Dynamic Optical Switch for Lidar Detector Saturation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lidar systems face saturation issues due to strong returns from near-range obscurants, which degrade measurements of farther targets by overwhelming the detector and causing electrical ringing and noise.
Innovation Solution
A receiver system that dynamically attenuates near-range laser light returns using a Fast Optical Switch (FOS) or Fast Variable Optical Attenuator (FVOA), controlled by a radio frequency (RF) waveform, to prevent saturation and enhance optical dynamic range, allowing both near and far-range returns to be observed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sufficient transmit power is used to observe distant targets, then the ability to detect far-range targets is improved, but near-range returns cause detector saturation and electrical ringing that degrade measurements
Solution Approach 1:
The patent applies dynamics by making the optical attenuator variable and controllable in real-time. The attenuator's transmission characteristic is dynamically adjusted based on the timing of returned light signals, allowing the system to adapt its attenuation level during the measurement window to prevent saturation while capturing weak distant target returns.
Solution Approach 2:
The patent implements preliminary action by pre-configuring the optical attenuator with a controlled transmission characteristic that anticipates the timing of near-range returns. The attenuator is programmed to provide high attenuation during expected near-range return windows before distant target returns arrive, preventing saturation in advance.
2Measurement precision
If the receiver gain is increased to detect weak far-range returns, then the sensitivity for distant targets is improved, but near-range returns overwhelm the detector and cause saturation
Solution Approach 1:
The patent applies local quality by creating different transmission characteristics for different time windows of the optical signal. The optical attenuator provides high attenuation for near-range return signals while providing low attenuation for far-range return signals, effectively treating different portions of the optical signal differently based on their temporal characteristics.
Solution Approach 2:
The patent introduces an optical attenuator as an intermediary component between the detector and the optical signals. This mediator selectively reduces the intensity of near-range returns through controlled attenuation while allowing weak far-range returns to pass through with minimal attenuation, enabling the detector to handle both signal types without saturation.
3Reliability
If a fixed optical attenuator is used to block near-range returns, then detector saturation is prevented, but the system cannot dynamically adjust to observe both near and far-range targets
Solution Approach 1:
The patent transforms a static attenuation system into a dynamic one by controlling the optical attenuator with time-varying signals. The controller adjusts the attenuator's transmission characteristic dynamically based on the expected timing of returns from different range zones, enabling the system to adaptively optimize performance for both near and far-range targets while preventing saturation.
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
The system effectively attenuates near-range returns, preventing detector saturation and enabling accurate detection of far-range targets by dynamically adjusting the transmission gating function, thereby improving measurement accuracy and reducing noise.
Implementation Method 1
The FOS may apply an RF voltage (e.g., the generated RF waveform) to produce a commensurate optical attenuation in a received signal
Data Source
AI summary
In one embodiment, a system includes a signal generator operable to generate a control waveform, an optical splitter operable to split light among first and second optical paths, and a detector in optical communication with the first optical path and operable to provide reference for the control waveform generation of the signal generator via the light of the first optical path. The system also includes an optical switch operable to attenuate a portion of the light of the second optical path based on the generated control waveform to detect a dynamic range signal.