LIDAR ADC Windowed Sampling for Low-Power Distance Sensing
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Solution Overview
Problem
LIDAR systems face challenges in efficiently determining object distance due to the low amplitude of received light pulses, which can be obscured by noise, requiring powerful lasers and complex circuitry that consumes significant power.
Innovation Solution
An integrated circuit with an analog-to-digital converter and receiver that operates during specific windows of high signal amplitude, enabling power conservation by reducing the need for continuous sampling and using slower, less power-hungry ADCs, while comparing signals to determine distance based on phase differences in continuous wave modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If continuous sampling is used to capture low amplitude received light pulses, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The patent implements periodic sampling of the received signal at specific time windows rather than continuous sampling. The ADC is activated only during predetermined time intervals when signal amplitude is expected to be highest, creating a periodic sampling pattern that reduces power consumption while maintaining measurement accuracy through strategic sampling at optimal moments
Solution Approach 2:
The patent uses preliminary distance estimates to predict optimal sampling windows. By calculating expected signal arrival times based on previous measurements, the system prepares and activates the ADC in advance at the most informative moments, ensuring high measurement precision without requiring continuous operation
2Measurement precision
If high sampling rates are used to capture signal details, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The patent employs periodic sampling at specific time windows rather than continuous high-rate sampling. By activating the ADC only during predetermined intervals when signal amplitude is expected to be maximum, the system achieves adequate measurement precision with significantly reduced sampling rates and power consumption
Solution Approach 2:
The patent applies partial sampling by capturing only the most informative portions of the signal at reduced sampling rates. Rather than continuously sampling at high rates, the system samples at lower rates during specific time windows, providing sufficient information for accurate distance estimation without the energy cost of full-rate continuous sampling
3Measurement precision
If powerful lasers are used to overcome noise, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The patent uses continuous wave modulation to continuously transmit modulated light signals rather than relying on high-power pulsed lasers. The continuous wave approach maintains a steady signal presence that can be detected against noise through phase comparison, eliminating the need for high peak power pulses while maintaining measurement precision
Solution Approach 2:
The patent replaces the mechanical approach of using high-power laser pulses with an optical modulation approach. Instead of increasing laser power to overcome noise, the system modulates a continuous wave signal and uses phase detection to extract distance information, substituting a power-intensive approach with a more efficient signal processing approach
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 estimation while reducing power consumption by selectively sampling during high information windows, allowing for more efficient operation of LIDAR systems.
Implementation Method 1
a source transmits light into a field of view and the light reflects off objects. Sensors receive the reflected light.
Data Source
AI summary
Described examples include an integrated circuit having an analog-to-digital converter operable to receive an input signal derived from a light signal and convert the input signal to a digital received signal, the analog-to-digital converter operable to receive the input signal during at least one window. The integrated circuit further has a receiver operable to receive the digital received signal, the receiver operable to determine a distance estimate of an object from which the light signal is reflected based on the digital received signal. In an example, the window locations are chosen to correspond to the locations of maximum slope in the signal.