Magnetic Landmark Vehicle Localization in GPS-Denied Areas
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Solution Overview
Problem
Current outdoor location-based systems for road vehicles face limitations in multipath environments and non-line-of-sight satellite conditions, with inertial sensors experiencing cumulative errors, and geomagnetic-field information being distorted by road infrastructure, leading to inefficiencies in vehicle localization.
Innovation Solution
A method and system utilizing magnetic landmarks, which leverage opportunistic distortions in the geomagnetic field created by road infrastructure to improve localization accuracy, by creating a reference landmark database during an offline phase and matching detected anomalies in real-time during an online phase, using a sensor unit, processing unit, and storage unit connected via a bidirectional communication link.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If satellite-based localisation is used for road vehicles, then coverage area is large and infrastructure deployment is minimal, but position errors increase in multipath environments and non-line-of-sight conditions
Solution Approach 1:
The patent segments the localisation problem into two complementary systems: satellite-based GPS for broad coverage and magnetic field-based localisation for precision in challenging environments. The magnetic sub-system is activated specifically when satellite signals are unavailable or unreliable, creating a segmented approach that optimizes both coverage and accuracy.
Solution Approach 2:
The patent introduces magnetic field anomalies as intermediary landmarks that mediate between the vehicle and the localisation system. These magnetic landmarks, created by road infrastructure, serve as intermediate reference points that the vehicle can detect and use for positioning when direct satellite observation is blocked.
2Reliability
If inertial sensors are used for dead reckoning, then localisation can work during GPS outages, but cumulative errors increase over time
Solution Approach 1:
The patent implements feedback by using magnetic landmarks to periodically correct and reset the cumulative errors of inertial dead reckoning. When a magnetic landmark is detected, the system compares the inertially-derived position with the known landmark position and applies a correction, preventing error accumulation over time.
Solution Approach 2:
The patent performs preliminary action by pre-mapping magnetic landmarks along road routes before vehicles traverse them. This offline phase creates a database of magnetic field signatures at known locations, which are then used during online vehicle operation to provide reference points for correcting inertial navigation drift.
3Reliability
If continuous magnetic fingerprinting is used for outdoor vehicle localisation, then localisation can be provided in GPS-denied environments, but computational requirements and mapping effort increase significantly
Solution Approach 1:
The patent extracts only the essential magnetic field features from the environment—specifically, magnetic anomalies caused by road infrastructure—rather than attempting to fingerprint the entire magnetic environment. This selective extraction reduces the data volume and computational complexity while maintaining localisation effectiveness.
Solution Approach 2:
The patent applies partial action by using magnetic landmarks only at specific critical points along the route rather than continuous magnetic fingerprinting. This approach provides sufficient localisation capability with reduced mapping and computational effort compared to comprehensive continuous fingerprinting.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach provides accurate and reliable location information, reducing computational requirements and enhancing localization accuracy in areas where satellite-based systems are limited, such as tunnels and urban canyons, by focusing on magnetic anomalies as landmarks, thereby supporting existing localization systems like GPS.
Implementation Method 1
measuring the geomagnetic field is widely applied in dead reckoning for orientation estimation
Implementation Method 2
the steel and other materials found in structures of buildings, which interacts with the Earth's magnetic field creating distortions
Data Source
AI summary
The present invention relates to a road vehicle localisation method based on magnetic landmarks. Said method is comprised by an offline phase and by an online phase. The offline phase is responsible for creating a reference landmark database comprised by a plurality of magnetic landmarks, wherein each magnetic landmark is associated to a path location data. The online phase is projected to match a current anomaly detected with a reference anomaly of the reference landmark database, in order to estimate the location of a vehicle based on the path location data of the correspondent reference landmark.It is also described a system comprised by a sensor unit, a storage unit and by a processing unit, which is specifically programmed to operate according the road vehicle localisation method developed.