FM LIDAR Scanning for Long-Range Detection With Low Interference
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Solution Overview
Problem
Existing LIDAR systems for autonomous vehicles face challenges in accurately detecting objects at various distances and velocities, especially in scenarios with low reflectivity objects and interference from bright sunlight or self-interference.
Innovation Solution
The implementation of a frequency-modulated (FM) LIDAR sensor system that uses frequency or phase modulation to encode optical signals, allowing for more accurate detection of objects by determining their location and velocity through the Doppler effect, while also minimizing interference from crosstalk and self-interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional LIDAR systems are used, then basic range detection is achieved, but measurement precision deteriorates due to interference from bright sunlight and self-interference
Solution Approach 1:
The patent applies frequency modulation to the laser beam, changing the frequency parameter of the light signal. By modulating the frequency of the laser source and detecting the frequency shift of returned signals, the system can distinguish true reflections from ambient sunlight interference and self-interference, thereby improving measurement precision in challenging lighting conditions.
2Quantity of substance
If detection range is increased to detect objects at greater distances, then productivity is improved, but measurement precision deteriorates due to signal weakening
Solution Approach 1:
The system uses frequency modulation of the laser source, allowing detection of frequency shifts in weak return signals. This enables accurate velocity and range measurement even when objects are at greater distances, as the frequency-based detection method remains effective regardless of signal intensity attenuation over distance.
Solution Approach 2:
The LIDAR system continuously transmits modulated laser beams and receives returned signals, using the frequency information from multiple measurements to track and determine object velocity and range. This feedback mechanism allows the system to maintain measurement precision across varying distances by continuously refining its detection based on returned signal characteristics.
3Measurement precision
If velocity detection capability is enhanced, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent utilizes frequency modulation of the laser source and detects frequency shifts in returned signals to determine object velocity. This approach leverages the Doppler effect, where the frequency of reflected light changes based on the relative velocity between the LIDAR system and the target object, enabling velocity measurement without additional complex hardware.
Solution Approach 2:
The system replaces complex mechanical velocity measurement systems with an optical frequency-based approach. By using frequency-modulated continuous wave (FMCW) LIDAR, velocity information is extracted from the frequency shift of light signals rather than requiring mechanical motion sensors or multiple complex sensor arrays, thereby reducing overall device complexity while maintaining high velocity measurement precision.
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
The FM LIDAR system enhances the ability to detect objects at greater distances and velocities, providing more accurate data with reduced hardware and software requirements, thus improving the reaction time and safety of autonomous vehicles.
Implementation Method 1
frequency or phase modulation to encode optical signals
Implementation Method 2
laser source configured to generate a beam
Implementation Method 3
optic module configured to collimate the beam
Implementation Method 4
one or more scanning optics configured to receive the collimated beam from the optic module and output the collimated beam
Implementation Method 5
light sensor configured to output a signal based on the beam received by the mirror
Implementation Method 6
determining their location and velocity through the Doppler effect
Data Source
AI summary
A light detection and ranging (LIDAR) system includes a transmitter, a first receiver, a second receiver, and one or more processors. The transmitter is configured to output a transmit beam. The first receiver is positioned on a first side of the transmitter and is configured to receive a first component of a return beam from reflection of the transmit beam by an object. The second receiver is positioned on a second side of the transmitter and is configured to receive a second component of the return beam. The one or more processors are configured to determine at least one of a range to the object or a velocity of the object and control operation of the autonomous vehicle based on the at least one of the range or the velocity.