Lidar Peak Detection Using TDC and MPPC for Wider Dynamic Range
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Solution Overview
Problem
Existing LIDAR sensors for autonomous driving vehicles face high costs due to expensive high-speed analog-to-digital converters and have insufficient dynamic range, particularly when detecting reflections from distant or irregular surfaces.
Innovation Solution
The use of a low-cost time-to-digital conversion device and a multi-pixel photon counter, such as an array of single photon avalanche diodes, to measure the peak magnitude and time of reflection of a laser beam, allowing for efficient navigation by correlating intensity and time-of-flight with object attributes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-speed analog-to-digital converters are used to measure peak location and magnitude, then measurement precision is improved, but device cost increases
Solution Approach 1:
The patent replaces expensive high-speed ADCs with cheaper alternative components including time-to-digital converters and multi-pixel photon counters. These lower-cost components achieve the necessary measurement precision for LIDAR applications without the high cost of traditional high-speed ADCs, directly addressing the cost issue while maintaining measurement capability
Solution Approach 2:
The patent changes the measurement approach by using time-to-digital conversion instead of direct analog-to-digital conversion of the reflected signal. This parameter change in the measurement methodology allows using less expensive components while achieving equivalent or better precision for determining peak location and magnitude
2Reliability
If traditional detectors like PIN diodes and avalanche photodiodes are used, then detection capability is achieved, but dynamic range is insufficient
Solution Approach 1:
The patent divides the detection function across multiple specialized components: time-to-digital converters for timing measurement and multi-pixel photon counters for intensity measurement. This segmentation allows each component to be optimized for its specific function, achieving both reliable detection and sufficient dynamic range that traditional single detectors cannot provide
Solution Approach 2:
The patent introduces time-to-digital converters as an intermediary component between the reflected signal and the measurement system. This intermediary converts timing information into a form that can be processed with greater dynamic range, enabling the system to handle both weak distant reflections and strong nearby reflections effectively
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 reduces the cost and improves the dynamic range of LIDAR sensors, enabling effective detection of obstacles and environment mapping with enhanced accuracy and efficiency for autonomous driving vehicles.
Implementation Method 1
a multi-pixel photon counter, such as an array of single photon avalanche diodes, to measure the peak magnitude
Implementation Method 2
time-to-digital conversion device and a multi-pixel photon counter, such as an array of single photon avalanche diodes, to measure the peak magnitude and time of reflection
Data Source
AI summary
A LIDAR scanning system uses a combination of a time-to-digital conversion (TDC) device and a multi-pixel photon counter (MPPC) to determine the peak location (time) and magnitude of a reflection of a laser beam off of an object. A configurable trigger threshold of the TDC indicates that a sufficient number of MPPC pixels have triggered that the peak detection module should begin sampling and storing MPPC counts of triggered pixels. When the light received from the reflected laser beam falls below the trigger threshold of the TDC, the MPPC stops sampling the MPPC counts. The peak magnitude of the reflection of the laser beam is determined from the highest sample count of the MPPC. A time at which the peak magnitude occurred is determined as the midpoint of TDC trigger points. The peak magnitude MPPC count is correlated to an intensity value.