Inertial Navigation System Augmentation for Earthmoving
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Solution Overview
Problem
Existing position monitoring systems for earthmoving machines, such as GPS and laser systems, provide inaccurate elevation information and update frequencies that are not sufficient for real-time automatic control of implements like bulldozer blades, leading to unacceptable errors over time.
Innovation Solution
An inertial navigation system (INS) is integrated with a processor and a valve controller, which compares position information from the INS with a desired vertical position and adjusts the implement accordingly, while being periodically reset using error estimates from external measuring devices like GPS, lasers, and total stations to maintain accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If satellite positioning systems (GPS) are used to detect position information, then the system can provide position data, but the update frequency is insufficient (0.1-100 Hz, typically 10-20 Hz) and elevation accuracy is poor for real-time automatic control
Solution Approach 1:
The patent combines an inertial navigation system (INS) with satellite positioning systems and/or laser systems to create a hybrid positioning system. The INS provides high-frequency position data (greater than 100 Hz) while external systems provide periodic corrections to maintain accuracy, resolving the contradiction between update frequency and measurement precision.
Solution Approach 2:
The inertial navigation system acts as an intermediary between external positioning systems and the automatic control system. It receives low-frequency corrections from GPS or laser systems and transforms them into high-frequency position information suitable for real-time control, bridging the gap between update rates and control requirements.
2Measurement precision
If automatic total station (ATS) systems are used to determine position, then position data can be obtained, but the update rate is limited (up to 6 Hz) which is insufficient for real-time control applications
Solution Approach 1:
The patent merges the ATS system with an inertial navigation system. The INS continuously tracks position at high frequency while the ATS provides periodic absolute position references, combining the high update rate of INS with the accuracy of ATS to overcome the update rate limitation of ATS alone.
3Speed
If inertial navigation system alone is used to provide position information, then high update frequency (greater than 100 Hz) is achieved, but position accuracy deteriorates over time due to error accumulation
Solution Approach 1:
The patent implements a feedback mechanism where external positioning systems (GPS, laser, or ATS) periodically measure the actual position and provide correction signals to the INS. This feedback resets the INS error accumulation, maintaining long-term accuracy while preserving the high update frequency capability of the INS.
Solution Approach 2:
The system uses periodic corrections from external positioning systems at predetermined time intervals to reset the inertial navigation system. This periodic action prevents error accumulation in the INS while maintaining its high-frequency output, resolving the contradiction between update frequency and accuracy over time.
4Productivity
If high-frequency position updates are required for real-time control, then response time is improved, but system complexity increases when integrating multiple positioning systems
Solution Approach 1:
The patent designs the inertial navigation system to serve multiple functions: it provides high-frequency position data for real-time control, acts as an intermediary to integrate external positioning systems, and performs error correction. This multi-functionality reduces the need for separate systems and simplifies overall system architecture despite the integration of multiple positioning technologies.
Data Source
AI summary
Systems and methods for augmenting an inertial navigation system (INS) include outputting from the INS position information associated with the implement and adjusting the implement based upon a comparison of the position information of the implement and a desired position of the implement. The INS is periodically re-initialized using error estimates generated by a kalman filter as a function of position information from one or more positioning (or measuring) devices, such as a fan laser, an automatic total station (ATS), a GNSS receiver, or a ground based radio positioning system, to correct a drift of the position information that may be caused by inherent characteristics of the INS.