Laser Radar Angle Compensation via Digital Signal Selection
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Solution Overview
Problem
Conventional laser radar devices face challenges in compensating for angle differences between transmission and received light due to low responsivity and mechanical limitations, leading to decreased signal intensity and signal-to-noise ratio (SNR).
Innovation Solution
A laser radar device with a light source array emitting multiple laser beams, an optical splitter, an optical modulator, a transmission/reception optical system, an optical combiner, an optical receiver array, a switching circuit, and a signal processor that selects detection signals based on scanning speed to compensate for angle differences without mechanical optical compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an optical axis correcting unit with two wedge prisms is used to compensate for angle difference, then the received signal intensity is maintained, but the responsivity is low and the response time is too slow (several tens of nsec) to compensate for angle differences occurring at optical propagation times of approximately 0.66 μsec
Solution Approach 1:
The patent replaces the mechanical wedge prism rotation system with a digital signal processing approach. Instead of mechanically adjusting optical components to compensate for angle differences, the system uses multiple optical receivers positioned at different angles and digitally selects or combines their signals based on the calculated angle difference, achieving compensation without mechanical movement and with much faster response time.
Solution Approach 2:
The patent divides the single angle difference compensation function into multiple parallel optical receivers, each positioned to receive light at a specific angle. By segmenting the reception function across multiple fixed receivers, the system eliminates the need for mechanical adjustment while maintaining the ability to compensate for angle differences through digital signal selection or combination.
2Reliability
If mechanical rotation of wedge prisms is used for angle difference compensation, then the system structure is complex, but the response time cannot meet the requirement of several tens of nsec
Solution Approach 1:
The patent eliminates the mechanical rotation mechanism by using multiple fixed optical receivers with different fields of view. The angle difference compensation is achieved through digital signal processing that selects or combines signals from appropriate receivers, thereby maintaining reliability while significantly reducing mechanical complexity.
3Measurement precision
If low machining accuracy or assembly accuracy is present in wedge prisms and optical components, then the angle difference cannot be correctly compensated for, causing received signal intensity to decrease and SNR to degrade
Solution Approach 1:
The patent replaces precision mechanical optical alignment with digital signal processing. By using multiple optical receivers with known, fixed angular positions and selecting or combining their signals based on calculated angle differences, the system achieves high compensation precision without relying on the manufacturing and assembly precision of complex optical components like wedge prisms.
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 configuration allows for high-SNR detection signals to be selected, enabling accurate calculation of target state observations even with angle differences, and achieves high responsivity without the need for structural optical compensation.
Implementation Method 1
an optical combiner configured to generate a plurality of interference light components by combining the received light and the plurality of local light components
Implementation Method 2
an optical receiver array including a plurality of optical receivers arranged at respective positions that optically correspond to different receiving fields of view of the transmission/reception optical system, and configured to generate a plurality of detection signals by detecting the plurality of interference light components
Data Source
AI summary
A laser radar device (1) includes: a light source array (10) for simultaneously emitting a plurality of laser light beams from a plurality of light emitting ends; an optical modulator (12) for modulating transmission light separated from the plurality of laser light beams to generate modulated transmission light; a transmission/reception optical system (14, 15) for receiving, as received light, the modulated transmission light reflected by a target, while scanning external space with the modulated transmission light; an optical combiner (16) for generating a plurality of interference light components by combining a plurality of local light components separated from the plurality of laser light beams and the received light; an optical receiver array (17) for generating a plurality of detection signals by detecting the plurality of interference light components; a switching circuit (18) for selecting a detection signal from the plurality of detection signals in accordance with a scanning speed with respect to the external space; and a signal processor (20) for calculating an observation quantity showing a state of the target on the basis of the selected detection signal.