With the growing number of autonomous vehicles equipped with pulsed scanning LIDAR operating close to each other at the same time, one pulsed scanning LIDAR might receive laser pulses from other pulsed scanning LIDAR. The reception of unwanted laser pulses from other pulsed scanning LIDAR is called mutual interference. Due to Lambertian reflectance of the laser pulse, a mixture of incoherent laser pulses arrives at each pixel from different paths apart from the direct path. This effects cause significant distortions in the estimation of depth, especially near corners and convex areas of the scene. We proposed a new pulsed scanning LIDAR, which measures a scene without mutual interference. The emitted pulse of each pixel is modulated pulses by direct sequence optical code division multiple access (DS-OCDMA) techniques. The modulated pulses include unique device identification number (ID), the pixel position in the line, and checksum. It emits the modulated pulse, and receives the return light to the detector. We modeled the entire of the pulsed scanning LIDAR operation in the RSoft OptSim and validated the results obtained in modeling and simulation.
The high intensity laser power beaming (HILPB) system is one of the most promising systems in the long-rang wireless power transfer field. The vertical multi-junction photovoltaic (VMJ PV) array converts the HILPB into electricity to power the load or charges a battery. The output power of a VMJ PV array depends mainly on irradiance values of each VMJ PV cells. For simulating an entire VMJ PV array, the irradiance profile of the Gaussian HILPB and the irradiance level of the VMJ PV cell are mathematically modeled first. The VMJ PV array is modeled as a network with dimension m*n, where m represents the number of VMJ PV cells in a column, and n represents the number of VMJ PV cells in a row. In order to validate the results obtained in modeling and simulation, a laboratory setup was developed using 55 VMJ PV array. By using the output power model of VMJ PV array, we can establish an optimal power transmission path by the receiver based on the received signal strength. When the laser beam from multiple transmitters aimed at a VMJ PV array at the same time, the received power is the sum of all energy at a VMJ PV array. The transmitter sends its power characteristics as optically coded laser pulses and powers as HILPB. Using the attenuated power model and output power model of VMJ PV array, the receiver can estimate the maximum receivable powers from the transmitters and select optimal transmitters.
Proc. SPIE. 10084, High Power Lasers for Fusion Research IV
KEYWORDS: Transmitters, Photovoltaics, Optical design, Solar energy, Solar cells, Energy transfer, Receivers, Power supplies, Error control coding, Laser optics, Pulsed laser operation, Wireless energy transfer, Channel projecting optics, Received signal strength
This paper presents the design and simulation of Laser power beaming (LPB) system that establishes an optimal power transmission path based on the received signal strength. LPB system is possible to transfer power from multiple transmitters to a single receiver to the characteristics of the laser and the solar panel. When the laser beam from multiple transmitters aimed at a solar panel at the same time, the received power is the sum of all energy at a solar panel. Our proposed LPB system consists of multiple transmitter and multiple receivers. The transmitter sends its power characteristics as optically modulated pulses and powers as high-intensity laser beams. Using the attenuated power level, the receiver can estimate the maximum receivable powers from the transmitters and select optimal transmitters. Throughout the simulation, we will verify that it is possible that different LPB receivers were achieved their required power by the optimal allocation of the transmitter among the different transmitters.
We designed a prototype for testing feasibility of a proposed light detection and ranging (LIDAR) system, which was designed to encode pixel location information in its laser pulses using the direct-sequence optical code division multiple access method in conjunction with a scanning-based microelectromechanical system (MEMS) mirror. The prototype was built using commercial o
-the-shelf optical components and development kits. It comprised of an optical modulator, an amplified photodetector, an MEMS mirror development kit, an analog-to-digital converter evaluation module, a digital signal processor with ARM evaluation kit and a Windows personal computer. The prototype LIDAR system has capable of acquiring 120 x 32-pixel images at 5 frames/s. We measured a watering pot to demonstrate the imaging performance of the prototype LIDAR system.
We propose a new hybrid 3D light detection and ranging (LIDAR) system, which measures a scene with 1280 x 600 pixels at a refresh rate of 60fps. The emitted pulses of each pixel are modulated by direct sequence optical code division multiple access (DS-OCDMA) techniques. The modulated pulses include a unique device identification number, the pixel position in the line, and a checksum. The LIDAR emits the modulated pulses periodically without waiting to receive returning light at the detector. When all the pixels are completely through the process, the travel time, amplitude, width, and speed are used by the pixel-by-pixel scanning LIDAR imager to generate point cloud data as the measured results. We programmed the entire hybrid 3D LIDAR operation in a simulator to observe the functionality accomplished by our proposed model.
The LIDAR scanner is at the heart of object detection of the self-driving car. Mutual interference between LIDAR scanners has not been regarded as a problem because the percentage of vehicles equipped with LIDAR scanners was very rare. With the growing number of autonomous vehicle equipped with LIDAR scanner operated close to each other at the same time, the LIDAR scanner may receive laser pulses from other LIDAR scanners. In this paper, three types of experiments and their results are shown, according to the arrangement of two LIDAR scanners. We will show the probability that any LIDAR scanner will interfere mutually by considering spatial and temporal overlaps. It will present some typical mutual interference scenario and report an analysis of the interference mechanism.