Vehicle Localization Integrity Range for GNSS-Denied Urban Driving
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Solution Overview
Problem
Existing methods for determining the self-position of autonomous vehicles are not adequately reliable in urban environments due to challenges like street canyons interfering with satellite signals, and there is a need for improved estimation accuracy in feature-based localization.
Innovation Solution
A method for determining an integrity range of parameter estimation using sensor data from surroundings features, involving base and additional integrity information items, to provide a protection level for localization, which can be performed by a control unit in vehicles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GNSS signals are used as the primary data source for localization, then the localization system can provide protection level information, but the reliability deteriorates in urban areas with street canyons that interfere with satellite signals
Solution Approach 1:
The patent introduces an intermediary system consisting of surrounding feature sensors (cameras, radars, lidars) and a feature database that mediates between the vehicle and the localization task. When GNSS signals are blocked by street canyons, this intermediary system provides alternative localization through feature matching, thereby resolving the contradiction between maintaining reliability and avoiding signal interference.
Solution Approach 2:
The patent changes the fundamental parameter of localization from satellite-based coordinate matching to feature-based relative positioning. By transforming the localization approach from absolute GNSS coordinates to relative positions based on surrounding features, the system achieves reliable localization in urban environments where GNSS signals are blocked.
2Reliability
If feature-based localization is used to replace GNSS localization in urban areas, then the reliability in urban environments improves, but the ability to provide protection level information deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-storing three-dimensional information of surrounding features (buildings, bridges, overpasses) in a database before the vehicle reaches urban areas. This advance preparation enables the system to quickly perform feature matching and calculate protection levels when the vehicle enters GNSS-denied environments, thus resolving the contradiction between improving urban reliability and maintaining protection level information.
Solution Approach 2:
The patent implements beforehand cushioning by pre-acquiring and storing detailed three-dimensional feature data of the urban environment. This pre-stored information acts as a cushion that compensates for the lack of real-time GNSS signals, enabling the system to provide both reliable localization and protection level information during feature-based localization operations.
3Measurement precision
If multiple integrity information items are determined and combined, then the accuracy of the integrity range determination improves, but the device complexity increases
Solution Approach 1:
The patent segments the integrity assessment into distinct components: base integrity information from sensor data quality, additional integrity information from feature matching consistency, and environmental factors. By dividing the integrity assessment into these manageable segments, the system achieves high measurement precision while keeping the processing complexity manageable through modular computation.
Data Source
AI summary
A method is disclosed for determining an integrity range of a parameter estimation for localization of a vehicle on the basis of obtained sensor data for localization according to surroundings features, wherein the integrity range describes the range in which an estimated parameter is located with a minimum probability. The method includes (i) determining a base integrity information item, (ii) determining at least one additional integrity information item, and (iii) determining the integrity range using the base integrity information item and the at least one first additional integrity information item.