Lidar Spectrum Analyzer Stabilizes Scattered Radiation
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Solution Overview
Problem
Conventional pulsed lasers used in Lidar systems have unpredictable variations in laser pulse characteristics, making it difficult to achieve precise measurements of scattered radiation spectra, especially outside laboratory settings due to factors like vibrations affecting the optical path length and wavelength.
Innovation Solution
Determining the frequency of laser pulses as a characteristic, using a spectrum analyzer to stabilize and store this data with measurement data from a radiation sensor, allowing for accurate reconstruction of scattered radiation spectra even with unstable laser pulses, and implementing a quality criterion to filter out unsuitable pulses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional pulsed lasers are used outside the laboratory, then the device can be deployed in challenging environments (ship, satellite), but the laser pulse characteristics vary profoundly from pulse to pulse due to vibrations and sound
Solution Approach 1:
The patent implements feedback by measuring the actual frequency of each laser pulse with a spectrum analyzer and using this measured frequency as a reference for evaluating scattered radiation spectra. The system continuously monitors laser pulse characteristics and adjusts the evaluation process accordingly, creating a closed-loop system that compensates for vibrations and environmental disturbances without requiring mechanical stabilization.
Solution Approach 2:
The patent changes the approach from attempting to maintain constant laser parameters to accepting parameter variations and using the actual measured parameters (frequency, wavelength) as dynamic references. By shifting from a static reference framework to a dynamic one based on actual pulse characteristics, the system can accurately evaluate scattered radiation despite environmental disturbances.
2Measurement precision
If the characteristics of laser pulses are stabilized in the laboratory, then measurement precision improves, but the complexity of controlling the pulsed laser increases
Solution Approach 1:
The patent introduces a spectrum analyzer as an intermediary device that measures the actual frequency and wavelength of each laser pulse. This intermediary provides accurate reference data without requiring complex mechanical stabilization systems, thereby maintaining measurement precision while avoiding the complexity of active laser control mechanisms.
Solution Approach 2:
The patent replaces mechanical stabilization systems (which would be complex and difficult to implement in mobile platforms) with an optical measurement approach using a spectrum analyzer. Instead of mechanically controlling laser pulse stability, the system optically measures and records the actual characteristics, substituting a complex mechanical control problem with a simpler measurement and data processing approach.
3Measurement precision
If many laser pulses are measured to improve spectrum determination accuracy, then the measurement time increases, but the productivity decreases
Solution Approach 1:
The patent performs preliminary measurement of laser pulse characteristics (frequency, wavelength) before using them for scattered radiation evaluation. By having the reference data ready and associated with each pulse beforehand, the system can quickly evaluate spectra without requiring extensive post-processing or repeated measurements, thereby maintaining accuracy while improving efficiency.
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 method enables more accurate determination of scattered radiation spectra, allowing for precise measurements of gas properties such as temperature and wind speed, with improved accuracy and stability, even in challenging environments like on ships or satellites.
Implementation Method 1
with a pulsed laser (2), whose laser pulses (P) that are emitted during the operation of the device are scattered
Implementation Method 2
laser pulses (P) that are emitted during the operation of the device are scattered so as to generate the scattered radiation
Data Source
AI summary
The invention relates to a device (1) and a method (20) for determining a spectrum (X) of scattered radiation (S). The invention further relates to a method (70) for calculating the spectrum (X) and a method for compressing unstructured data (60) of known distribution. To be able to determine the spectrum (X) as precisely as possible and to derive from this the characteristics of materials that scatter laser pulses (P), the invention proposes that at least one characteristic of the laser pulse (P) is determined and that a spectrum analyzer (5) is used for this. Frequencies (F) of laser pulses (P) and volumes (M) of backscattered radiation (S) are combined into frequency and volume values (F′, M′) to calculate the spectrum (X). The most frequent data values are deleted from the data to compress the data (60).