FMCW LiDAR AM-FM Detection for Fast Range and Velocity Sensing
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Solution Overview
Problem
Frequency-modulated continuous-wave (FMCW) LIDAR systems face limitations in quickly and efficiently obtaining target information due to the need to wait for upchirp and downchirp signals, and they 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 modulation (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 distinguish between range and Doppler information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If FMCW LIDAR systems use upchirp and downchirp signals to obtain target information, then measurement precision can be achieved, 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 measurement windows within each modulation period. This allows the system to perform multiple measurements in sequence, improving both speed and efficiency while maintaining precision through the structured periodic approach.
Solution Approach 2:
The patent uses amplitude modulation to pre-identify potential targets before full FMCW measurement. By modulating the signal amplitude at specific intervals, the system can quickly screen for targets and only perform complete range-velocity measurements on detected objects, significantly reducing overall acquisition time.
2Measurement precision
If FMCW LIDAR systems use upchirp and downchirp signals to measure range and velocity, then measurement capability is achieved, but short range targets are aliased leading to disambiguation issues
Solution Approach 1:
The patent segments the measurement process into distinct amplitude-modulated phases, allowing separate analysis of range and velocity information. By dividing the FMCW signal into amplitude-modulated segments, the system can disambiguate short-range targets from other signals, improving reliability while maintaining measurement precision.
Solution Approach 2:
The amplitude modulation serves as an intermediary signal that carries additional information about target range and velocity. This intermediate AM signal helps disambiguate short-range targets by providing independent verification data that resolves uncertainties in the primary FMCW measurement.
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 measurement of range and velocity, reducing aliasing issues and improving the efficiency of target information acquisition in LIDAR systems.
Implementation Method 1
a LIDAR system applies amplitude modulation (AM) or time of flight (TOF) signaling to frequency modulation (FM) signals
Implementation Method 2
frequency modulation (FM) signals
Implementation Method 3
amplitude modulation (AM) or time of flight (TOF) signaling
Implementation Method 4
simultaneous range and velocity measurement by processing reflection signals
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 processing can include an FM processing path to extract FM signal information, and an AM processing path to extract the TOF signal information.