Coherent LiDAR Optical Path for Larger Aperture Echo Detection
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Solution Overview
Problem
Common laser radars face limitations due to the size of optical fibers, which restrict the energy of received echo signals, leading to low detection precision and accuracy.
Innovation Solution
Implementing a coherent detection optical path using beam shaping, beam splitting, and optical frequency mixing modules to increase the reception aperture and alleviate optical crosstalk, allowing for more energy to be received from echo signals, thereby improving precision through frequency mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an optical fiber path is used to transmit and receive signals, then the system structure is compact and easy to implement, but the reception aperture is limited by the optical fiber size, resulting in low echo signal energy and poor detection precision
Solution Approach 1:
The patent divides the optical path into separate transmitting and receiving paths, allowing the receiving aperture to be independently enlarged without being constrained by the optical fiber size. The transmitting optical path and receiving optical path are segmented to enable independent optimization of each function.
Solution Approach 2:
The patent transitions from a single optical path to a dual-path configuration, adding dimensional complexity to the system architecture. This allows the reception aperture to expand in spatial dimensions while the optical fiber remains constrained, resolving the aperture limitation.
2Reliability
If a single optical path is used for transmission and reception, then the system structure is simple, but optical crosstalk occurs between transmitted and received signals, reducing signal quality
Solution Approach 1:
The patent segments the optical path into distinct transmitting and receiving channels, physically separating the high-power transmitted signal from the weak received signal. This segmentation eliminates optical crosstalk while maintaining manageable system complexity through modular design.
Solution Approach 2:
The patent introduces separate optical paths as intermediary channels between the laser source and the target, and between the target and the detector. These intermediary paths prevent direct interaction between transmitted and received signals, eliminating crosstalk while preserving signal integrity.
3Use of energy by moving object
If the optical fiber size is increased to improve echo signal energy, then more signal energy can be received, but the optical fiber becomes larger and more difficult to implement
Solution Approach 1:
The patent separates the energy collection function from the signal transmission function. The large receiving aperture collects maximum signal energy, while the optical fiber's role is limited to transmitting the already-collected signal, allowing the fiber to remain small without compromising energy reception.
Solution Approach 2:
The patent extracts the energy collection function from the optical fiber and assigns it to a dedicated receiving optical path with a large aperture. The optical fiber retains only the signal transmission function, eliminating the need for large fiber dimensions while preserving signal energy.
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
Enhances the precision of detecting target objects by increasing the energy of received echo signals and improving frequency mixing efficiency, resulting in more accurate speed and distance measurements.
Implementation Method 1
a beam shaping module configured to perform collimation on the laser signal
Implementation Method 2
a beam splitting module configured to perform beam splitting on the laser signal obtained through collimation, to obtain a sounding signal and a local-frequency signal
Implementation Method 3
an optical frequency mixing module configured to perform frequency mixing on the echo signal and the local-frequency signal, to obtain a beat frequency signal
Implementation Method 4
a laser configured to generate a laser signal
Implementation Method 5
an echo signal formed by reflecting the laser signal by a target object
Data Source
Figure 1
Figure 2
Figure 2A
AI summary
A laser radar and an intelligent vehicle are provided, and may be specifically applied to the field of intelligent vehicles. The laser radar may include: a laser, configured to generate a laser signal; a beam shaping module, configured to perform collimation on the laser signal (step 300); a beam splitting module, configured to perform beam splitting on a laser signal to obtain a sounding signal and a local-frequency signal (step 301); a receiving module, configured to receive echo information and transmit the echo signal to an optical frequency mixing module (step 302); the optical frequency mixing module, configured to perform optical frequency mixing on the local-frequency signal and the echo information to obtain a first beat frequency signal and a second beat frequency signal (step 303); and a differential receiving unit, configured to differentially receive the first beat frequency signal and the second beat frequency signal, where the first beat frequency signal and the second beat frequency signal are used to determine at least one of a distance or a speed of a target object. The laser radar may transmit a signal through a space optical path, increase a reception aperture according to an actual requirement, and increase received echo signals.