LIDAR Spatial Resolution via Laser Frequency Modulation
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Solution Overview
Problem
Existing LIDAR measuring systems for determining wind speed face challenges in achieving precise spatial resolution without complex and costly components, and struggle to differentiate between positive and negative Doppler shifts, often requiring additional devices.
Innovation Solution
A LIDAR measuring device using a narrowband continuous wave laser light source with frequency modulation, allowing for adjustable spatial resolution and precise speed measurement of particles by varying the laser frequency and performing spectral analysis of the detector signal, eliminating the need for expensive components and additional devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If highly coherent laser light sources with sub-MHz bandwidth are used to achieve precise spatial resolution, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies parameter changes by modulating the laser frequency over time according to a known function, transforming the measurement approach from relying on high coherence to using frequency modulation. This allows spatial resolution to be determined by the modulation parameters rather than requiring sub-MHz bandwidth lasers, thereby reducing device complexity while maintaining measurement precision
Solution Approach 2:
The patent implements dynamics by using time-varying frequency modulation of the laser source instead of a static high-coherence approach. The frequency is dynamically changed according to a known function, enabling spatial resolution to be achieved through temporal variation rather than requiring highly coherent light sources, thus simplifying the device
2Measurement precision
If additional measuring devices are used to differentiate positive and negative Doppler shifts, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent applies feedback by using the known frequency modulation function as a reference signal in the evaluation process. The detected signal is compared against the expected modulation pattern, allowing the system to determine both the magnitude and sign of Doppler shifts through signal processing rather than additional hardware, thereby maintaining measurement precision without increasing device complexity
Solution Approach 2:
The patent replaces the mechanical approach of using additional physical measuring devices with a signal processing solution. By substituting hardware complexity with computational evaluation of the frequency-modulated signal, the system achieves Doppler shift differentiation through software/mathematical methods rather than additional mechanical components
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
Enables highly precise wind speed measurement with simple construction, allowing for independent selection of spatial and speed resolution, and reliable determination of particle movement direction without complex components, thus providing an economical and reliable solution for wind energy applications.
Implementation Method 1
narrowband continuous wave laser light source, which emits light modulated in its optical frequency
Implementation Method 2
the emitted light is at least partially scattered and/or reflected by the particles in the measuring volume
Implementation Method 3
the emitted light is at least partially scattered and/or reflected by the particles in the measuring volume
Implementation Method 4
at least one part of the scattered and/or reflected light is received by a receiver device
Implementation Method 5
The received light is then coherently superimposed with the light leaving the reference branch
Implementation Method 6
determine the speed of particles in a measuring volume... by taking into account the detector signal
Implementation Method 7
the resulting light beam is directed onto a detector to generate a detector signal characteristic for the resulting light beam
Data Source
AI summary
A LIDAR measuring device and a method for determining the speed of particles in a measuring volume includes a narrowband continuous wave laser light source (1), which emits light which is coupled into a measuring branch (3) and a reference branch (4). The light coupled into the measuring branch (3) is at least partially emitted by a transmitting device in the direction of the measuring volume such that the emitted light is at least partially scattered and/or reflected by the particles in the measuring volume. A part of the scattered and/or reflected light is then received by a receiver device and is coherently superimposed with the light leaving the reference branch (4), and the resulting light beam is directed onto a detector (6) to generate a detector signal characteristic for the resulting light beam. Finally, the speed of the particles in the measuring volume is determined in an evaluation unit (11) by taking into account the detector signal.