Phase-Modulated Distance Sensor Signal Correlation
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Solution Overview
Problem
Traditional distance measurement apparatuses face limitations in scanning speed and image spatial resolution due to mechanical scanning, and suffer from weak echo signal energy and interference issues, which affect accuracy and reliability.
Innovation Solution
A distance measurement method that adjusts the initial phase and/or pulse width of the demodulation signal until an overlapping portion exists between the demodulation signal and the echo radiation, improving signal-to-noise ratio and reducing interference by correlating echo radiation with sub-demodulation signals to determine the distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the photosensitive surface area of the receiving end is increased or the integration time is extended to solve weak echo signal energy, then the signal-to-noise ratio is improved, but the accuracy of measured distance is reduced
Solution Approach 1:
The patent changes the temporal parameters of the demodulation signal (initial phase and pulse width) to optimize the correlation between the demodulation signal and echo radiation. By adjusting these parameters dynamically, the system achieves high signal-to-noise ratio without requiring increased photosensitive area or extended integration time, thereby maintaining measurement accuracy.
2Device complexity
If traditional mechanical scanning is used for distance measurement, then the apparatus structure is simple, but the scanning speed is slow and image spatial resolution is low
Solution Approach 1:
The patent replaces the mechanical scanning system with an optical field-based demodulation approach. Instead of using mechanical scanners to sweep through different spatial positions, the system uses phase-modulated optical signals and correlation demodulation to achieve spatial resolution and fast scanning without moving parts, thereby dramatically increasing scanning speed while maintaining structural simplicity.
3Area of stationary object
If multiple distance measurement apparatus are used to improve measurement coverage, then the measurement range is increased, but mutual interference between apparatus increases
Solution Approach 1:
The patent segments the measurement space by assigning different initial phases to different distance measurement apparatus. This phase segmentation allows multiple apparatus to operate simultaneously without mutual interference, as each apparatus operates in a distinct phase domain. The correlation demodulation process can then separately identify and process signals from different apparatus based on their unique phase signatures.
4Measurement precision
If the pulse width of the demodulation signal is reduced to improve distance measurement precision, then the measurement accuracy is improved, but the signal energy is reduced
Solution Approach 1:
The patent employs continuous correlation demodulation processing that accumulates signal energy over time through coherent integration. By maintaining continuous correlation between the demodulation signal and echo radiation, the system achieves high measurement precision with narrow pulse widths while recovering signal energy through temporal integration, effectively decoupling precision from signal energy requirements.
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
Enhances the signal-to-noise ratio, improves accuracy, and reduces mutual interference between distance measurement apparatuses, enabling higher precision and range in distance measurement.
Implementation Method 1
the radiation is modulated on a transmitting end by using a modulating signal
Implementation Method 2
the echo radiation comes from the reflection of the radiation on an object to be measured
Implementation Method 3
correlating the echo radiation with the at least two sub-demodulation signals to obtain a correlation value; determining the phase relationship according to the correlation value
Data Source
AI summary
A distance measurement method, a distance measurement sensor, and a distance measurement sensing array, for use in improving the signal-to-noise ratio of a distance measurement system and increasing the distance measurement accuracy and a distance measurement distance. The method comprises: a receiving end obtains echo radiation, the echo radiation being from a reflecting action performed by an object to be measured on radiation, and the radiation being obtained by a transmitting end by modulating a modulating signal (S202) the receiving end performs at least one adjustment on the initial phase and/or pulse width of a demodulation signal or demodulating the echo radiation until the demodulation signal satisfies a preset condition, the preset condition comprising that an overlapping portion exists between the phase of the demodulation signal and the phase of the echo radiation (S203); the receiving end determines a distance between the transmitting end and the object to be measured according to the overlapping portion and the current phase of the demodulation signal (S204).