Doppler Velocimeter Signal Processing Error Correction
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Solution Overview
Problem
Existing Doppler velocimeters face challenges in measurement accuracy due to low signal-to-noise ratio and noise interference, which can lead to errors in velocity measurement, especially when only level or period errors are present without dropout generation.
Innovation Solution
The velocimeter employs a processor that filters and binarizes signals using a band-pass filter, calculates velocity based on clocked rising intervals, and determines errors by comparing index changes to a threshold, allowing for accurate measurement even with noise and dropout conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a band pass filter is used to remove noise from the Doppler signal, then the signal-to-noise ratio is improved, but measurement accuracy decreases when only level or period errors are present without dropout
Solution Approach 1:
The invention dynamically adjusts the error determination criteria based on signal characteristics. Instead of using a fixed threshold, the system adapts the determination of level errors and period errors by analyzing the actual signal behavior, allowing accurate error detection even when dropout is not generated. This dynamic approach resolves the contradiction by making the measurement system responsive to varying signal conditions while maintaining noise rejection.
Solution Approach 2:
The invention changes the parameter used for error determination from fixed threshold-based methods to variable criteria that consider the relationship between level errors and period errors. By modifying how errors are identified and weighted, the system maintains measurement accuracy across different signal conditions while preserving the noise filtering benefits of the band pass filter.
2Reliability
If error determination requires both level error and period error to be generated, then false errors are reduced, but errors are missed when only one type of error is generated
Solution Approach 1:
The invention implements dynamic error determination that adapts to the specific signal conditions. When dropout is detected, the system uses one error determination criterion; when dropout is not detected but level or period errors are present, it uses alternative criteria to identify errors. This dynamic adaptation ensures that errors are correctly identified regardless of which specific error type occurs, resolving the contradiction between reducing false errors and avoiding missed errors.
3Device complexity
If the velocimeter uses traditional error detection methods, then the device complexity is low, but measurement accuracy decreases due to noise mixing
Solution Approach 1:
The invention introduces feedback mechanisms where the system continuously monitors signal characteristics and adjusts error determination criteria accordingly. By using the output of one processing stage to inform subsequent stages, the system achieves high measurement accuracy without requiring complex additional hardware. The feedback loop allows the velocimeter to learn from signal patterns and adapt its error detection sensitivity, resolving the contradiction between simplicity and accuracy.
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 measurement precision and robustness against noise and dropout, providing accurate velocity measurements by correcting for errors and improving signal processing techniques.
Implementation Method 1
a velocimeter that detects light modulated by a moving object with the Doppler effect and measures the velocity of the object
Data Source
Figure 1
Figure 2A~2C
Figure 3~4
AI summary
A velocimeter configured to detect light modulated by a moving object with a Doppler effect and measure a velocity of the object includes a detector (100) for detecting the light and obtaining a signal based on the detected light, and a processor (101) for performing binarization of the signal obtained by the detector, and measuring a time duration over a predetermined number of pulse intervals in the signal obtained by the binarization to obtain a measurement value of the velocity. The processor is configured to determine the measurement value as an error based on a change in an index relating to the time duration.