Optical Tracking Vehicle Control System for GNSS Outages
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Solution Overview
Problem
Existing automatic steering systems for agricultural and mining vehicles face challenges due to limitations in GNSS signal reception rates and errors introduced by inexpensive inertial sensors, particularly during prolonged GNSS outages or in adverse weather conditions.
Innovation Solution
A control system that incorporates an optical movement sensor to scan the surface beneath the vehicle, providing high-frequency position and heading data to a controller, which can compensate for errors in inertial sensors and operate independently of GNSS signals, using a combination of optical and inertial sensors to maintain accurate vehicle tracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GNSS-based systems are used to determine vehicle location, then the system can provide location data, but the location is determined at a relatively low rate causing significant periods where location is not being determined
Solution Approach 1:
The patent combines GNSS receiver with inertial sensors (accelerometers and gyroscopes) to create a hybrid navigation system. The inertial sensors continuously track vehicle motion between GNSS updates, filling the gaps in location determination and providing high-rate position data without relying solely on periodic GNSS signals.
Solution Approach 2:
The inertial sensors act as an intermediary between GNSS updates, continuously estimating vehicle position and orientation during periods when GNSS location is not being determined. This intermediary system bridges the time gaps in GNSS data delivery.
2Ease of manufacture
If inexpensive inertial sensors are used to control steering, then the system cost is reduced, but time-varying errors are introduced particularly during prolonged GNSS outages
Solution Approach 1:
The system uses feedback from both GNSS receiver and inertial sensors to continuously monitor and correct steering control. During normal operation, GNSS provides absolute position reference to correct drift in inertial sensors. During GNSS outages, the inertial sensors continue providing relative motion data, and the feedback loop maintains steering accuracy within acceptable bounds.
Solution Approach 2:
The patent creates a composite sensing system combining GNSS receiver with inexpensive inertial sensors. This composite approach allows the use of lower-cost individual components while achieving reliable overall performance through the complementary strengths of each sensor type.
3Device complexity
If GNSS-only systems are used for automatic steering control, then the system is simpler, but the vehicle often deviates from the desired path of travel
Solution Approach 1:
The patent merges GNSS-based positioning with inertial navigation to create a more robust path following system. The combination provides continuous high-rate position and orientation data, enabling the vehicle to maintain accurate path following without the deviations experienced with GNSS-only systems.
Data Source
AI summary
An optical tracking vehicle control system includes a controller adapted for computing vehicle guidance signals and a guidance subsystem adapted for receiving the guidance signals from the controller and for guiding the vehicle. An optical movement sensor is mounted on the vehicle in optical contact with a travel surface being traversed by the vehicle. The optical movement sensor is connected to the controller and provides vehicle movement signals thereto for use by the controller in computing vehicle position. The optical movement sensor can be either mounted on a gimbal for movement independent of the vehicle, or, alternatively, multiple optical movement sensors can be provided for detecting yaw movements. GNSS and inertial vehicle position tracking subsystems are also provided. Still further, a method of tracking a vehicle with an optical movement sensor is provided.