Vehicle Positioning With Pseudo-Range, Doppler, And Motion Constraints
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Solution Overview
Problem
Existing vehicle positioning systems face challenges in maintaining accuracy in weak satellite signal scenarios, leading to positioning drift and errors, particularly in environments with dense tall buildings or bad weather conditions.
Innovation Solution
Utilizing pseudo range observation values and Doppler observation values based on satellite ephemeris to enhance satellite positioning accuracy by updating satellite filtering parameters and constructing motion state constraints, thereby improving vehicle positioning information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional GPS positioning is used in weak satellite signal scenarios, then the positioning system can operate in all environments, but the positioning accuracy deteriorates due to signal weakness and drift
Solution Approach 1:
The patent combines multiple positioning data sources (GPS pseudo-range observations, Doppler observations, and inertial navigation data) into a unified positioning system. By merging these different data sources and processing them together through a joint optimization algorithm, the system achieves reliable positioning in weak signal scenarios while maintaining accuracy through the complementary strengths of each data source.
Solution Approach 2:
The patent creates a composite positioning solution by integrating multiple positioning technologies (satellite-based GPS and inertial navigation) into a hybrid system. This composite approach allows the system to leverage the global coverage of GPS and the continuous accuracy of inertial navigation, achieving both reliability and precision that neither system could provide alone in weak signal environments.
2Speed
If satellite positioning data is continuously updated without filtering, then the positioning system responds quickly to position changes, but positioning accuracy deteriorates due to data drift and noise
Solution Approach 1:
The patent applies preliminary filtering and validation actions to satellite positioning data before it is used for position calculation. By pre-processing the data to remove obvious errors and drift through filtering algorithms, the system maintains both fast update speed and high accuracy, as the filtering prepares the data in advance without adding significant processing delay.
Solution Approach 2:
The patent implements a feedback mechanism where positioning results are continuously evaluated and used to adjust the filtering parameters and data selection criteria. This feedback loop allows the system to maintain optimal balance between update speed and accuracy by adapting the filtering strength based on the actual quality of incoming satellite data and the vehicle's motion state.
3Measurement precision
If state constraint is applied based on historical positioning data, then positioning accuracy is improved in stationary states, but the system complexity increases due to additional processing requirements
Solution Approach 1:
The patent implements dynamic state constraint processing where the level of filtering and constraint application is automatically adjusted based on the detected motion state of the vehicle. When the vehicle is stationary, stronger constraints are applied to improve accuracy; when moving, the constraints are relaxed to allow faster response. This dynamic adaptation reduces unnecessary processing complexity while maintaining accuracy where needed.
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
Enhances the reliability and accuracy of vehicle positioning in weak satellite signal scenarios by leveraging the higher reliability of pseudo range and Doppler observation values, and incorporating vehicle motion state constraints to correct positioning information.
Implementation Method 1
a Doppler observation value indicating a Doppler effect of a signal of the satellite
Data Source
AI summary
A vehicle positioning method includes obtaining satellite filtering parameters and satellite data, the satellite data comprising at least one of (i) a pseudo range observation value or (ii) a Doppler observation value indicating a Doppler effect. The method further includes determining a first parameter correction amount corresponding to the vehicle at a first time point to obtain positioning information of the vehicle at the first time point. The method further includes determining a second parameter correction amount corresponding to the vehicle at the second time point according to a constraint matrix corresponding to the motion state of the vehicle, and obtaining positioning information of the vehicle at the second time point by modifying the positioning information at the first time point using the second parameter correction amount.