Lidar Window Blockage Detection via Segmented Receiver
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Solution Overview
Problem
Lidar systems face challenges in accurately detecting and determining the distance of downrange targets due to blocking contaminants on the sensor window, which scatter or absorb the output beam instead of reaching the target.
Innovation Solution
The implementation of additional detectors in the lidar system's receiver to detect light scattered by blocking contaminants on the sensor window, allowing for the identification and characterization of these contaminants and enabling appropriate responses such as cleaning or window replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional detectors are added to detect scattered light from blocking contaminants, then the ability to detect window blockage is improved, but the device complexity increases
Solution Approach 1:
The receiver is segmented into multiple specialized detectors: a first detector for downrange targets and a second detector for window blockage. This segmentation allows each detector to be optimized for its specific function, improving overall system reliability while maintaining manageable complexity through functional separation.
Solution Approach 2:
The patent introduces an intermediary processing approach where the second detector captures scattered light from blocking contaminants, and a processor analyzes the ratio of signals from both detectors to identify blockage. This intermediary analysis layer resolves the contradiction by providing reliable blockage detection without requiring a completely redesigned receiver structure.
2Device complexity
If the lidar system uses a single detector for all detection purposes, then the device complexity is reduced, but the measurement precision for distinguishing blockage from nearfield objects deteriorates
Solution Approach 1:
Different detectors are assigned to different spatial regions and detection purposes: the first detector focuses on downrange targets while the second detector specifically monitors the region near the sensor window for blockage. This local quality assignment enables precise discrimination between blockage and nearfield objects by analyzing the spatial distribution and characteristics of detected light.
Solution Approach 2:
The patent adds a new detection dimension by introducing a second detector that specifically measures scattered light from blockage. This creates an additional measurement dimension (blockage detection channel) that is independent from the primary target detection channel, enabling precise discrimination between blockage and nearfield objects through multi-dimensional signal analysis.
3Device complexity
If the lidar system operates without blockage detection capability, then the device complexity remains low, but the accuracy of distance measurement to downrange targets deteriorates when blockage is present
Solution Approach 1:
The second detector provides feedback about window blockage conditions to the control system. When blockage is detected through analysis of the scattered light signal, the system can compensate for the blockage effect or alert the operator, thereby maintaining accurate distance measurements to downrange targets even in the presence of blockage.
Solution Approach 2:
The second detector continuously monitors for window blockage before it significantly degrades the accuracy of downrange target measurements. By detecting blockage early through scattered light analysis, the system can take preliminary actions such as cleaning the window or adjusting measurement parameters to maintain measurement precision.
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 lidar systems by effectively detecting and mitigating the impact of blocking contaminants, ensuring reliable operation and maintaining the system's ability to accurately map its environment.
Implementation Method 1
The light source emits light toward a target which scatters the light, and some of the scattered light is received back at the receiver
Implementation Method 2
the lidar system may determine the distance to the target based on the time of flight for a pulse of light emitted by the light source to travel to the target and back to the lidar system
Implementation Method 3
detect light scattered by blocking contaminants on the sensor window
Data Source
AI summary
A scanner is configured to scan the emitted light through a window. A first detector is positioned to receive at least a portion of the emitted light scattered by a downrange target. A second detector is positioned to receive at least a portion of the emitted light scattered by a window obscurant. A third detector is positioned to receive at least a portion of the emitted light scattered by a close obscurant located within a distance range that is between a minimum detection distance associated with the first detector and a maximum detection distance associated with the second detector. A processor is configured to determine whether an obscurant located closer to the window than the minimum detection distance associated with the first detector is detected based on one or more signal properties of the second detector and one or more signal properties of the third detector.