Inertial Navigation Error Correction via Map Matching
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Solution Overview
Problem
Conventional inertial navigation systems face accuracy issues due to errors introduced by gyroscopes and odometers, which affect the calculation of a moving object's position and orientation.
Innovation Solution
A positioning system that searches for orientation-matched and position-matched road sections on an electronic map to correct the calculated position and orientation of a moving object using a database of road sections, utilizing GPS signals and dead reckoning data when GPS is unavailable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional inertial navigation systems use gyroscopes and odometers for position calculation, then the system can operate independently of external signals, but the accuracy of calculated position and orientation deteriorates due to sensor errors
Solution Approach 1:
The patent introduces electronic maps as an intermediary reference system. The map data serves as a mediator between the inertial navigation system's calculated position and the actual position, allowing error correction without requiring continuous external signal input. The system compares calculated position with map-based expected position to correct drift errors.
Solution Approach 2:
The system implements feedback by continuously comparing the calculated position from inertial sensors with the expected position derived from electronic map data. This feedback loop enables real-time error correction, where discrepancies between calculated and expected positions are used to adjust and refine the navigation solution, thereby maintaining accuracy over time.
2Measurement precision
If the system uses electronic maps for position correction, then the measurement precision improves, but the device complexity increases due to database search and matching operations
Solution Approach 1:
The patent segments the electronic map data into road section elements with specific properties (orientation, position, shape). This segmentation allows the system to process map data in manageable units rather than handling the entire complex map structure at once. The road section elements can be independently queried and matched, reducing the computational complexity of map processing.
Solution Approach 2:
The system performs partial actions by searching for only the necessary road section elements required for position correction, rather than processing the entire electronic map database. The search queries are targeted and selective, retrieving only the minimal set of map data needed for the current navigation context, thereby reducing processing complexity while maintaining accuracy.
3Measurement precision
If the system performs comprehensive map data search and matching, then the position accuracy improves, but the processing time increases
Solution Approach 1:
The patent applies preliminary action by pre-processing and organizing electronic map data into structured road section elements with pre-computed properties. This preparation allows the system to perform rapid queries and matching operations during actual navigation, avoiding the need for time-consuming comprehensive searches in real-time. The map data is pre-organized in a way that enables efficient retrieval of relevant road sections.
Solution Approach 2:
The system uses partial action by performing targeted searches for specific road section elements based on current position and orientation estimates, rather than conducting comprehensive full-map searches. This selective approach retrieves only the necessary map data for the current navigation context, significantly reducing processing time while maintaining sufficient accuracy for position correction.
Data Source
AI summary
A database for a set of orientation-matched road (OMR) sections is searched according to a calculated orientation of an object and orientations of road sections stored in the database. The OMR sections are searched for a position-matched road (PMR) set according to a calculated position of the object and positions of the OMR sections. The PMR set includes one or more PMR sections. The object is located using the PMR set.