Multi-Channel FMCW LiDAR Beam Steering for Simultaneous Range and Velocity
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Solution Overview
Problem
Existing FMCW LIDAR systems face challenges in simultaneously measuring distance and velocity due to the need for separate measurements, which can be time-consuming, and require complex beam steering mechanisms that increase system cost and complexity.
Innovation Solution
A multi-channel FMCW LIDAR system using a single beam steering module and integrated photonic chip with multiple laser channels, enabling simultaneous beam scanning and velocity measurement through complementary frequency sweeps, reducing complexity and cost by integrating most components on-chip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple frequency-modulated lasers with complementary frequency sweeps are used, then measurement speed is enhanced and velocity can be measured simultaneously with range, but system complexity increases due to requiring multiple scanning elements to capture larger field of view
Solution Approach 1:
The patent combines multiple laser channels with complementary frequency sweeps into a single integrated system that shares scanning elements. Multiple laser beams are multiplexed and scanned simultaneously across the target environment using a single beam steering module, eliminating the need for separate scanning elements for each laser channel and reducing overall system complexity while maintaining high measurement speed
Solution Approach 2:
The single beam steering module serves multiple functions by scanning multiple laser channels simultaneously. This universal scanning mechanism captures data from all laser channels across the field of view in a single operation, enabling both range and velocity measurements without requiring dedicated scanning elements for each laser channel
2Device complexity
If a single beam steering module is used for multiple laser channels, then system complexity and cost are reduced, but beam steering capability for multiple channels simultaneously must be achieved
Solution Approach 1:
The patent segments the beam steering function by assigning different scanning patterns or time slots to different laser channels within a single beam steering module. This allows each laser channel to be steered independently while sharing the same physical scanning mechanism, achieving multi-channel capability without requiring separate steering systems for each channel
Solution Approach 2:
The system uses periodic scanning patterns where multiple laser channels are scanned in a coordinated sequence. The beam steering module cycles through different scanning trajectories for different channels, enabling simultaneous coverage of the field of view while maintaining simple hardware architecture through time-multiplexed scanning
3Measurement precision
If successive measurements are used to obtain velocity, then measurement accuracy can be maintained, but measurement time is doubled compared to single measurement methods
Solution Approach 1:
The patent performs preliminary frequency modulation with complementary sweeps on multiple laser channels before the measurement process. By pre-configuring the frequency patterns (positive and negative sweeps) on different channels, the system enables simultaneous extraction of both range and velocity information from the reflected signals without requiring successive measurements, thus reducing measurement time while maintaining accuracy
Solution Approach 2:
The system uses the frequency-modulated signals as an intermediary carrier that encodes both range and velocity information simultaneously. By analyzing the frequency shift and time delay of these modulated signals, the system extracts both parameters in a single measurement process, eliminating the need for separate successive measurements and reducing total measurement time
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 system achieves efficient simultaneous measurement of range and velocity without successive measurements, reducing system complexity and cost by utilizing a single beam steering module and integrated photonic chip.
Implementation Method 1
FMCW lasers may be modulated to have a linear frequency sweep from lower frequency to higher frequency, and then from higher frequency to lower frequency, in a triangular fashion
Implementation Method 2
A laser module with N laser diodes, where N is an integer greater than or equal to 2, is coupled to a photonics assembly
Implementation Method 3
Beam steering modules may scan laser beams across a target environment
Implementation Method 4
A coherent receiver module at the proximity of optical antennas eliminates the need of fiber circulators
Implementation Method 5
Moving targets shift a reflected signal's frequency proportional to the velocity of the target due to the Doppler effect, which can be measured simultaneously
Implementation Method 6
The multi-channel FMCW LIDAR can be implemented on a single integrated photonic chip with multi-channel transceivers, where most of the discrete components are replaced with on-chip components
Data Source
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AI summary
A FMCW LIDAR system for simultaneous beam scanning of the target environment. The system can include a photonics assembly couplable to a beam steering module. The photonics assembly is configured to receive a frequency modulated laser beam and can include an optical splitter and a coherent receiver. The optical splitter can be configured to optically split the frequency modulated laser beam into a local laser beam and a target laser beam, deliver the target laser beam to the beam steering module, and receive the target laser beam reflected by a target from the beam steering module. The coherent receiver can be configured to mix the local laser beam and the target laser beam to produce an output signal.