Inertial Sensor Misalignment Correction via GPS Self-Surveying
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Solution Overview
Problem
Traditional precision navigation systems face challenges in sensor installation, including time-consuming and costly manual surveying processes, difficulty in achieving stringent angular alignment, and the need for frequent recalibration due to platform flexure, which can lead to inaccurate navigation data and safety hazards.
Innovation Solution
The Real-Time Sensor Installation Monitor (RSIM) algorithm utilizes high-integrity differential GPS processing to automatically align navigation sensors, perform self-surveying, verify survey accuracy, and monitor platform flexure, ensuring ultra-high accuracy and integrity in sensor placement and orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual surveying processes are used for sensor installation, then survey accuracy can be achieved, but the process is time-consuming and costly
Solution Approach 1:
The system performs self-surveying by automatically determining sensor positions and orientations using GPS signals and inertial measurements without requiring external surveyors. The sensors autonomously calculate their own installation parameters and monitor their own alignment status, eliminating the need for manual surveying operations while maintaining high accuracy standards.
Solution Approach 2:
The patent replaces manual mechanical surveying operations with an automated electronic system combining GPS receivers, inertial measurement units, and computational algorithms. This substitution eliminates the need for physical surveying equipment and human operators, dramatically reducing installation time while preserving measurement precision through sophisticated signal processing and error correction.
2Manufacturing precision
If manual alignment methods are used, then angular alignment can be achieved, but it is difficult to meet stringent requirements
Solution Approach 1:
The system continuously monitors sensor alignment status by comparing measured positions and orientations against predetermined thresholds. When misalignment is detected, the system generates alerts and can automatically initiate correction procedures, providing real-time feedback that ensures stringent angular alignment requirements are met without requiring complex manual adjustment processes.
Solution Approach 2:
The alignment system transitions from static manual adjustment to dynamic automated monitoring and correction. The sensors continuously track their own positions and orientations, automatically adapting to environmental changes and platform movements, thereby achieving and maintaining precise angular alignment without the complexity of manual realignment procedures.
3Reliability
If frequent recalibration is performed to account for platform flexure, then navigation accuracy is maintained, but system productivity decreases
Solution Approach 1:
The system performs continuous monitoring of sensor positions and platform flexure without interruption to navigation operations. Rather than stopping for periodic recalibration, the sensors continuously track their own status and automatically compensate for platform movements, maintaining navigation accuracy while eliminating downtime and maximizing system productivity.
Solution Approach 2:
The patent replaces manual recalibration operations with automated electronic monitoring and computational compensation. The system uses GPS and inertial data to continuously calculate and correct for platform flexure effects, eliminating the need for physical recalibration interventions and maintaining high navigation accuracy without sacrificing operational efficiency.
4Productivity
If automated alignment systems are implemented, then installation time is reduced, but system complexity increases
Solution Approach 1:
The automated system combines multiple functions into integrated sensor units that simultaneously perform position tracking, orientation measurement, alignment verification, and error correction. This multi-functionality reduces the need for separate specialized equipment and simplifies the overall system architecture, achieving fast installation without proportionally increasing complexity.
Solution Approach 2:
The patent merges GPS receivers, inertial measurement units, and alignment monitoring algorithms into integrated sensor systems. This consolidation eliminates the need for multiple separate components and interfaces, reducing system complexity while maintaining the automated alignment capabilities that enable rapid installation.
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
RSIM significantly reduces the time and labor required for sensor installation and maintenance, providing high-integrity navigation data with less than 1×10−7 likelihood of faulty solutions, enhancing safety and efficiency in precision navigation systems.
Implementation Method 1
Each local reference receiver can measure a time of transmission between a GPS satellite and the local reference receiver and a travel distance of the GPS signal
Data Source
AI summary
Technology for correcting a misalignment between an inertial measurement unit (IMU) and a moving platform is described. A first attitude of the moving platform can be identified based on a truth source. A second attitude of the moving platform can be calculated using IMU measurements. A delta attitude can be calculated from a difference between the first attitude and the second attitude. Natural error can be removed from the delta attitude to produce an angular misalignment value between axes of the IMU and axes of the moving platform. A total misalignment value can be determined by adding the angular misalignment value to a baseline misalignment value. The IMU can incorporate the total misalignment value for subsequent attitude measurements of the moving platform in order to produce substantially accurate attitude measurements of the moving platform when the axes of the IMU are misaligned with the axes of the moving platform.