Distance Measurement Sampling Rate Adaptation to Reduce Aliasing
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Solution Overview
Problem
Existing distance measurement technologies face challenges with aliasing effects and reduced measurement accuracy due to limitations in sampling rates and filter orders, particularly when dealing with variable or distorted signals, which restrict the use of higher-frequency components and require complex filtering to comply with the Nyquist theorem.
Innovation Solution
Adapting the sampling rate based on a coarse distance estimate allows for accurate sampling of signal profiles, reducing aliasing effects by aligning sampling points with signal peaks, and using a start signal for comparison to eliminate errors, enabling precise distance measurement without extensive filtering, even with nonlinearly distorted pulses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sampling rate is increased to capture higher-frequency signal components, then measurement accuracy is improved, but the device complexity and cost increase due to requiring faster analog-to-digital converters
Solution Approach 1:
The patent performs a preliminary coarse distance measurement using a simpler threshold value method before the fine sampling-based measurement. This preliminary action provides the necessary distance information to configure an appropriate sampling rate for the subsequent precise measurement, avoiding the need for always using the highest possible sampling rates and thus reducing the requirements for the analog-to-digital converter
Solution Approach 2:
The patent dynamically adjusts the sampling rate parameter based on the coarse distance measurement results. By changing the sampling rate to match the actual measurement needs rather than using a fixed high rate, the system achieves high measurement accuracy while reducing the performance requirements and complexity of the analog-to-digital converter
2Measurement precision
If higher-order filters are used to suppress aliasing effects and comply with the Nyquist theorem, then measurement accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent performs a preliminary coarse distance measurement using a simpler threshold value method before the fine sampling-based measurement. This preliminary action provides the necessary distance information to configure an appropriate sampling rate for the subsequent precise measurement, avoiding the need for always using the highest possible sampling rates and thus reducing the requirements for the analog-to-digital converter
Solution Approach 2:
The patent dynamically adjusts the sampling rate parameter based on the coarse distance measurement results. By changing the sampling rate to match the actual measurement needs rather than using a fixed high rate, the system achieves high measurement accuracy while reducing the performance requirements and complexity of the analog-to-digital converter
3Device complexity
If the sampling rate is kept low to simplify the device, then device complexity is reduced, but aliasing effects occur and measurement accuracy deteriorates
Solution Approach 1:
The patent makes the sampling rate dynamic rather than fixed. The sampling rate is adapted based on the measured distance and signal characteristics, allowing the system to use lower sampling rates when appropriate (reducing complexity) while maintaining high accuracy when needed. This dynamic adjustment resolves the contradiction between low complexity and high precision
Solution Approach 2:
The patent dynamically adjusts the sampling rate parameter based on the coarse distance measurement results. By changing the sampling rate to match the actual measurement needs rather than using a fixed high rate, the system achieves high measurement accuracy while reducing the performance requirements and complexity of the analog-to-digital converter
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 enables highly accurate distance measurements in the mm or sub-mm range, allowing the use of higher-frequency components and simplifying the construction of distance measuring elements, particularly with slower analog-to-digital converters, while minimizing equipment outlay and aliasing errors.
Implementation Method 1
the distance to the target to be measured is determined on the basis of the time of flight of the pulse
Implementation Method 2
If the so-called Nyquist sampling theorem is not complied with, then so-called aliasing effects can occur, which corrupt the signal reconstruction and thus reduce the measurement accuracy
Data Source
AI summary
The invention relates to a distance measuring method comprising at least the step of emitting at least one measurement signal to a target object, in which at least one start signal is produced, and the measurement signal is back scattered from the target object as a target signal. Said target signal is sampled at a sampling frequency and the relative position of the start signal and the target signal is determined for deriving a distance to the target object from the relative position from the start signal and the target signal. The sampling frequency can be adjusted and is set in accordance with a large distance to the target object.