FMCW LiDAR FIRE-RA System Optical Correlation
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Solution Overview
Problem
Existing FMCW LiDAR systems face challenges in scalability and integration in compact environments due to high power consumption and the need for complex, high-speed digital signal processing systems.
Innovation Solution
The proposed FMCW LiDAR system incorporates a Frequency Information Rapid Extraction for Ranging Applications (FIRE-RA) system, which uses a modulation source with two outputs to sweep in phase across the required bandwidth, and a balanced photo detector to process interference signals, eliminating the need for FFTs and reducing computational power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional FMCW LiDAR systems use high-speed digital signal processing with FFTs, then measurement precision for distance and velocity is improved, but device complexity and power consumption increase significantly
Solution Approach 1:
The patent extracts and eliminates the need for FFT-based digital signal processing from the FMCW LiDAR system. By using a simplified correlation-based approach with a modulation source that sweeps in phase across the required bandwidth, the system removes the complex computational burden while maintaining measurement capabilities for distance and velocity extraction.
Solution Approach 2:
The patent replaces the traditional electronic/digital signal processing system (requiring high-speed ADCs and FPGA FFT processing) with an optical correlation approach. The modulation source and balanced photo detector create an optical interference pattern that directly encodes distance and velocity information, substituting complex electronic computation with optical physics-based measurement.
2Productivity
If traditional FMCW LiDAR systems use high-power FPGA chips for signal processing, then productivity and data processing capability are improved, but use of energy increases significantly
Solution Approach 1:
The patent removes the high-power FPGA chip and its associated FFT processing workload from the system. By using a correlation-based method with a phase-sweeping modulation source, the system extracts only the necessary information (distance and velocity) without requiring the computational horsepower of high-end FPGAs, thereby dramatically reducing power consumption.
Solution Approach 2:
The patent changes the operating parameters of the modulation source to sweep in phase across the required bandwidth rather than using fixed-frequency modulation. This parameter change enables the system to extract both distance and velocity information through optical correlation, eliminating the need for high-power digital signal processing and reducing overall power consumption to approximately 2 W.
3Ease of manufacture
If FMCW LiDAR systems are designed for scalability and compact integration, then ease of manufacture and device size are improved, but measurement precision may be compromised
Solution Approach 1:
The patent replaces complex digital signal processing hardware with an optical correlation system that uses a modulation source sweeping in phase across the required bandwidth. This substitution enables compact integration and scalability while maintaining 5 cm total distance accuracy, as the optical interference pattern directly encodes distance information without requiring complex electronic processing chains.
Solution Approach 2:
The patent creates a universal FMCW LiDAR architecture where the modulation source and balanced photo detector perform multiple functions: distance measurement, velocity measurement, and coherent detection. This multi-functionality in a single integrated system enables compact design and ease of manufacture while maintaining measurement precision, as the same optical correlation process extracts all required information simultaneously.
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 solution enables a scalable, low-power FMCW LiDAR system that can efficiently extract radial velocity and distance information, achieving 5 cm total distance accuracy and 0-156 mph radial speed range, while reducing power consumption to approximately 2 W.
Implementation Method 1
an electro-optic modulator configured to modulate a laser generated by a laser source
Implementation Method 2
a balanced photo detector configured to process an interference signal of a local copy of the laser coupled with a signal of the laser returned from a target
Implementation Method 3
the modulation source is configured to sweep in phase across a required bandwidth for the electro-optic modulator and the balanced photo detector
Implementation Method 4
output distance and speed data for the target according to the processed interference signal
Data Source
AI summary
A frequency modulated continuous wave LiDAR system is disclosed that may be scalable and integrated in compact and demanding environments. The improved system of the present disclosure includes: an electro-optic modulator configured to modulate a laser generated by a laser source; a balanced photo detector configured to process an interference signal of a local copy of the laser coupled with a signal of the laser returned from a target and output a beatnote signal; a modulation source with two outputs, and a Frequency Information Rapid Extraction for Ranging Applications (“FIRE-RA”) system to receive the interference signal from the balanced photo detector, process the interference signal with a signal from one of the two outputs of the modulation source for the balanced photo detector, and output distance and speed data for the target according to the processed interference signal.