LiDAR Dynamic Range Expansion via Multi-Pulse Sequences
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Solution Overview
Problem
LiDAR systems face limitations in dynamic range due to the inverse proportionality of returned signal power with distance, requiring a range of 10^3-10^4, while typical photodetectors only offer a dynamic range of 10^2, leading to challenges in accurately measuring distances with precision.
Innovation Solution
A LiDAR system employing a sequence of pulse signals with varying peak power, where weaker signals precede stronger signals, allowing the system to operate within the dynamic range of the photodetector, and using a method to select and calculate distances based on the received signals within this range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a single high-power pulse is transmitted to detect distant objects, then the detection range is improved, but the returned signal from nearby objects exceeds the photodetector's dynamic range
Solution Approach 1:
The single high-power pulse is segmented into multiple pulses with different power levels. The transmitted signal is divided into a first pulse signal with lower power for nearby objects and a second pulse signal with higher power for distant objects, allowing the photodetector to measure both without saturation while maintaining detection range.
2Adaptability or versatility
If multiple pulse signals with different power levels are transmitted, then the dynamic range is expanded, but the system complexity increases
Solution Approach 1:
Multiple pulse signals with different power levels are merged into a single composite transmitted signal. The first and second pulse signals are combined in time and space, allowing the system to achieve expanded dynamic range using a single photodetector without requiring multiple detectors or complex switching mechanisms.
Solution Approach 2:
The pulse signals are transmitted in a periodic sequence with specific time intervals. The first pulse signal is transmitted at a first time and the second pulse signal at a second time, creating a periodic transmission pattern that allows the system to handle different power levels systematically while maintaining manageable complexity.
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 effectively expands the dynamic range of the LiDAR system to 10^4, enabling precise distance measurement by ensuring that at least one returned signal from each sequence falls within the detector's range, thus overcoming the limitations of standard photodetectors.
Implementation Method 1
The LiDAR system transmits a pulse signal, receives a returned signal, and calculates the distance to the object accordingly
Implementation Method 2
determine the distance by calculating the delay between the returned signal and the transmitted signal
Data Source
AI summary
A method for expanding a dynamic range of a light detection and ranging (LiDAR) system is provided. The method comprises transmitting, using a light source of the LiDAR system, a sequence of pulse signals consisting of two or more increasingly stronger pulse signals. The method further comprises receiving, using a light detector of the LiDAR system, one or more returned pulse signals corresponding to the transmitted sequence of pulse signals. The one or more returned pulse signals are above the noise level of the light detector. The method further comprises selecting a returned pulse signal within the dynamic range of the light detector, identifying a transmitted pulse signal of the transmitted sequence that corresponds to the selected returned pulse signal, and calculating a distance based on the selected returned signal and the identified transmitted signal.