Laser Radar Line of Sight Determination via Frequency Shift
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Solution Overview
Problem
Current techniques fail to determine the line of sight in laser radar devices when communication errors or synchronization errors occur during switching between lines of sight, making it difficult to correlate measurement data with the correct lines of sight.
Innovation Solution
A laser radar device applies different frequency shifts to pulsed transmission light corresponding to each line of sight, allowing for the assignment and identification of these shifts, thereby enabling the determination of the line of sight from measurement data and improving the reliability of wind measurement lidar systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If synchronization is performed between line-of-sight switching signal and measurement data, then line of sight can be determined from measurement data, but the system becomes vulnerable to communication errors and synchronization errors
Solution Approach 1:
The patent introduces frequency shift as an intermediary identifier that mediates between the line of sight switching and measurement data. Each line of sight is assigned a unique frequency shift, which acts as a marker that can be detected in the measurement data without requiring complex synchronization protocols or communication channels between the switching control and data acquisition systems.
Solution Approach 2:
The patent changes the frequency parameter of the transmitted light according to the line of sight being measured. By applying different frequency shifts to different lines of sight, the system encodes line of sight information directly into the physical parameter of the light signal, making it easily identifiable in the received measurement data without requiring additional synchronization mechanisms.
2Measurement precision
If different frequency shifts are applied to different lines of sight, then measurement data can be accurately associated with lines of sight, but the signal processing complexity increases
Solution Approach 1:
The patent utilizes frequency shift as a distinguishable parameter to identify different lines of sight. By applying different frequency shifts to different lines of sight, the system creates unique spectral signatures for each line of sight, which can be easily separated and identified using standard frequency analysis techniques, thereby achieving precise line of sight identification without overly complex processing.
Solution Approach 2:
The patent transforms the line of sight identification problem from a temporal-synchronization domain into a frequency-domain problem. Instead of tracking when a line of sight is selected, the system encodes line of sight information in the frequency characteristic of the signal, allowing for more robust and simpler identification through frequency spectrum analysis.
3Reliability
If synchronization detection is implemented, then line of sight switching can be tracked, but communication errors cause loss of line of sight information
Solution Approach 1:
The frequency shift serves as a self-contained intermediary that carries line of sight identification information within the measurement signal itself. This eliminates the need for separate synchronization communication channels, so communication errors in external control signals do not cause loss of line of sight information. The frequency-encoded identifier remains intact and detectable even if other control communications fail.
Solution Approach 2:
The system implements a form of feedback where the transmitted signal itself contains the identification information needed to verify which line of sight is being measured. The frequency shift applied to each line of sight creates a detectable signature in the returned signal, providing inherent feedback that confirms line of sight identification without relying on external synchronization commands that could be corrupted by communication errors.
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 allows for accurate determination of the line of sight from measurement data, enhancing the reliability of wind measurement lidar systems and simplifying the system by eliminating the need for synchronization between line-of-sight switching signals and measurement signals.
Implementation Method 1
an optical phase modulator configured to apply different frequency shifts to pulsed transmission light according to lines of sight
Data Source
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AI summary
There is the problem with conventional laser radar devices that it is difficult to determine the line of sight from measurement data. A laser radar device according to the present invention includes: a wavelength-tunable light source configured to emit light with a plurality of wavelengths; an optical branch coupler configured to divide the light emitted by the wavelength-tunable light source into local light and transmission light; an optical phase modulator configured to apply, to the transmission light or the local light, frequency shifts for wavelength discrimination of different shift amounts corresponding to the respective wavelengths of the light emitted by the wavelength-tunable light source; a wavelength separator configured to perform switching between light paths for output, in response to a wavelength of the transmission light; an optical antenna configured to emit into space the transmission light output by the wavelength separator, and configured to receive, as received light, backward-scattered light generated from transmission light in space in which lines of sight corresponding to the respective wavelengths of the transmission light are determined; an optical heterodyne receiver configured to receive the local light and the received light, and configured to perform heterodyne detection; and a signal processor configured to perform frequency analysis of an output signal of the optical heterodyne receiver.