Distance Meter Sampling Control for Low-Aliasing Precision Ranging
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Solution Overview
Problem
Existing distance measurement methods face challenges with signal sampling and reconstruction, particularly when dealing with variable or distorted signals, leading to aliasing effects that reduce measurement accuracy and require complex filtering or high-frequency components, limiting precision and equipment simplicity.
Innovation Solution
Adapting the sampling rate based on a rough distance estimate, allowing for optimal sampling frequency selection to reduce aliasing effects and enable accurate measurements without extensive filtering, even with non-linearly distorted pulses, by sampling signals at identical points relative to the signal curve, and using a start signal for reference to eliminate errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-frequency sampling is used to avoid aliasing effects, then measurement accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies dynamic sampling by adjusting the sampling frequency based on the rough distance estimate. The sampling frequency is dynamically adapted to match the signal characteristics at different distances, allowing accurate measurement without consistently using the highest possible sampling rates, thus reducing device complexity while maintaining precision.
Solution Approach 2:
The patent changes the sampling parameter (sampling frequency) based on the measured distance. By modifying the sampling frequency to match the expected signal bandwidth at different distances, the system achieves accurate measurements without requiring uniformly high sampling rates across all measurement ranges, simplifying the overall device requirements.
2Measurement precision
If sophisticated filtering is applied before sampling to comply with Nyquist theorem, then aliasing effects are reduced, but device complexity increases
Solution Approach 1:
The patent performs a preliminary rough distance measurement before the actual precise measurement. This preliminary action provides information about the expected signal characteristics, allowing the system to configure appropriate sampling parameters in advance, thereby avoiding the need for complex real-time filtering while maintaining measurement accuracy.
Solution Approach 2:
The system uses feedback from the rough distance measurement to adjust the sampling frequency for the subsequent precise measurement. This feedback mechanism allows the system to adapt its sampling strategy based on actual measurement conditions, eliminating the need for overly complex pre-filtering circuits.
3Device complexity
If the sampling rate is fixed, then device simplicity is maintained, but measurement accuracy decreases due to aliasing effects
Solution Approach 1:
The patent transitions from fixed sampling to dynamic sampling where the sampling frequency is adjusted based on the rough distance estimate. This dynamic adaptation allows the system to maintain simplicity in the basic circuit design while achieving high measurement accuracy through intelligent parameter selection.
4Measurement precision
If high-order filters are used to reduce aliasing, then measurement accuracy is improved, but device complexity and processing effort increase
Solution Approach 1:
The patent changes the sampling frequency parameter based on distance estimates, which effectively controls the signal bandwidth without requiring high-order filters. By adapting the sampling rate to match the expected signal characteristics, the system achieves equivalent filtering效果 with simpler circuits.
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 high-precision distance measurements in the mm or sub-mm range with reduced filtering effort, allowing for accurate measurements even with slower analog-to-digital converters and higher-frequency components, while simplifying the measurement process.
Implementation Method 1
emit pulsed electromagnetic radiation, such as laser light, onto a target to be measured and then to receive an echo from this target as a backscattering object
Implementation Method 2
the distance to the target to be measured being determined using the transit time of the pulse
Data Source
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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 (S) is produced, and the measurement signal is back scattered from the target object as a target signal (Z). Said target signal (Z) is sampled at a sampling frequency and the relative position of the start signal (S) and the target signal (Z) is determined for deriving a distance to the target object from the relative position from the start signal (S) and the target signal (Z). The sampling frequency can be adjusted and is set in accordance with a large distance to the target object.