FMCW LiDAR Active Modulation for Simultaneous Range and Velocity
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Solution Overview
Problem
Frequency-modulated continuous-wave (FMCW) LIDAR systems face limitations in quickly and efficiently obtaining target information, such as velocity and range, due to the need to wait for signals to be transmitted and received, and can alias short-range targets, leading to disambiguation issues.
Innovation Solution
The implementation of a LIDAR system that applies amplitude modulation (AM) or time of flight (TOF) signaling to frequency-modulated (FM) signals, enabling simultaneous range and velocity measurement by processing reflection signals with active or passive modulation, and using combined FM and AM signals to extract range and Doppler information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If FMCW LIDAR systems use upchirp and downchirp signals to capture target information, then velocity and range information can be obtained, but the system cannot quickly and efficiently obtain target information due to waiting for signal transmission and reception
Solution Approach 1:
The patent applies periodic amplitude modulation to the FMCW signal, creating distinct modulation cycles that allow for faster processing. By modulating the signal amplitude periodically and processing multiple modulation cycles within a single chirp period, the system can extract target information more rapidly without waiting for complete signal round trips, thus improving productivity while reducing time loss.
2Measurement precision
If FMCW LIDAR systems use upchirp and downchirp signals to measure range and velocity, then target information can be captured, but short-range targets are aliased leading to disambiguation issues
Solution Approach 1:
The patent segments the measurement process by applying amplitude modulation that creates distinct signal components for different range-velocity combinations. The modulation divides the continuous FMCW signal into discrete measurable segments, allowing the system to differentiate between short-range and long-range targets that would otherwise be aliased, thus improving both measurement precision and reliability.
Solution Approach 2:
The amplitude modulation acts as an intermediary that adds an additional dimension to the signal processing. This intermediary modulation layer provides extra information that helps disambiguate targets with similar range-velocity characteristics, enabling the system to reliably distinguish between different targets that would otherwise be indistinguishable in conventional FMCW LIDAR.
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 rapid and accurate simultaneous measurement of range and velocity, reducing aliasing issues and improving the efficiency of target information acquisition in LIDAR systems.
Implementation Method 1
applying amplitude modulation (AM) or time of flight (TOF) signaling to frequency-modulated (FM) signals
Implementation Method 2
extract range and Doppler information
Data Source
AI summary
A light detection and ranging (LIDAR) system encodes a frequency modulation (FM) modulated signal with a time of flight (TOF) signal as a power and frequency modulated signal. The system can emit the power and frequency modulated signal and apply processing to a signal reflection to generate a target point set. The target point set processing can include frequency processing to generate target points based on range and Doppler information, and TOF processing to provide TOF range information. The LIDAR system can include a modulator to AM modulate an FM modulated light signal with an active modulator to provide the TOF signal information with the FM modulated signal as the power and frequency modulated signal.