LiDAR Pulse Encoding for Interference Resolution
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Solution Overview
Problem
Current LiDAR systems face challenges in accurately distinguishing between scattered light pulses from the same or different LiDAR systems, leading to incorrect object detection and interference, particularly in overlapping scanning regions, due to the inability to correctly pair pulses of light with their corresponding scattered light.
Innovation Solution
The implementation of a LiDAR system that encodes pulses of light with a sequence code, such as a pseudorandom bit sequence (PRBS), allowing for correlation with the sequence code to determine the correct pulse of scattered light, using a correlator to measure similarity and identify the correct pulse based on amplitude and time differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LiDAR systems transmit light pulses without encoding, then the system complexity is low, but the ability to distinguish scattered light from different sources is poor leading to false detection
Solution Approach 1:
The patent applies preliminary action by encoding light pulses with unique identification codes before transmission. This pre-encoding allows the system to distinguish between scattered light from different LiDAR sources, eliminating false detections without requiring complex real-time analysis during reception
Solution Approach 2:
The patent introduces an intermediary element - a unique identification code - that mediates between the transmitted light pulse and the scattered light detection. This code acts as a signature that enables the correlator to match received scattered light with the correct transmitted pulse, resolving the ambiguity in overlapping scanning regions
2Measurement precision
If LiDAR systems use encoding with correlator, then the accuracy of distinguishing scattered light is improved, but the processing time and computational load increase
Solution Approach 1:
By pre-encoding pulses with identification codes, the system prepares the data in advance for rapid correlation matching. This eliminates the need for complex real-time analysis during the critical reception phase, reducing processing time while maintaining high precision
Solution Approach 2:
The patent changes the parameter of light pulse encoding by modulating the light with unique identification codes. This transformation allows the correlator to efficiently match scattered light with transmitted pulses through simple correlation operations, achieving high precision with reduced computational complexity
3Productivity
If LiDAR systems transmit pulses at high frequency, then the productivity and scanning speed improve, but the interference between overlapping pulses increases
Solution Approach 1:
The patent applies preliminary action by encoding each transmitted pulse with a unique identification code before high-frequency transmission. This allows the system to process overlapping pulses at high speed while maintaining the ability to distinguish and correctly pair scattered light with the appropriate transmitted pulse through correlation matching
Solution Approach 2:
The unique identification code serves as an intermediary that enables the system to handle high-frequency pulse transmission without interference. The correlator uses this code to correctly associate scattered light with the specific transmitted pulse, even when multiple pulses overlap in time and space
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 enhances the accuracy of distance calculation by correctly identifying the pulse of scattered light corresponding to the transmitted pulse, reducing false object detection and interference, thereby improving the resolution and reliability of LiDAR systems in overlapping scanning regions.
Implementation Method 1
a light source, wherein the light source is configured to transmit a pulse of light to illuminate a surface of an object
Implementation Method 2
a modulator operable to encode the pulse of light in response to a signal from a sequence generator
Implementation Method 3
a light detector configured to detect scattered light from the surface of the object of the light pulse
Implementation Method 4
a correlator electrically coupled to the light detector, wherein the correlator is configured to correlate the scattered light with the sequence code and output a peak value associated with a time that the pulse of light is received
Implementation Method 5
determine a time difference between a time that pulse of light was transmitted and the time that the pulse of light is received; and calculate a distance to the surface of the object based on the time difference
Data Source
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AI summary
The present disclosure describes a system and method for encoding pulses of light for LiDAR scanning. The system includes a sequence generator, a light source, a modulator, a light detector, a correlator, and a microprocessor. The sequence generator generates a sequence code that the modulator encodes into a pulse of light from the light source. The encoded pulse of light illuminates a surface of an object, in which scattered light from the encoded light pulse is detected. The correlator correlates the scattered light with the sequence code that outputs a peak value associated with a time that the pulse of light is received. The microprocessor is configured to determine a time difference between transmission and reception of the pulse of light based on whether the amplitude of the peak exceeds the threshold value. The microprocessor calculates a distance to the surface of the object based on the time difference.