Total Station Tilt Angle Calculation During Rapid Rotation
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Solution Overview
Problem
Surveying devices, such as total stations, face decreased measurement accuracy when rapidly rotating due to viscosity-dependent delays, centrifugal force-induced inclinations, and surface shape changes in liquid-based tilt sensors, which also affect responsiveness and accuracy.
Innovation Solution
A surveying device incorporating a rotating unit with a horizontal rotation angle sensor and a tilt sensor, where the tilt is calculated using an X and Y component formula based on initial and post-rotation measurements, and optionally corrected with additional tilt sensor data from a support, to maintain accuracy during horizontal rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a liquid-based tilt sensor is used to measure tilt angle, then high accuracy and reliability are achieved in static conditions, but measurement accuracy decreases during rapid rotation due to viscosity-dependent delays, centrifugal force-induced inclinations, and surface shape changes
Solution Approach 1:
The patent replaces the mechanical liquid-based tilt sensor system with an optical-based measurement system. The optical axis orientation sensor measures tilt angles using optical principles rather than liquid surface behavior, eliminating the harmful effects of viscosity, centrifugal force, and surface tension that plague liquid-based sensors during rapid rotation.
Solution Approach 2:
The patent introduces an intermediary calculation system that uses the relationship between horizontal rotation angle and tilt angle to compute the tilt angle after rotation. By using the formula that relates initial tilt angle, horizontal rotation angle, and final tilt angle, the system indirectly determines the accurate tilt angle without relying on direct liquid surface measurement during rotation.
2Stability of the object's composition
If an averaging process is applied to reduce liquid surface fluctuation, then measurement stability improves, but responsiveness and measurement accuracy decrease
Solution Approach 1:
The patent substitutes the liquid-based measurement system with an optical measurement system that provides immediate response. The optical axis orientation sensor and horizontal rotation angle sensor provide real-time data without the inertia and delay characteristics of liquid surfaces, eliminating the need for averaging processes that sacrifice responsiveness.
Solution Approach 2:
The patent performs preliminary measurement of the horizontal rotation angle and uses it to calculate the tilt angle after rotation before any fluctuation or delay can occur. By calculating the expected tilt angle based on the measured horizontal rotation and initial tilt angle, the system provides immediate accurate results without waiting for liquid surface stabilization.
3Measurement precision
If additional sensors and calculation units are added to compensate for rotation effects, then tilt angle measurement accuracy during rotation is maintained, but device complexity increases
Solution Approach 1:
The patent makes the optical axis orientation sensor serve multiple functions: it measures both the initial tilt angle and the tilt angle after rotation, while the horizontal rotation angle sensor measures rotation. This multi-functionality reduces the need for separate dedicated sensors for each measurement task, thereby limiting the increase in device complexity.
Solution Approach 2:
The patent uses the horizontal rotation angle as a proxy to calculate the change in tilt angle. Instead of directly measuring the complex liquid surface behavior during rotation, the system copies the rotational information and uses mathematical relationships to derive the tilt angle, simplifying the measurement approach.
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 configuration enhances the accuracy of tilt angle measurement by compensating for the limitations of liquid-based tilt sensors during rapid rotations, ensuring high responsiveness and precision, especially when tracking moving targets like UAVs.
Implementation Method 1
A tilt sensor with a mechanism for optically measuring tilt of a liquid surface is publicly known
Implementation Method 2
an inclination generated by centrifugal force, a change in shape of the liquid surface by acceleration
Implementation Method 3
a liquid (normally, oil) viscosity-dependent delay that causes low followability
Data Source
AI summary
A technique for preventing decrease in accuracy of measuring a tilt angle of a surveying device is provided. A total station includes a rotating unit, a horizontal angle measuring unit, a tilt sensor, and a tilt amount calculating part. The rotating unit has a distance measuring unit that performs optical surveying, and the rotating unit horizontally rotates. The horizontal angle measuring unit measures a rotation angle of the horizontal rotation of the rotating unit. The tilt sensor measures a tilt of the rotating unit relative to the direction of gravity. The tilt amount calculating part calculates a tilt of the rotating unit on the basis of measured values of the horizontal angle measuring unit before and after the rotating unit rotates.