Optical Angle Encoder Compensation for Geodetic Surveying Precision
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Solution Overview
Problem
Geodetic surveying instruments suffer from mechanical imperfections and environmental influences that cause measurement errors, requiring complex and time-consuming calibration procedures to maintain precision, which are not effective in real-world conditions.
Innovation Solution
Implement a geodetic surveying instrument with optical angle encoders that capture images of a code carrier using non-collimated light, allowing for the determination of target direction and distance by evaluating code images considering all six degrees of freedom, including rotational and translational movements, to compensate for axis misalignments and deformations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex calibration procedures are implemented to maintain measurement precision, then measurement precision is improved, but time consumption and operational complexity increase
Solution Approach 1:
The system performs self-calibration by automatically detecting axis misalignments and computing correction values without requiring external calibration equipment or procedures. The angle encoders continuously monitor the positions of the first and second axes, and the controller automatically determines correction values to compensate for misalignments, enabling the instrument to maintain precision through self-service calibration
Solution Approach 2:
The system implements feedback by continuously monitoring the actual positions of the rotation axes using angle encoders and comparing them against ideal positions. The controller uses this feedback information to automatically compute and apply correction values, creating a closed-loop system that maintains measurement precision through continuous self-adjustment without requiring external calibration
2Measurement precision
If complex calibration procedures are implemented to maintain measurement precision, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The system eliminates the need for external calibration equipment and complex calibration procedures by implementing self-service calibration. The angle encoders and controller work together to automatically detect misalignments and compute correction values, simplifying the overall system while maintaining precision through automated self-calibration capabilities
Solution Approach 2:
The system replaces complex mechanical calibration procedures with an automated electronic system. Angle encoders electronically monitor axis positions, and the controller computationally determines correction values, substituting mechanical calibration complexity with electronic sensing and computational processing that simplifies the overall device architecture
3Device complexity
If traditional angle encoders are used that only measure rotational position, then device simplicity is maintained, but measurement precision deteriorates due to inability to compensate for axis misalignments
Solution Approach 1:
The system transitions from traditional single-dimensional rotational position measurement to multi-dimensional measurement by adding angle encoders that measure both the first and second rotation axes simultaneously. This dimensional expansion enables the system to detect axis misalignments and apply corrections in multiple directions, improving measurement precision without excessive complexity
Solution Approach 2:
The angle encoder system serves multiple functions: it measures rotational position, detects axis misalignments, and provides data for computing correction values. This multi-functionality allows the same hardware components to address multiple measurement challenges, improving precision while maintaining reasonable device complexity
4Adaptability or versatility
If the instrument is used in tilted positions to increase adaptability, then adaptability is improved, but measurement precision deteriorates due to gravity-induced deformations
Solution Approach 1:
The system compensates for gravity-induced deformations by dynamically adjusting measurement parameters based on the instrument's orientation. The angle encoders detect changes in axis positions caused by tilting, and the controller computes correction values that account for gravitational effects, allowing the instrument to maintain precision across a range of operational positions and orientations
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 reduces measurement effort and calibration time while maintaining precision, enabling accurate surveying even in tilted positions and compensating for environmental influences, and provides health monitoring for instrument maintenance.
Implementation Method 1
having a code carrier and one or multiple image sensors for capturing an image of code of the code carrier, using non-collimated light
Data Source
Figure 1~2
Figure 3a~3e
Figure 4a~4c
AI summary
A geodetic surveying instrument (1) comprising a sighting unit (23) for aiming in a target direction (t) at a measurement target point, a defined axis of rotation for setting the target direction (t) by rotation about the axis (v, h), an optical angle encoder (2) for determining the target direction (3), having a code carrier (3) and at least one image sensor (4) for capturing an image of code -denoted code image (11)- of the code carrier (3), whereby the code carrier (3) and image sensor (4) are rotatable relative to one another about the defined axis of rotation (v) as a first degree of freedom. The controller (25) is configured to determine the target direction (t) based on evaluation of a code image (11) of the image sensor (4). The target direction (t) is determined not only with respect to a rotational position in said first degree of freedom of code carrier (3) relative to image sensor (4) but also with respect to a further position in at least a further degree of freedom of code carrier (3) relative to image sensor (4).