Tracker Unit Non-Coaxial Optics for Surveying Alignment
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Solution Overview
Problem
Coaxial optic configurations in tracking systems for surveying devices are costly and prone to optical errors such as crosstalk and non-homogeneous laser beams, which affect the accuracy of target alignment.
Innovation Solution
A tracker unit employing a non-coaxial optic configuration with two eccentrically arranged optical radiation sources, which simulate a coaxial behavior by compensating for angular errors using a compensation table or function, allowing precise alignment of the instrument sighting axis with the target axis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a coaxial optic configuration is employed in the tracker unit, then the alignment accuracy and beam focus are improved, but the device cost and optical errors (crosstalk, shadows) increase
Solution Approach 1:
The patent divides the optical system into separate transmitter and receiver paths with non-coaxial arrangement. The transmitter optic and receiver optic are spatially segmented and positioned at different locations, eliminating the need for a complex coaxial configuration while maintaining functional effectiveness.
Solution Approach 2:
The patent uses a collimation element that creates a virtual image of the laser source at a different location. This copying approach allows the optical system to function as if coaxial while physically being non-coaxial, reducing complexity and cost while maintaining alignment accuracy.
2Manufacturing precision
If a coaxial optic configuration is employed in the tracker unit, then the beam focus is improved, but optical errors such as crosstalk and shadows increase
Solution Approach 1:
The patent extracts the harmful elements (shadows, crosstalk) by removing the coaxial configuration that causes them. The receiver optic is positioned separately from the transmitter path, taking out the source of optical errors while maintaining the necessary beam focusing capability through the collimation element.
Solution Approach 2:
The collimation element acts as an intermediary that creates a virtual image of the laser source. This intermediary structure enables the beam to be properly focused and directed without requiring the receiver to be positioned in the direct transmitter path, thereby eliminating shadows and crosstalk.
3Device complexity
If a non-coaxial optic configuration is employed in the tracker unit, then the device cost and optical errors are reduced, but the alignment precision may deteriorate
Solution Approach 1:
The collimation element creates a virtual copy of the laser source at a specific location, allowing the non-coaxial receiver to accurately measure the beam direction. This virtual copying maintains alignment precision despite the physical separation of transmitter and receiver optics.
Solution Approach 2:
The patent changes the spatial parameters of the optical system by positioning the transmitter and receiver at different locations with specific angular relationships. The collimation element adjusts the beam parameters to ensure accurate alignment measurement despite the non-coaxial configuration.
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 costs and minimizes optical errors, enabling accurate and efficient target alignment in surveying applications while maintaining the functionality of coaxial configurations.
Implementation Method 1
optical radiation impinging on the photosensors generated by reflection of optical radiation emitted by the first optical radiation source
Implementation Method 2
photosensor module comprising an optical system and a plurality of photosensors. Each photosensor is adapted to generate a signal corresponding to intensity of optical radiation impinging on the photosensor
Data Source
AI summary
A tracker unit for a measuring instrument such as a total station is disclosed. The tracker unit comprises a first and at least a second optical radiation source arranged at different positions and each of which is noncoaxially arranged with respect to a tracker pointing axis and adapted to emit optical radiation towards the reflective target when activated. The first and the at least a second optical radiation source are arranged at such positions so that the tracker pointing axis and the position of the first optical radiation source define a first plane and the tracker pointing axis and the position of the at least a second optical radiation source define a second plane, such that the first optical radiation source is coaxial with respect to the tracker pointing axis in a plane perpendicular to the first plane and the at least a second optical radiation source is coaxial with respect to the tracker pointing axis in a plane perpendicular to the second plane. At least one first set of signals is generated on basis of optical radiation impinging on the photosensors generated by reflection of optical radiation emitted by the first optical radiation source. At least one second set of signals is generated on basis of optical radiation impinging on the photosensors generated by reflection of optical radiation emitted by the at least one second optical radiation source. By employing the at least two optical radiation sources in the tracker unit that are eccentrically arranged with respect to the tracker pointing axis, a non-coaxial optic configuration may be employed in the tracker unit while at the same time allowing for a coaxial optic behavior in the tracker unit to be mimiced or ‘simulated’.