Road Sign and RSU Localization for GPS-Denied Vehicle Positioning
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Solution Overview
Problem
Autonomous vehicles face challenges in accurately determining their location due to unreliable GPS signals, especially under obstructed conditions, and inaccuracies from Inertial Measurement Unit (IMU) sensors, which can lead to significant errors in path planning and speed control, potentially causing safety hazards.
Innovation Solution
The method involves obtaining a vehicle's location using Roadside Unit (RSU) signals and sensor measurements, comparing it with GPS and IMU-based locations to validate accuracy, and employing a system with processors and memory to determine a valid location by integrating data from various sensors like cameras, LIDAR, and GNSS receivers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GPS signals are used for location determination, then the system can provide global coverage and basic positioning capability, but the location accuracy degrades significantly under obstructed conditions such as tall buildings, mountains or canyons
Solution Approach 1:
The patent combines multiple location determination systems (GPS, IMU, and road sign recognition) into a unified localization system. The system integrates data from GPS receivers, IMU sensors, and camera-based road sign detection to compute a more accurate and reliable vehicle position, especially in GPS-denied environments such as urban canyons or mountainous areas.
Solution Approach 2:
The patent introduces road signs as intermediary reference objects that mediate between the vehicle and the environment for location determination. By detecting known road signs (whose positions are pre-mapped) and measuring relative position to them, the system can accurately determine vehicle location without relying solely on satellite signals.
2Productivity
If Inertial Measurement Unit (IMU) sensors are used to determine distance traveled and heading, then the system can provide continuous positioning data, but inaccuracies in sensor measurements accumulate over time resulting in significant error
Solution Approach 1:
The patent implements a feedback mechanism where the system continuously compares the position estimated by IMU sensors with the position determined by detecting known road signs. When discrepancies are detected, the system uses the road sign-based position to correct and reset the IMU drift, thereby maintaining long-term positioning accuracy while preserving the continuous data rate advantage of IMU sensors.
3Ease of operation
If traditional GPS and IMU systems are used for navigation, then the system can provide basic location information, but the location accuracy is insufficient for safe autonomous driving path planning and speed control
Solution Approach 1:
The patent creates a multi-functional localization system that can operate effectively in both GPS-available and GPS-denied environments. The system universally handles different operating conditions by automatically switching between or combining GPS-based positioning, IMU-based dead reckoning, and road sign-based localization, ensuring sufficient accuracy for autonomous driving operations regardless of environmental conditions.
Data Source
AI summary
Systems and methodologies for determining validity of a location of a vehicle include obtaining a first location of the vehicle corresponding to a first time. A first RSU signal including an indication of a location of the first RSU is received at the vehicle from a first Roadside Unit (RSU). One or more location measurements are obtained of the vehicle relative thee first RSU based on one or more sensors of the vehicle. The first location of the vehicle is compared with the first RSU-based location of the vehicle.