GNSS Antenna Calibration via Error Impact Maps
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Solution Overview
Problem
The measurement accuracy of GNSS signals in vehicles is affected by group delay variations, antenna error impacts, and vehicle body surface characteristics, which can lead to erroneous positioning in autonomous driving applications.
Innovation Solution
A method for determining vehicle position by receiving GNSS signals while calibrating the GNSS receiving antenna using multiple antenna error impact maps, which account for vehicle characteristics and orientation, and applying correction values using a Kalman filter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If standard GNSS signal reception is used without calibration, then the system is simple and easy to operate, but positioning accuracy deteriorates due to antenna error impacts and vehicle body surface effects
Solution Approach 1:
The patent applies preliminary action by pre-calibrating the antenna error impact maps before actual GNSS signal reception. Multiple antenna error impact maps are generated in advance by rotating the vehicle and measuring GNSS signals at different orientations. These pre-computed correction maps are then stored and automatically applied during normal operation, eliminating the need for real-time complex calculations while maintaining high positioning accuracy.
Solution Approach 2:
The patent introduces intermediary elements in the form of antenna error impact maps that act as mediators between the raw GNSS signals and the final position calculation. These maps contain pre-computed correction values that compensate for antenna errors and vehicle body surface effects. The control unit uses these intermediary maps to adjust the measured signal parameters, thereby improving positioning accuracy without requiring complex real-time processing.
2Measurement precision
If multiple antenna error impact maps are used to compensate for vehicle characteristics, then positioning accuracy improves, but the complexity of data processing and filter operations increases
Solution Approach 1:
The patent implements feedback through the Kalman filter, which continuously processes the measured signal parameters and compares them with expected values. The filter uses the antenna error impact maps to generate correction values and applies feedback loops to iteratively refine the position estimation. This feedback mechanism allows the system to handle multiple error maps systematically, selecting and applying appropriate corrections while maintaining computational efficiency through optimized filter operations.
3Measurement precision
If calibration is performed to account for different paint types and vehicle body surfaces, then measurement accuracy improves, but the calibration process becomes more complex and time-consuming
Solution Approach 1:
The patent resolves this contradiction by performing the comprehensive calibration process in advance during the manufacturing or setup phase. Multiple antenna error impact maps are generated beforehand by rotating the vehicle through different orientations and recording GNSS signal characteristics. These pre-calibrated maps account for various paint types, colors, and body surface characteristics. During actual operation, the pre-computed maps are simply selected and applied based on the current vehicle orientation, reducing calibration time to near-zero while maintaining high measurement accuracy.
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 method improves the positioning accuracy and overall performance of GNSS-based navigation in vehicles by compensating for systematic errors caused by vehicle body surfaces and orientations, achieving centimeter-level accuracy required for autonomous driving.
Implementation Method 1
A global navigation satellite system (Abbrev.: GNSS) has a number of GNSS satellites that move around the earth and emit electromagnetic GNSS signals. By receiving GNSS signals with an antenna...
Implementation Method 2
performing the position determination with a Kalman filter, wherein corrective values determined in step c) are considered
Data Source
AI summary
A method is disclosed for determining position in a vehicle by receiving GNSS signals while calibrating a GNSS receiving antenna based on a plurality of different antenna error impact maps stored in the vehicle. The method includes (a) determining at least one signal parameter of at least one GNSS signal, (b) selecting at least two antenna error impact maps from the plurality of antenna error impact maps, (c) determining at least one correction value to correct a position determination from each of the at least two selected antenna error impact maps while taking into account the signal parameter determined in step (a), and (d) performing the position determination with a Kalman filter, wherein corrective values determined in step (c) are taken into account.