Surveying Instrument Target Tracking via Modulated Light Patterns
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Solution Overview
Problem
Conventional surveying instruments face challenges in maintaining accurate tracking of a desired target when another target appears within the field of view, leading to potential misidentification and continued tracking of the incorrect target.
Innovation Solution
The use of modulated light with different intensity patterns allows the surveying instrument to distinguish between light from the desired target and stray light, enabling precise control of the measuring unit's orientation through a combination of active and passive targets, utilizing a detector with multiple segments to process light intensity signals and generate control signals for actuators to maintain target tracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the surveying instrument uses a detector to automatically track targets, then the instrument can continuously perform measurements with moving targets, but the instrument may mistakenly track a second target instead of the first target when both appear within the field of view
Solution Approach 1:
The patent applies parameter changes by modulating the light intensity at different frequencies for different targets. The first target is associated with a first modulation frequency while the second target is associated with a second modulation frequency. The evaluation unit distinguishes between targets based on these frequency parameters, allowing the system to maintain continuous measurement capability while preventing misidentification of targets through frequency-based discrimination.
2Ease of operation
If the surveying instrument tracks a target based on light detection, then the instrument can automatically maintain orientation toward the target, but stray light or light from other objects may cause false tracking
Solution Approach 1:
The system uses parameter changes by assigning unique modulation frequencies to different targets. The evaluation unit processes light intensity signals and identifies targets based on their specific modulation frequencies. This frequency-based parameter discrimination enables automatic target tracking while filtering out stray light and light from unintended objects, thus maintaining measurement precision.
Solution Approach 2:
The modulation signal acts as an intermediary carrier that encodes target identification information. By modulating the light intensity at distinct frequencies for different targets, the system creates an intermediary signal layer that allows the detector and evaluation unit to distinguish between valid targets and false signals, enabling reliable automatic tracking without interference from stray light.
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 ensures robust tracking of the desired target by differentiating between light patterns, preventing false tracking of undesired targets and maintaining accurate orientation even when multiple targets are present within the field of view, enhancing measurement precision and reliability.
Implementation Method 1
receiving first light through a lens of the measuring unit and forming a first spot of the first light on the detector, wherein the first light is modulated light having an intensity which is modulated according to a first time pattern
Data Source
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AI summary
A surveying instrument performs tracking of a target by controlling an orientation of a measuring unit relative to the target in two different angular directions. The control in one angular direction is based on detected light intensities which are modulated according to a first time pattern, and control of the orientation in the other angular direction is based on detected light intensities modulated according to a second time pattern just different from the first time pattern.