FMCW LiDAR Sweep Profile for Short-Range High-Speed Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current FMCW lidar systems face demodulation errors and are unable to accurately measure high-speed objects in short range, and suffer from multiple echo issues due to triangular wave frequency sweep.
Innovation Solution
Implementing a frequency modulated continuous wave (FMCW) detection method with a three-stage frequency sweep waveform consisting of a rising edge, horizontal region, and falling edge, and using amplitude thresholds and echo matching techniques to calculate distance and speed components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If triangular wave frequency sweep is used to obtain time delay and Doppler frequency shift simultaneously, then both parameters can be measured, but demodulation errors occur and high-speed objects in short range cannot be accurately measured
Solution Approach 1:
The patent divides the frequency sweep waveform into three distinct sections: rising edge, horizontal region, and falling edge. Each section serves a specific function in the measurement process, allowing separate analysis of distance and velocity components without interference, thereby eliminating demodulation errors for high-speed objects
Solution Approach 2:
The patent assigns different functional qualities to different parts of the frequency sweep waveform. The rising and falling edges are optimized for distance measurement, while the horizontal region is optimized for velocity measurement through Doppler frequency shift analysis, enabling accurate simultaneous measurement of both parameters
2Loss of information
If triangular wave frequency sweep is used, then distance and speed information can be obtained, but multiple echo issues occur due to mismatched echoes in rising and falling edges
Solution Approach 1:
The patent performs preliminary echo matching by establishing correspondence between echoes in the rising edge and falling edge before final signal processing. This preliminary organization of echo data simplifies subsequent processing and eliminates the complexity of matching mismatched echoes
Solution Approach 2:
The horizontal region acts as an intermediary element that provides a reference for matching echoes from the rising and falling edges. By using the horizontal region's frequency characteristics as a mediator, the system can accurately pair corresponding echoes without complex matching algorithms
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
Resolves demodulation errors and multiple echo problems, enabling accurate measurement of high-speed objects in short range by distinguishing and matching echoes effectively.
Implementation Method 1
In order to obtain the time delay and a Doppler frequency shift of the echo signal at the same time
Implementation Method 2
an actual effective beating time period is the difference between a current linear frequency modulation duration and the echo delay time
Data Source
Figure 1~2
Figure 3A~4
Figure 5~6B
AI summary
Provided in the present disclosure is a method of performing detection using a frequency modulated continuous wave (FMCW). The method includes: S11: transmitting a detection wave according to a preset frequency sweep waveform to detect a target object; S12: receiving an echo of the detection wave reflected from the target object; and S13: obtaining a distance to and/or a speed of the target object according to the echo and the detection wave, wherein one cycle of the preset frequency sweep waveform consists of a rising edge, a horizontal region, and a falling edge.