FMCW LiDAR Threshold Modulation for Long-Range Signal Detection
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Solution Overview
Problem
FMCW LiDAR systems struggle to accurately detect distant objects due to significant amplitude loss in scattered beams, affecting the comprehensive representation of vehicle surroundings and overall safety.
Innovation Solution
The system modulates the amplitude of the FMCW signal based on a predetermined threshold ranging distance, amplifying the reflected signal as a function of distance to enhance detection of distant objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If FMCW LiDAR systems use standard detection methods, then the system structure remains simple, but the detection capability for distant objects deteriorates due to significant amplitude loss in scattered beams
Solution Approach 1:
The patent applies preliminary action by modulating the amplitude of the FMCW signal before transmission based on a predetermined threshold ranging distance. This pre-modulation prepares the signal to compensate for expected amplitude loss during propagation, enabling distant objects to be detected with sufficient signal strength without requiring complex post-detection amplification systems.
Solution Approach 2:
The patent changes the amplitude parameter of the FMCW signal dynamically based on the ranging distance. By adjusting the amplitude modulation depth according to the threshold distance, the system optimizes the transmitted signal characteristics to match the expected path loss, thereby improving detection capability for distant objects while maintaining system simplicity.
2Length of stationary object
If the LiDAR system increases transmission power to detect distant objects, then detection range improves, but energy consumption and potential harmful effects increase
Solution Approach 1:
Instead of uniformly increasing transmission power, the patent changes the amplitude parameter selectively based on the threshold ranging distance. The amplitude modulation is adjusted only for signals destined for distant detection, allowing the system to extend detection range for specific targets without proportionally increasing overall energy consumption and harmful effects.
Solution Approach 2:
The patent applies partial action by modulating the amplitude of only the necessary portion of the FMCW signal based on the threshold distance. Rather than continuously maximizing transmission power across all operations, the system applies amplitude modulation only when and where needed for distant object detection, reducing unnecessary energy consumption and harmful effects.
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 a more comprehensive and accurate 3D representation of the vehicle's surroundings, improving detection range and safety by registering more distant objects.
Implementation Method 1
a frequency modulator configured to modulate a frequency of the continuous wave, thereby producing a Frequency-Modulated-Continuous-Wave (FMCW) signal
Implementation Method 2
Frequency modulated continuous wave (FMCW) light sources
Implementation Method 3
by superimposing the scattered FMCW signal with the initial one (i.e., the one that initially has been produced by the local oscillator), based on a Doppler effect, a current velocity of the surrounding object relative to the LiDAR system may be yielded
Data Source
AI summary
A LiDAR system and a method for operation thereof are provided. The LiDAR system comprises: a frequency-modulated continuous wave (FMCW) light source configured to produce an FMCW signal; and an amplitude modulator configured to modulate an amplitude of at least a portion of the FMCW signal, thereby producing an Amplitude-Frequency-Modulated-Continuous-Wave (AFMCW) signal; a splitter configured to split one of the FMCW signal and the AFMCW signal into a first portion and a second portion, the first portion being an output signal for reflecting off the object, thereby producing a reflected signal, and the second portion being a reference signal for amplifying the reflected signal; and a detector configured to amplify the reflected signal based on the reference signal as a function of a distance from the LiDAR system to an object, thereby generating an amplified reflected signal for determining the distance to the object.