Vehicle Navigation Heading Calibration on Uneven Terrain
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Solution Overview
Problem
Current navigation systems for terrestrial vehicles, such as tractors and mining vehicles, face accuracy issues due to discrepancies between the location of the GNSS receiver and the point of interest on the vehicle, especially when traversing uneven terrain or experiencing pitch and roll.
Innovation Solution
The method involves receiving position signals from a GNSS antenna and gyro signals from gyro sensors to determine the compensated position of a point of interest on the vehicle. This position is corrected for pitch and roll, and a calibrated heading direction is calculated by combining gyro-based and position-based heading directions. A control signal is then generated to guide the vehicle along a desired path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GNSS antenna is mounted at a fixed location on the vehicle, then the navigation system can receive position signals, but the position of the point of interest cannot be accurately determined when the vehicle experiences pitch and roll on uneven terrain
Solution Approach 1:
The patent combines GNSS position data with inertial measurement unit (IMU) data that captures pitch and roll information. By merging these two data sources, the system compensates for the displacement between the GNSS antenna and the point of interest, achieving accurate position determination without requiring additional antennas at every possible point of interest.
Solution Approach 2:
The patent introduces an intermediary computational model that calculates the relative position between the GNSS antenna and the point of interest based on vehicle pitch and roll angles. This intermediary calculation acts as a bridge, translating GNSS antenna positions into accurate point of interest positions even when the vehicle is on uneven terrain.
2Measurement precision
If the navigation system uses only GNSS position data, then the system is simpler, but the heading direction accuracy deteriorates when the vehicle orientation changes
Solution Approach 1:
The patent merges GNSS-derived heading information with IMU-derived heading information to create a calibrated heading direction. This combination leverages the strengths of both sensors: GNSS provides absolute orientation reference while IMU provides continuous orientation tracking, resulting in more accurate heading determination than either sensor alone.
Solution Approach 2:
The patent implements a feedback mechanism where the system continuously compares and reconciles GNSS position data with IMU orientation data to calibrate the heading direction. This feedback loop ensures that the heading accuracy is maintained by constantly adjusting for discrepancies between the two data sources.
3Measurement precision
If the GNSS antenna is located away from the point of interest, then the antenna can be mounted in a stable location, but the navigation accuracy to the point of interest decreases
Solution Approach 1:
The patent uses an intermediary computational approach that calculates the offset between the GNSS antenna and the point of interest based on vehicle orientation. This intermediary calculation allows the system to mount the antenna in a convenient, stable location while still achieving accurate navigation to the point of interest through mathematical compensation.
Solution Approach 2:
The patent changes the parameter being measured from the absolute antenna position to the relative point of interest position by incorporating pitch and roll angle corrections. This parameter transformation allows the system to maintain accurate navigation despite the physical separation between the antenna and the point of interest.
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 enhances the accuracy of terrestrial vehicle navigation by compensating for errors caused by terrain irregularities and vehicle orientation, ensuring that the point of interest follows the desired path.
Implementation Method 1
receiving a gyro signal from a gyro sensor that is indicative of: (i) at least one of a pitch and a roll of the terrestrial vehicle
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
A method for guiding a terrestrial vehicle along a desired path can include receiving a position signal from a global navigation satellite system (GNSS) antenna and a gyro signal from a gyro sensor that is indicative of: (i) at least one of a pitch and a roll of the terrestrial vehicle, and (ii) a gyro-based heading direction. A position of a point of interest of the terrestrial vehicle at a location different from the GNSS antenna can be determined based on the position signal, the gyro signal, and a positional relationship between the GNSS antenna location and the location of the point of interest. A position-based heading direction of the point of interest of the terrestrial vehicle can be determined based on the determined position of the point of interest and at least one previously determined position of the point of interest. A calibrated heading direction can be determined based on a combination of the gyro-based heading direction and the position-based heading direction.