UGV Navigation Using Relative Map and INS Drift Correction
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Solution Overview
Problem
Unmanned ground vehicles (UGVs) face challenges in autonomous navigation due to inaccuracies in GPS tracking and significant errors from Inertial Navigation System (INS) integration drift, which can lead to collisions with obstacles or entry into non-traversable areas.
Innovation Solution
The implementation of a navigation method using a scanning device to generate a relative map of the environment, divided into cells classified as traversable or non-traversable, with cell sizes larger than the maximal INS drift over a predefined distance, combined with INS data for updating the UGV's location, allowing the vehicle to avoid obstacles and maintain accurate navigation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS tracking is used for navigation, then the system is simple and provides global position information, but the tracking accuracy is insufficient and suffers from discontinuities leading to collisions
Solution Approach 1:
The patent combines GPS tracking with Inertial Navigation System (INS) to create a hybrid navigation system. The INS provides continuous high-frequency position updates to fill GPS discontinuities, while GPS provides absolute position reference to correct INS drift, achieving both continuity and accuracy requirements for safe navigation
Solution Approach 2:
The patent introduces a map-matching intermediary that correlates INS-derived position with known map features. This intermediary corrects INS drift by anchoring the vehicle's estimated position to verified map locations, providing a reliable reference that prevents navigation errors from accumulating
2Speed
If Inertial Navigation System (INS) is used for tracking, then continuous position data is provided, but significant errors accumulate due to integration drift over time
Solution Approach 1:
The patent implements feedback by continuously comparing INS-derived position with actual map features through scanning devices. When discrepancies are detected, the system corrects the INS position estimate, preventing drift accumulation while maintaining continuous high-rate position updates
Solution Approach 2:
The patent performs preliminary action by pre-processing scanning data to create an accurate map of the environment before navigation begins. This pre-established map serves as a reference framework that constrains and corrects INS drift throughout the navigation process
3Measurement precision
If small map cells are used for precise obstacle detection, then obstacle localization accuracy improves, but the number of cells increases leading to higher computational complexity
Solution Approach 1:
The patent segments the map into hierarchical levels: coarse grid cells for general navigation and collision avoidance, with finer segmentation only in regions containing obstacles. This multi-resolution approach maintains obstacle localization accuracy while reducing the total number of cells that require computational processing
Data Source
AI summary
The presently disclosed subject matter includes a system and a method of navigating an unmanned ground vehicle (UGV) vehicle comprising a scanning device and an Inertial Navigation System (INS) being operatively connected to at least one processor. Operating the scanning device for scanning an area surrounding the UGV, and generate scanning output data; Generating, based on the scanning output data, a map representing at least a part of the area, the map being relative to a location of the UGV and comprising cells, each cell is classified to a class selected from at least two classes, comprising traversable and non-traversable, and characterized by dimensions larger than an accumulated drift value of the INS over a predefined distance; receiving INS data indicative of a current location of the UGV and updating a location of the UGV relative to cells in the map based on the INS data.