Time-Dependent Attenuation for Dynamic Range in Distance Measurement
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Solution Overview
Problem
Existing electronic distance measurement (EDM) systems face challenges in achieving faster scanning and adapting to a dynamic range of power levels in surveying instruments, as they rely on fixed attenuation functions that do not effectively compensate for the varying intensity of return pulses based on distance and geometrical parameters of the optical subsystem.
Innovation Solution
The implementation of a time-dependent attenuation function in EDM systems, where the attenuation is maximized at a critical time elapsed since the emission of the transmit light signal, dependent on geometrical parameters of the optical subsystem, allowing for increased sensitivity and reduced dynamic range by varying the attenuation level as time passes, thereby optimizing the power level of the return light signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed attenuation function is used, then the device complexity is reduced, but the adaptability to dynamic range of power levels deteriorates
Solution Approach 1:
The patent implements a time-dependent attenuation function where the attenuation value changes dynamically based on the time elapsed since pulse emission. This allows the system to adapt to varying power levels of return pulses from different distances, resolving the contradiction between device simplicity and dynamic range adaptability.
Solution Approach 2:
The attenuation function changes its parameter (attenuation value) based on time, creating a time-dependent relationship. This parameter change enables the system to handle the dynamic range of power levels without increasing overall device complexity, as the change is implemented through a functional relationship rather than additional hardware.
2Adaptability or versatility
If a time-dependent attenuation function is implemented, then the adaptability to dynamic range improves, but the device complexity increases
Solution Approach 1:
The system uses a time-dependent attenuation function that automatically adjusts attenuation values based on elapsed time since pulse emission. This dynamic approach improves adaptability to dynamic range while maintaining implementation simplicity through a single functional relationship rather than multiple fixed functions or complex hardware.
Solution Approach 2:
The time-dependent attenuation function serves itself by automatically determining the appropriate attenuation value based on the time parameter, eliminating the need for external control mechanisms or complex decision-making hardware. The function self-adjusts to provide optimal attenuation for the current measurement conditions.
3Measurement precision
If attenuation is maximized at critical time, then the measurement precision is improved, but the loss of time increases
Solution Approach 1:
The system pre-calculates and applies the appropriate attenuation value based on the expected time of return pulse arrival. By having the attenuation function ready and determined in advance based on time, the system achieves precise measurement without additional time loss during the measurement process itself.
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 enhances the accuracy and efficiency of distance measurements by maximizing the return light signal at a specific distance, reducing the influence of optics-dependent variations and allowing for improved compensation, leading to faster scanning and better dynamic range adaptation in surveying instruments.
Implementation Method 1
an opto-electrical converter to convert the return light signal to a return electrical signal
Data Source
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AI summary
A transmit light signal is emitted toward a target at an emission time. An optical subsystem of a receiving system receives a return light signal which is converted to a return electrical signal. At least one attenuator applies an attenuation to at least one of the return light signal and the return electrical signal. The attenuation varies, as time passes, after emission of the transmit light signal, according to a time -dependent attenuation function such that the attenuation is maximum at a critical time elapsed since an emission time of the transmit light signal. The critical time is dependent on at least one geometrical parameter of the optical subsystem. A receive time is determined from the return electrical signal. The emission time and the receive time are used to calculate a measured distance.