previous map-matching results into subsequent calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GPS signal reception is used for positioning, then positioning function is provided, but positioning accuracy deteriorates in areas with poor signal reception or fewer visible satellites
Solution Approach 1:
The patent combines GPS positioning with map-matching technology to create a hybrid positioning system. When GPS signal is available, it provides positioning data; when GPS signal is poor or unavailable, the system switches to map-matching based on mobile device movement data and map data to maintain positioning function and accuracy.
Solution Approach 2:
The patent introduces map-matching as an intermediary positioning method. Instead of relying solely on GPS, the system uses map-matching algorithms that compare mobile device trajectory with map road networks to determine position, serving as a mediator when GPS fails or provides inaccurate data.
2Measurement precision
If map matching algorithm is used to calibrate positioning data, then positioning accuracy is improved, but accumulative errors occur over time leading to incorrect route calculations
Solution Approach 1:
The patent performs preliminary calibration by matching mobile device trajectory with map road networks before final route calculation. This preliminary action corrects GPS errors proactively, and the system periodically re-calibrates to prevent accumulative errors from affecting route accuracy.
Solution Approach 2:
The system implements feedback mechanisms where positioning results are continuously evaluated against map data. When deviations are detected, the system adjusts the positioning calculations by re-matching with map roads, creating a closed-loop feedback system that corrects accumulative errors.
3Productivity
If previous positioning parameters are used for computation, then computation speed is improved, but positioning accuracy deteriorates due to error accumulation
Solution Approach 1:
The system uses feedback to determine whether to use previous positioning parameters. When GPS signal quality is good, it uses previous parameters for fast computation. When signal quality deteriorates or map-matching is performed, the system resets or corrects the previous parameters to prevent error accumulation, thus maintaining both speed and accuracy.
Data Source
AI summary
A positioning method for a navigation apparatus and the navigation apparatus are provided. The positioning method includes steps of receiving a Global Positioning System (GPS) signal; reading a previous position-velocity-time (PVT) data; reading a previous map matching (MMT) result; and computing current PVT data according to at least one of the previous PVT data and the previous MMT result.