Surveying Instrument Sunlight Interference Tracking Filter
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Solution Overview
Problem
Surveying instruments with tracking functions face issues when sunlight enters the field of view, leading to overcurrents and inability to track targets due to the need for prohibited areas, which can result in missed target tracking.
Innovation Solution
A surveying instrument equipped with a lens barrel unit, driving unit, imaging device, filter switching device, and control unit that uses a tracking guide light filter to direct the collimation axis towards the tracking guide light, allowing for selective filtering of wavelengths to prevent sunlight interference and maintain target tracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a prohibited area is provided to block sunlight, then sunlight interference is prevented, but target tracking capability deteriorates when target enters the prohibited area
Solution Approach 1:
The imaging device is divided into multiple imaging units, each with its own field of view. The prohibited area is segmented into multiple regions corresponding to different imaging units, allowing independent control of filter application for each unit. This enables the system to block sunlight in affected areas while maintaining tracking capability in unaffected areas.
Solution Approach 2:
The filter control unit dynamically switches filters based on real-time detection of sunlight position and target position. When sunlight enters a prohibited area, the corresponding filter is activated; when the target moves into a prohibited area but sunlight does not, tracking continues without filter interference. This dynamic adaptation resolves the contradiction between blocking sunlight and maintaining tracking reliability.
2Illumination intensity
If sunlight enters the field of view, then tracking guide light detection is improved, but overcurrent flows in light receiving element circuit causing tracking failure
Solution Approach 1:
Different filters with different wavelength transmission characteristics are assigned to different imaging units based on their specific field of view and sunlight exposure conditions. The filter control unit selectively activates filters only in imaging units where sunlight enters prohibited areas, maintaining high illumination intensity for tracking guide light detection in unaffected units while preventing overcurrent in affected units.
3Object-affected harmful factors
If a filter is disposed on optical axis to block sunlight, then sunlight interference is reduced, but tracking guide light transmission may be blocked
Solution Approach 1:
Multiple filters with different wavelength transmission parameters are provided, each optimized for specific conditions. The filter control unit selects and activates the appropriate filter based on the wavelength characteristics of both sunlight and tracking guide light in each imaging unit, changing filter parameters dynamically to block sunlight while maintaining tracking guide light transmission.
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
Enables effective tracking of targets by preventing sunlight interference and allowing the instrument to detect and follow tracking guide light even when sunlight is present, ensuring continuous operation and accurate target acquisition.
Implementation Method 1
one filter of the two filters is a tracking guide light filter configured to transmit only wavelengths in a predetermined range centered on a wavelength of the tracking guide light
Data Source
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AI summary
Provided is a surveying instrument having a tracking function with a measure against sunlight. A surveying instrument is provided which includes a lens barrel unit storing optical systems of a tracking unit and a distance-measuring unit, a driving unit configured to drive and rotate the lens barrel unit, an imaging device configured to image an image in front of the lens barrel unit, a filter switching device configured to make switching so that either of two filters is selectively disposed on an optical axis of the imaging device, and a control unit configured to, when the imaging device acquires an image including tracking guide light transmitted from an optical transmitter, analyze the image and operate an arrival direction of the tracking guide light, and control the driving unit so that a collimation axis of the lens barrel unit is directed toward the arrival direction of the tracking guide light, wherein one filter of the two filters is a tracking guide light filter configured to transmit only wavelengths in a predetermined range centered on a wavelength of the tracking guide light, and the filter switching device disposes the tracking guide light filter on the optical axis of the imaging device when the imaging device acquires the image.