Multi-Detector LiDAR Pulse Discrimination for Range Aliasing
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Solution Overview
Problem
Bistatic LIDAR systems face issues with parallax, range aliasing, and cross-talk due to the physical displacement of emitters and receivers, leading to detection challenges at both short and long ranges, and increased signal noise ratios.
Innovation Solution
Implementing a multi-detector LIDAR system with photodetectors oriented at varying angles to cover different detection ranges, selectively turning on and off detectors based on time intervals and bias voltage levels to mitigate these issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single receiver is used to detect return light from an emitter, then the device complexity is reduced, but range aliasing and cross-talk problems occur making it difficult to determine which emitted light pulse the detected return light originated from
Solution Approach 1:
The single receiver is segmented into multiple receivers (first receiver and second receiver), each dedicated to detecting return light from specific light pulses (first light pulse and second light pulse). This segmentation allows the system to maintain low overall complexity while eliminating range aliasing by assigning specific detection responsibilities to each receiver, thereby preserving pulse origin identification information.
2Speed
If the emitter and receiver are physically displaced relative to each other in a bistatic LIDAR system, then the system can operate at very short distances, but parallax problems occur because the light emitted by the emitter and received by the detector may not travel along parallel paths
Solution Approach 1:
The system segments the detection function across multiple receivers positioned at different locations relative to the emitter. Each receiver detects return light within its specific field of view, allowing the system to operate at very short distances while maintaining measurement precision through proper geometric configuration and selective detection.
Solution Approach 2:
Each receiver is configured with specific local properties (field of view, detection range, orientation) optimized for its position relative to the emitter. The first receiver is optimized for detecting return light from the first light pulse, while the second receiver is optimized for the second light pulse, allowing accurate distance measurements despite physical displacement between emitter and receivers.
3Area of stationary object
If a wide field of view is used to handle both short and long-range detections, then the detection range is improved, but the amount of background light detected by the receiver increases without increasing the amount of light emitted by the emitter, which significantly increases the signal to noise ratio of the receiver
Solution Approach 1:
The wide field of view is segmented across multiple receivers, each with a narrower individual field of view. This segmentation allows the system to maintain comprehensive coverage while each receiver detects less background light, thereby improving the signal to noise ratio for each detection channel.
Solution Approach 2:
Each receiver is configured with local detection properties optimized for its specific orientation and field of view. By distributing the wide field of view coverage across multiple receivers with tailored detection characteristics, the system achieves comprehensive range coverage while maintaining low background light levels and high signal to noise ratios at each detection point.
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
Enhances detection capabilities across varying ranges, reduces signal noise, and effectively distinguishes between return light pulses, thereby improving data collection and reducing power consumption.
Implementation Method 1
an emitter device of a LIDAR system emits a first light pulse into an environment
Implementation Method 2
a first detector device and a second detector device of the LIDAR system detect the return light
Data Source
AI summary
A method including emitting, by a light emitter, a first light pulse at a first time; activating a first light detector and a second light detector with different fields of view, emitting, by the light emitter, a second light pulse at a second time; receiving return light by the first light detector or the second light detector at a third time; and determining, based on the return light being detected by the first light detector or the second light detector, whether the return light is based on the first light pulse or the second light pulse when the first light pulse and second light pulse are simultaneously traversing an environment for a period of time.