Suitable Combination of Direct Intensity Modulation and Spreading Sequence for LIDAR with Pulse Coding

Kim, Gunzung; Park, Yongwan

doi:10.3390/s18124201

Cited by 19 publications

(4 citation statements)

References 54 publications

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“…Optimal operation in the CDMA mode, in terms of imaging speed, is achieved when the time needed to generate one sequence roughly reaches the time step of the scanning module. Previous implementations with full CDMA sequencing using micro-electromechanical systems (MEMS) scanners for lidar imaging 33 , 36 did not necessarily account for this issue, which resulted in time sequences reaching the millisecond range. Here the extremely fast megahertz scanning speed of the AOD diminishes by 2 or 3 orders of magnitude the time available to generate the sequences.…”

Section: Comparison Between the Imaging Techniquesmentioning

confidence: 99%

“…35 In this scheme, strongly inspired by code division multiple access (CDMA) multiplexing technique from telecommunication theory, different pixels are modulated with different sequences, and the sequence family satisfies orthogonality conditions to avoid cross talk between pixels. From this point, research on this topic has focused on comparing and optimizing the modulation sequences, 36,37 proposing more complex sequence generation using wavelength division, 38 implementing hardware solutions to optimize the processing time, 39 or on considering this technique to ensure the robustness to interference from other lidars. 40 As for the experimental demonstration of this technique, implementations have only been made in kilohertz scanning devices, 41 hence using codes that were not compatible with fast scanning.…”

Section: Introductionmentioning

confidence: 99%

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Overcoming the limitations of 3D sensors with wide field of view metasurface-enhanced scanning lidar

et al. 2023

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Lidar, a technology at the heart of autonomous driving and robotic mobility, performs 3D imaging of a complex scene by measuring the time of flight of returning light pulses. Many technological challenges, including enhancement of the observation field of view (FoV), acceleration of the imaging frame rate, improvement of the ambiguity range, reduction of fabrication cost, and component size, must be simultaneously addressed so that lidar technology reaches the performance needed to strongly impact the global market. We propose an innovative solution to address the problem of wide FoV and extended unambiguous range using an acousto-optic modulator that rapidly scans a large-area metasurface deflector. We further exploit a multiplexing illumination technique traditionally deployed in the context of telecommunication theory to extend the ambiguity range and to drastically improve the signal-to-noise ratio of the measured signal. Compacting our metasurface-scanning lidar system to chip-scale dimension would open new and exciting perspectives, eventually relevant to the autonomous vehicles and robotic industries.

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Section: Comparison Between the Imaging Techniquesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Overcoming the limitations of 3D sensors with wide field of view metasurface-enhanced scanning lidar

et al. 2023

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“…However, coding techniques in optics can only use the presence of light, limiting them to represent only zeros (''0''s) and positives (''+1''s), unlike RF which can represent negative numbers (''−1''s). To represent a single bit in optics, a very long pulse stream is required which results in a long time to transmit the pulse stream [12], [18]. This LiDAR uses a pulse stream coded with OOFDMA to encode information into a very short length and then carried on multiple wavelengths from dense wavelength-division multiple-access (DWDMA) recommendations.…”

Section: Oofdma-based Lidar a Design Conceptmentioning

confidence: 99%

Coded Pulse Stream LiDAR Based on Optical Orthogonal Frequency-Division Multiple Access

Kim,

Ashraf,

Eom

et al. 2023

IEEE Access

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In future mobility, robust obstacle detection is imperative for autonomous vehicles, fostering a reliance on vision-based data and the emergence of light detection and ranging (LiDAR) as a pivotal sensor. Despite challenges of cost and novelty, LiDAR's unique capabilities find favor among automakers, except Tesla. Offering 3D imaging with superior resolution than radar, LiDAR holds potential significance as a perception sensor for safe and efficient transportation. Its 3D distance measurement using laser pulses and waveform analysis is vital for obstacle detection in autonomous vehicles. Techniques like scanning and flash LiDAR optimize point cloud acquisition, albeit with challenges in balancing resolution and frame rates. Because LiDAR measures the distance to an object using the time-of-flight, the idle listening time required to detect reflected waves increases in proportion to the maximum distance. Both, lateral angular resolution and frame rates are dependent on this idle listening time. Lateral angular resolution impacts LiDAR's ability to detect objects. This study proposes an optical orthogonal frequency-division multiple access (OFDMA) LiDAR with a coded pulse technique to enhance the detection accuracy of objects. Simulation results demonstrate that the proposed OFDMA LiDAR overcoming false positives and mutual interference through pulse stream LiDARs and strategic approaches is crucial in LiDAR's integration into future mobility systems. INDEX TERMSAutonomous vehicles, LiDAR, optical communication, optical OFDMA, time-of-flight, discrete Hartley transform.

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“…DS-OCDMA has been designed to provide multiple and simultaneous access to optical systems. DS-OCDMA has been examined already in environments requiring an address or user identification in various optical applications [37][38][39][40][41][42][43]. The PCI transmitted from a PTX comprises DS-OCDMAencoded data designed to make one PCI orthogonal to the others, given that different sets of information are simultaneously sent from multiple PTXs.…”

Section: Power Transmitter (Ptx)mentioning

confidence: 99%

Optimal Path Configuration with Coded Laser Pilots for Charging Electric Vehicles Using High Intensity Laser Power Beams

et al. 2021

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Wireless power transmission (WPT) for wireless charging has been gaining wide attention as a promising approach to miniaturizing the battery size and increasing the maximal total range of an electric vehicle (EV). With an appropriate charging infrastructure, WPT holds great potential to accelerate the acceptance of EVs through users’ higher satisfaction, reducing EV cost, and increasing the driving range and capability. A WPT system based on high-intensity laser power beaming (HILPB) provides an optimal solution for wirelessly charging electric vehicles from a distance of several meters. Despite a large number of WPT approaches, the problem of optimal path configuration for charging EV remains an unexplored area. This paper proposes a method to determine the optimal power transmission path in environments where multiple power transmitters (PTXs) and power receivers (PRXs) are operated simultaneously. To this end, we modeled the HILPB power that reaches a PRX equipped with a photovoltaic (PV) array and validated the model by simulating the WPT process in an environment with multiple PTXs and PRXs using a direct-sequence optical code division multiple access (DS-OCDMA) system. In the simulation environment, upon receiving a request from a PRX, a PTX sent its power channel information through optically encoded laser pulses using each available wireless power channel (WPC). The PRX calculated the maximum deliverable power of a PTX and WPC based on the received channel power indicator of the incident laser beam. Based on the calculation results, it selected the optimal PTX and WPC for its maximum power requirement (MPQ). The MPQ of each PRX was satisfied by applying the algorithm for selecting the PTX according to the alignment and characteristics of the PTXs and PRXs. We modeled a power reception model of the PRX based on a PV array using coded laser pilots and validated it through experimentation. We discussed some algorithms that select the most suitable PTX among several PTXs for which several EVs receive the power it needs.

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Suitable Combination of Direct Intensity Modulation and Spreading Sequence for LIDAR with Pulse Coding

Cited by 19 publications

References 54 publications

Overcoming the limitations of 3D sensors with wide field of view metasurface-enhanced scanning lidar

Overcoming the limitations of 3D sensors with wide field of view metasurface-enhanced scanning lidar

Coded Pulse Stream LiDAR Based on Optical Orthogonal Frequency-Division Multiple Access

Optimal Path Configuration with Coded Laser Pilots for Charging Electric Vehicles Using High Intensity Laser Power Beams

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