Multi-Wavelength Doppler Lidar Adaptive Waveform Optimization
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Solution Overview
Problem
Current Doppler lidar systems face challenges in achieving high range and spatial resolution while maintaining measurement accuracy and speed, particularly in clear weather conditions, due to limitations in pulse power, pulse duration, and noise suppression, which complicates the detection of wind and turbulence for applications like airport safety and wind farm efficiency.
Innovation Solution
A multi-wavelength Doppler lidar system with individual pulse repetition frequencies, pulse shapes, and adaptive waveform optimization, allowing each channel to operate independently with unique ranges and sensitivities, enabling simultaneous optimization of range, spatial resolution, and velocity resolution, and automatic adjustment based on environmental conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the transmit pulse energy is increased to improve backscatter signal strength, then measurement range is extended, but laser power requirements increase and safety concerns arise
Solution Approach 1:
The patent divides the measurement task across multiple wavelength channels, each operating at lower power levels. By segmenting the single-channel approach into multi-channel operation, the system achieves extended effective range through combined signal detection while maintaining lower individual channel power levels, thus resolving the contradiction between range extension and power consumption
Solution Approach 2:
The patent combines signals from multiple wavelength channels to achieve the measurement objective. By merging the detection capabilities of several lower-power channels, the system attains the equivalent or superior performance of a single high-power channel, thereby extending measurement range without proportionally increasing laser power requirements
2Measurement precision
If pulse duration is increased to improve signal strength, then backscatter detection sensitivity increases, but spatial resolution deteriorates
Solution Approach 1:
The patent segments the measurement function across multiple wavelength channels, where different pulse durations can be optimized for different channels. This allows simultaneous achievement of high detection sensitivity (through longer pulses in some channels) and high spatial resolution (through shorter pulses in other channels), resolving the contradiction by distributing the optimization across segmented channels
Solution Approach 2:
The patent applies different pulse duration characteristics to different wavelength channels based on their specific detection requirements. Each channel can be locally optimized with appropriate pulse duration, allowing the system as a whole to achieve both high sensitivity and high spatial resolution through differentiated local characteristics across channels
3Measurement precision
If integration time is extended to improve signal-to-noise ratio, then measurement accuracy increases, but real-time capability is lost
Solution Approach 1:
The patent combines measurements from multiple wavelength channels to achieve improved signal-to-noise ratio within short integration times. By merging the information content of several channels simultaneously, the system attains high measurement accuracy without requiring extended integration periods, thus maintaining real-time measurement capability while improving precision
4Adaptability or versatility
If multiple wavelength channels are used to optimize different measurement parameters, then measurement versatility improves, but system complexity increases
Solution Approach 1:
The patent implements a multi-wavelength channel system where each channel can be independently configured for different measurement optimizations. This universal architecture allows the same hardware platform to perform multiple measurement functions by adjusting channel parameters, achieving high versatility while managing complexity through a unified multi-functional design rather than separate specialized systems
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 the sensitivity and range of Doppler lidar systems, allowing for accurate real-time measurement of wind velocities and turbulence, even at low backscatter intensities, and reduces operational complexity by optimizing waveform settings automatically or with external sensors.
Implementation Method 1
an electronic evaluation device (n×SV) for determining a Doppler shift amount between the transmitted light and the received light on N wavelength channels
Implementation Method 2
detecting a wind speed of the airflow in a remote area by scattering the laser light due to aerosol present in the atmosphere
Data Source
AI summary
Doppler lidar for detecting wind speeds, comprising a device (MO) for generating pulsed coherent laser light on N wavelength channels, amplitude modulation (AM) being performed separately for each individual wavelength channel for shaping the pulse individually for each channel, a device (TK, SC) for transmitting generated, frequency-shifted and amplified pulses of the laser light in predetermined spatial directions, a detector (n×Det.) for receiving the generated and the backscattered laser light on N wavelength channels, and an electronic evaluation device (n×SV) for determining a Doppler shift amount between the transmitted light and the received light on N wavelength channels, wherein a timing modulator (TM) is assigned to the N wavelength channels for individual control of a pulse repetition frequency (PRF) and/or pulse repetition period (PRT) in addition to the pulse shape for wavelength channels.