Advanced Techniques for LiDAR Interference Avoidance

Protecting a LiDAR device from external light sources that could interfere with its operation, by using proactive and reactive mitigation procedures. The proactive procedure involves operating the LiDAR to emit and detect light with specific timing, wavelengths, intensities, etc., and then adjusting those characteristics if external light is detected to match. The reactive procedure involves activating a shutter or varying emitted/detected light characteristics upon detecting external light. The LiDAR device may also include filters like interference, absorptive, adaptive, or spatial filters to block unwanted wavelengths or light angles.

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Techniques for reducing crosstalk between adjacent channels of a LiDAR system to ensure accurate detection. The techniques involve locking the wavelengths of the adjacent channel's light emitters to different values using feedback signals. For example, volume Bragg gratings or optical filters can be used to select and feedback a narrowband portion of each emitter's output. This prevents adjacent channels from interfering with each other's detection. The gratings/filters can also narrow the emitter bandwidth and reduce temperature dependence.

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A two-dimensional multi-beam LiDAR transmitter that uses an integrated optical phased array to steer multiple beams in two dimensions. The transmitter uses a Butler matrix network to generate N optical beams from an N-path FMCW signal. An optical beam expanding network and phase shifter array expands and phase-shifts the beams to enable two-dimensional beam steering. The beams are emitted by a multi-path grating-based optical antenna.

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An autonomous driving system using a lidar sensor that incorporates a diffractive optical element to separate beams from multiple laser sources into distinct points. This reduces crosstalk and sensor interference compared to conventional linear light source lidars. The system also varies laser intensity based on distance to improve sensing performance.

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A LiDAR system that uses an array of emitter/detector sets to cover a given field of view. The emitter/detector sets are configured to receive reflected light energy on unique coincident axes for each set. This provides reduced interference among emitters and from other LiDAR units compared to scanning LiDARs that emit on a single axis. The system can also use locally unique multi-bit emitter pulse sequences to further reduce interference.

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Laser receiving device for LiDAR systems that mitigates crosstalk and increases signal-to-noise ratio. The device has multiple parallel sensor-amplifier-collector-power supply channels for receiving laser echoes. It uses electromagnetic isolation between parallel sensors and amplifiers to prevent noise coupling. The parallel channels are arranged such that each forms an independent current loop, reducing crosstalk and improving signal quality compared to densely packed parallel channels without isolation. The device is used in LiDAR systems for autonomous vehicles and other applications.

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A LIDAR system that reduces signal interference among multiple sensors to improve reliability and accuracy of LIDAR systems in applications like self-driving cars or mapping. The method involves generating unique non-uniform pulse patterns for each sensor that can be distinguished from other sensors. Then, when processing the received LIDAR points, coherence filtering is applied to remove points that likely come from other sensors.

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LiDAR system with tunable filters to avoid interference from sunlight and other radiation sources. The system uses wavelength monitoring to track the laser's output wavelength and then tunes the filters in the receive path to match that wavelength. This filters out background light at other wavelengths while passing the laser light. This allows using narrower filters to reduce interference while still accommodating the laser's temperature-induced wavelength drift.

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Mitigating interference in mechanical scanning LiDAR systems. The method involves detecting interference from another non-co-located light source and adjusting the LiDAR scanning parameters to avoid interference. When interference is detected, the LiDAR system randomly modifies its scanning trajectory and timing to differentiate its light from the interfering source.

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LiDAR system design that improves heat dissipation and reduces electromagnetic interference for better performance and reliability. The LiDAR design separates functions onto multiple boards inside the housing - analog processing, digital processing, emitting, receiving, and interfaces - to isolate signals and prevent heat buildup. The emitting and receiving boards are shielded to reduce interference. Heat-generating components are attached to the housing for better dissipation.

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LiDAR system that cancels out Doppler frequency shifts due to target movement to improve object detection accuracy for autonomous vehicles. The system uses a reference channel that measures the unshifted Doppler signal. It then uses mathematical properties of signal mixing to shift the frequency of the imaging channels to cancel or reduce the Doppler shift. This allows extracting the Doppler-shifted information from the imaging channels while suppressing the Doppler shift.

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Target detection using radar, LiDAR, and camera sensors for applications like autonomous vehicles. The targets detected by radar and camera are used as anchor points to generate 3D regions of interest. The LiDAR point cloud and camera image are projected onto the regions of interest and fused. This fused image is processed to output the final detection result.

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Lidar (Light Detection and Ranging) is a sensing technology that uses laser light to measure distances. Lidar systems can experience interference when multiple lidars are used in the same area, causing crosstalk between their signals. To mitigate this interference, the lidar transmits laser pulses with randomized timing intervals. This disrupts the correlation between the lidar's own transmit and receive times versus other lidar echoes. By identifying echoes with lower correlation due to the randomized timing, interference can be detected and filtered out.

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Interference detection and/or mitigation for pulsed LIDAR systems to ensure accurate object detection and prevent false targets. The method involves combining detector signals from multiple pulses at the same delay time to evaluate if they represent true target reflections. If the combined signal exceeds a threshold, it is considered a valid target. If the variation between the signals exceeds a threshold, it is considered interference.

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Enhancing accuracy and reliability of LiDAR devices for applications like autonomous vehicles through improved scanning, detection, and control methods. The methods include scanning selected regions, refining regions based on detection results, and using sensors to monitor and adjust scanning. This allows focusing resources on areas of interest and improving accuracy.

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LiDAR system for vehicles that can detect and locate interference sources on its window that can impair performance. The system uses secondary detectors positioned on the window to capture scattered light from defects like scratches, dirt or drops inside the window. It compares the scattered light intensity detected by the secondary detectors to locate and identify interference sources.

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