LIDAR Analog Memory Reduces Power Consumption
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Solution Overview
Problem
Waveform LIDAR systems face power consumption issues due to the need for high-speed analog to digital converters, limiting the resolution of three-dimensional imaging, especially in on-orbit platforms where power is a constraint, and struggle with insufficient analog memory to store high-resolution time histories of returned signals.
Innovation Solution
Employing analog memories instead of high-speed analog to digital converters, using fewer ADCs and distributing them across multiple channels, and incorporating a distributed focal plane assembly with Geiger mode avalanche photodiodes and an angle-time-space LIDAR multiplexer to reduce power consumption and increase resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-speed analog to digital converters are used for each pixel, then measurement precision is improved, but power consumption increases excessively
Solution Approach 1:
The patent segments the signal processing function by separating analog memory storage from digital conversion. Each pixel channel has its own analog memory for continuous signal storage, while a shared ADC performs digital conversion only when needed. This segmentation allows high-time-resolution storage without requiring every pixel to have a power-hungry high-speed ADC operating continuously.
Solution Approach 2:
The patent implements a universal ADC that serves multiple pixel channels sequentially rather than dedicating a separate ADC to each pixel. The shared ADC reads out analog signals from multiple channels over time, providing digital conversion capability for all pixels while consuming far less total power than if each pixel had its own converter. This multi-functional approach maintains measurement precision while dramatically reducing power consumption.
2Measurement precision
If analog memory is increased per pixel, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent segments the memory function by providing dedicated analog memory in each pixel channel for continuous time-resolved signal storage, while separating the digital memory function to a centralized location. This segmentation allows each pixel to maintain high time resolution independently without requiring complex inter-pixel memory sharing or synchronization mechanisms.
Solution Approach 2:
The patent extracts the digital conversion and digital storage functions from the pixel level and relocates them to a centralized processing unit. By taking out the ADC and digital memory from each pixel, the design reduces per-pixel complexity while maintaining overall system capability through the shared conversion resource and centralized digital storage infrastructure.
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 significantly reduces power consumption while enabling higher resolution in three-dimensional imaging by allowing more analog memory and utilizing fewer, lower-speed ADCs, and allows for true volumetric imaging of diffuse targets with increased time resolution.
Implementation Method 1
Geiger mode avalanche photodiodes
Implementation Method 2
photon detector
Data Source
AI summary
LIDAR systems and methods are provided. More particularly, a distributed focal plane assembly is provided in which light collected by optical fibers is delivered to detectors on a separate substrate. Moreover, signals from detectors can be stored in analog memory on a different substrate from the detectors. Alternatively, light may be imaged onto detectors on one substrate and stored in analog memory on a different substrate. The detectors can be provided in a linear or one-dimensional array. A laser source can comprise a multiplexed laser source which provides a sequence of pulses separated in time and having different directions of propagation.