FMCW Laser Ranging Frequency Comparison
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Solution Overview
Problem
The existing laser ranging methods face accuracy issues due to random time interval measurements and complex internal structures, leading to increased manufacturing costs and hindered miniaturization.
Innovation Solution
A ranging method and system that modulates the laser beam with a continuously changing frequency signal, allowing for precise distance calculation by comparing the frequency of the emitted and received signals, simplifying the system and reducing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If direct counting method of digital clock is used to calculate time interval, then ranging method is simple, but ranging accuracy is poor due to random time interval and clock cycle errors
Solution Approach 1:
The patent changes the measurement parameter from direct time interval counting to frequency comparison. By measuring the frequency difference of modulated signals instead of counting clock cycles over random time intervals, the system achieves higher precision while maintaining simplicity. The frequency comparison method eliminates random error accumulation inherent in time interval counting.
2Measurement precision
If phase measurement method is used to improve accuracy, then ranging precision is improved, but internal structure and control method become complicated, increasing manufacturing cost and hindering miniaturization
Solution Approach 1:
The patent extracts and eliminates the need for an internal optical path reference signal that is required by traditional phase measurement methods. By using frequency comparison of modulated signals, the system achieves high precision ranging without requiring complex internal reference paths, thereby simplifying the device structure and enabling miniaturization.
Solution Approach 2:
The patent replaces the complex optical-mechanical phase measurement system with a simpler electronic frequency comparison system. Instead of using interferometric methods requiring precise optical path control, the invention uses electronic signal modulation and frequency analysis, which are easier to implement and miniaturize while achieving comparable or superior precision.
3Measurement precision
If phase measurement with internal reference signal is used, then ranging precision is improved, but manufacturing cost increases due to complicated structure
Solution Approach 1:
The patent removes the requirement for internal optical reference signals and complex interferometric setups. By using frequency-modulated continuous wave (FMCW) ranging with frequency comparison, the system achieves high precision with a simplified structure that is easier and less expensive to manufacture.
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 results in a simple, pragmatic, and precise ranging system with improved accuracy and reduced manufacturing costs, facilitating miniaturization and wider application.
Implementation Method 1
modulating measured beam, by a modulated signal of which the frequency is continuously changed over time
Implementation Method 2
comparing the frequency of the modulated signal generated when the measured beam is received with the frequency of the measured signals
Data Source
AI summary
The invention relates to the topographic technique field, and provides a ranging method and a system, wherein the ranging method comprises the following steps: modulating measured beam, by a modulated signal of which the frequency is continuously changed over time; emitting the modulated measured beam to a measured object; receiving the reflected measured beam and converting the beam into the measured signals; and comparing the frequency of the modulated signal generated when the measured beam is received with the frequency of the measured signals, thus determining the measured distance.