GNSS Error Correction for Tilted Working Vehicles
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Solution Overview
Problem
The accuracy of automatic steering control in working vehicles is compromised due to errors generated by the GNSS sensor when the vehicle tilts in rugged farm fields, as the sensor is mounted at a high location, leading to inaccuracies in position measurement.
Innovation Solution
An error correcting device that uses a combination of a GNSS sensor and a gyro sensor to acquire vehicle position and angular velocity, performing coordinate transformations to correct the measured position and velocity vectors, reducing errors caused by the sensor's high mounting position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the GNSS sensor is mounted at a high location (upper end portion of arm or roof portion) to improve signal reception, then the GNSS signal reception is improved, but the position measurement accuracy deteriorates when the vehicle tilts on rugged terrain
Solution Approach 1:
The patent introduces a roof portion attitude detection device (gyro sensor, acceleration sensor) as an intermediary to detect the tilt state of the vehicle body. This intermediary measurement is then used to calculate and correct the position measurement error, thereby resolving the contradiction between maintaining high sensor mounting for signal reception and ensuring position accuracy on uneven terrain
Solution Approach 2:
The system implements feedback by continuously monitoring the vehicle's tilt angle through attitude detection sensors and using this information to dynamically correct the GNSS position measurements. The correction amount is calculated based on the detected attitude and fed back to adjust the final position data, thereby compensating for the error introduced by high mounting position
2Stability of the object's composition
If the GNSS sensor is mounted high on the vehicle to ensure stable signal reception, then signal reception stability is improved, but the error between measured position and actual vehicle position increases on uneven terrain
Solution Approach 1:
The attitude detection device serves as an intermediary that measures the vehicle's tilt state without interfering with the GNSS signal reception. This intermediary measurement enables the system to understand the geometric relationship between the high-mounted sensor and the actual vehicle position, allowing for accurate compensation
Solution Approach 2:
The patent replaces the need for mechanical repositioning or physical adjustment of the sensor with a computational correction system. Instead of mechanically moving the sensor to different positions, the system uses mathematical calculations based on attitude detection to substitute for the physical position discrepancy
Data Source
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AI summary
An error correcting device 34 is mounted in a working vehicle and corrects an error in measurement value of a sensor device having a GNSS sensor and a gyro sensor. The error correcting device 34 includes: a first acquisition part 341 that acquires a vehicle position of the working vehicle in a local coordinate system, the vehicle position being measured by the GNSS sensor, and an angular velocity in a sensor coordinate system having three axes set with reference to the sensor device, the angular velocity being measured by the gyro sensor; a coordinate transformation part 345 that coordinate-transforms, based on the acquired angular velocity, a relative position vector of a measurement position in the sensor coordinate system at which the sensor device is provided, the relative position vector extending from a set position set at a different position from the position of the sensor device in the sensor coordinate system, to a relative position vector in the local coordinate system; and a vehicle position correcting part 346 that calculates a position vector Pa of the set position extending from an origin of the local coordinate system according to an expression of Pa = Ps - L, wherein Ps denotes a position vector of the measurement position and L denotes the coordinate-transformed relative position vector, to correct an error in the vehicle position measured by the GNSS sensor.