Visual Localization Mapping for GPS-Denied Ground Vehicles
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Solution Overview
Problem
Autonomous ground vehicles face challenges in determining their position accurately, especially in environments with obstructions, where GPS signals may be delayed or unreliable.
Innovation Solution
The implementation of a visual localization system that generates visual maps using images captured by onboard cameras. These images are processed to determine visual features, which are compared to features stored in the visual map to predict the vehicle's position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GPS signals are used to determine vehicle position, then position information can be obtained, but the position may be inaccurate or unavailable in environments with obstructions
Solution Approach 1:
The patent introduces visual features and image processing as an intermediary mechanism between the vehicle and its environment. By capturing images with onboard cameras and comparing visual features against a pre-stored visual map, the system mediates position determination independently of GPS signals, resolving the contradiction between reliability and precision in obstructed environments.
Solution Approach 2:
The patent replaces the GPS satellite-based electromagnetic signal system with an optical image-based visual recognition system. This substitution eliminates dependence on external satellite signals that are vulnerable to obstruction, using instead local visual feature matching that operates autonomously within the vehicle's sensor and processing systems.
2Ease of operation
If GPS initialization period is required, then GPS equipment can start operating, but position information is unreliable during this period
Solution Approach 1:
The patent performs preliminary action by pre-capturing images and pre-determining visual features of the environment during map creation phases. This pre-processing of visual data allows the vehicle to immediately perform position determination upon entering a known area, eliminating the need for GPS-like initialization periods and providing reliable position information from the moment the system operates.
3Adaptability or versatility
If visual maps are generated using onboard cameras, then position can be determined without GPS, but the system complexity increases
Solution Approach 1:
The patent applies multi-functionality by using the same onboard camera system for multiple purposes: capturing images for visual map generation, extracting visual features for position determination, and potentially other vehicle operations. This universal use of the camera system justifies the added complexity by providing versatile position determination capability across different operating conditions.
Data Source
AI summary
Autonomous ground vehicles that are outfitted with onboard cameras and configured to travel within an area or region are programmed with a previously generated visual map of the area or region. The visual map includes a plurality of map points from which images were previously captured and processed to determine visual features of such images. In the event of a loss of one or more position signals, such as GPS signals, the autonomous ground vehicles capture images using one or more of the cameras, and process the images to determine visual features from such images. The visual features determined from such images are compared to the visual map. Positions of one or more of the map points are identified as most likely corresponding to a position of the autonomous ground vehicle where visual features associated with such map points are similar to the visual features determined from such images.