GNSS Dead Reckoning Positioning System with GIS Map Matching
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Solution Overview
Problem
Global Navigation Satellite Systems (GNSS) face challenges in maintaining accurate positioning due to environmental factors like weather and tunnel environments, where satellite signals are blocked, leading to errors in location estimation by dead reckoning devices, which are only temporary and less precise.
Innovation Solution
A positioning system combining a GNSS module, a dead reckoning module, and a Geographic Information System (GIS) module, where the GIS module improves the precision of positioning data by integrating and fitting it to a map, and using a calculating module to recursively feedback data for improved estimation, even when GNSS signals are unavailable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dead reckoning is used to estimate location when GNSS fails, then positioning capability is maintained, but positioning precision deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the GIS module provides map-matched position information back to the dead reckoning module. This feedback corrects the cumulative errors in dead reckoning estimation by periodically anchoring the position estimate to accurate map-based locations, thereby maintaining both reliability and precision during GNSS outages.
Solution Approach 2:
The GIS module acts as an intermediary between the dead reckoning module and the final position output. It receives raw dead reckoning estimates, refines them through map matching algorithms, and provides corrected position information, thereby improving precision without compromising the continuous positioning capability provided by dead reckoning.
2Duration of action of moving object
If dead reckoning is used when GNSS signals are blocked, then positioning can continue, but estimation errors increase over time
Solution Approach 1:
The system uses feedback from the GIS module to periodically correct dead reckoning estimates. By matching the estimated trajectory against known map features and road networks, the system resets cumulative errors, allowing positioning to continue accurately for longer durations during GNSS outages.
Solution Approach 2:
The system performs preliminary map matching and error correction at regular intervals before significant drift occurs. This proactive approach prevents large estimation errors from developing, maintaining accuracy over extended periods when GNSS is unavailable.
3Measurement precision
If GIS module is added to improve positioning precision, then system complexity increases
Solution Approach 1:
The GIS module serves multiple functions: it provides map matching for precision improvement, stores geographic reference data for error correction, and enables route guidance capabilities. This multi-functionality justifies the added complexity by delivering multiple benefits from a single modular component.
Solution Approach 2:
The GIS module is designed as a modular intermediary that interfaces cleanly with existing GNSS and dead reckoning modules. This standardized integration approach minimizes the increase in system complexity while achieving the goal of improved positioning precision through map-based refinement.
Data Source
AI summary
The invention provides a positioning system. In one embodiment, the positioning system comprises a Global Navigation Satellite System (GNSS) module, a dead reckoning module, a Geographic Information System (GIS) module, and an calculating module. The GNSS module generates a first positioning data according to satellite communication. The dead reckoning module estimates a second positioning data according to a sensor's measurement data, the first positioning data, and a feedback positioning data of a previous epoch. The GIS module fits the first positioning data to a map to generate a third positioning data taken as a final output of the positioning system. The calculating module integrates the third positioning data and the second positioning data according to predetermined weights to obtain the feedback positioning data of a current epoch, which is recursively fed back to the dead reckoning module for a next estimation.