Beam Formation and Vernier Steering Off of a Rough Surface

Wavefront shaping can refocus light after it reflects from an optically rough surface. One proposed use case of this effect is in indirect imaging; if any rough surface could be turned into an illumination source, objects out of the direct line of sight could be illuminated. In this paper, we demonstrate the superior performance of a genetic algorithm compared to other iterative feedback-based wavefront shaping algorithms in achieving reflective inverse diffusion for a focal plane system. Next, the ability to control the pointing direction of the refocused beam with high precision over a narrow angular range is demonstrated, though the challenge of increasing the overall scanning range of the refocused beam remains. The method of beam steering demonstrated in this paper could act as a vernier adjustment to a coarse adjustment offered by another method.

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A Novel LOS Decision Technique Reflecting 3D DTED for Modeling an Electronic Warfare Environment

Applied Sciences ◽

10.3390/app11010409 ◽

2021 ◽

Vol 11 (1) ◽

pp. 409

Author(s):

Jaejoong Lee ◽

Chiho Lee ◽

Hyeon Hwi Lee ◽

Kyung Tae Park ◽

Hyun-Kyo Jung ◽

...

Keyword(s):

Interpolation Method ◽

Three Dimensional ◽

Superior Performance ◽

Line Of Sight ◽

Electronic Warfare ◽

Decision Algorithm ◽

Elevation Data ◽

The Republic ◽

Point Distance ◽

Terrain Elevation

A new line-of-sight (LOS) decision algorithm applicable to simulation of electronic warfare (EW) is developed. For accurate simulation, the digital terrain elevation data (DTED) of the region to be analyzed must be reflected in the simulation, and millions of datasets are necessary in the EW environment. In order to obtain real-time results in such an environment, a technology that determines line-of-sight (LOS) quickly and accurately is very important. In this paper, a novel algorithm is introduced for determining LOS that can be applied in an EW environment with three-dimensional (3D) DTED. The proposed method shows superior performance as compared with the simplest point-to-point distance calculation method and it is also 50% faster than the conventional interpolation method. The DTED used in this paper is the data applied as level 0 for the Republic of Korea, and the decision of the LOS at approximately 1.8 million locations viewed by a reconnaissance plane flying 10 km above the ground is determined within 0.026 s.

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A Localization Algorithm Research to Eliminate the Indoor NLOS Error

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.989-994.2232 ◽

2014 ◽

Vol 989-994 ◽

pp. 2232-2236 ◽

Cited By ~ 1

Author(s):

Jia Zhi Dong ◽

Yu Wen Wang ◽

Feng Wei ◽

Jiang Yu

Keyword(s):

Indoor Environment ◽

Arrival Time ◽

Channel Model ◽

Indoor Positioning ◽

Superior Performance ◽

Line Of Sight ◽

Localization Algorithm ◽

Positioning Accuracy ◽

Software Simulation ◽

Positioning Algorithm

Currently, there is an urgent need for indoor positioning technology. Considering the complexity of indoor environment, this paper proposes a new positioning algorithm (N-CHAN) via the analysis of the error of arrival time positioning (TOA) and the channels of S-V model. It overcomes an obvious shortcoming that the accuracy of traditional CHAN algorithm effected by no-line-of-sight (NLOS). Finally, though MATLAB software simulation, we prove that N-CHAN’s superior performance in NLOS in the S-V channel model, which has a positioning accuracy of centimeter-level and can effectively eliminate the influence of NLOS error on positioning accuracy. Moreover, the N-CHAN can effectively improve the positioning accuracy of the system, especially in the conditions of larger NLOS error.

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Non-Line-of-Sight Error Mitigation in Wireless Communication Systems

Advanced Engineering Forum ◽

10.4028/www.scientific.net/aef.1.173 ◽

2011 ◽

Vol 1 ◽

pp. 173-177

Author(s):

Szu Lin Su ◽

Yi Wen Su ◽

Ho Nien Shou ◽

Chien Sheng Chen

Keyword(s):

Communication Systems ◽

Hybrid Methods ◽

Mobile Station ◽

Base Stations ◽

Superior Performance ◽

Line Of Sight ◽

Time Of Arrival ◽

Angle Of Arrival ◽

Error Statistics ◽

Non Line Of Sight

When there is non-line-of-sight (NLOS) path between the mobile station (MS) and base stations (BSs), it is possible to integrate many kinds of measurements to achieve more accurate measurements of the MS location. This paper proposed hybrid methods that utilize time of arrival (TOA) at five BSs and angle of arrival (AOA) information at the serving BS to determine the MS location in NLOS environments. The methods mitigate the NLOS effect simply by the weighted sum of the intersections between five TOA circles and the AOA line without requiring priori knowledge of NLOS error statistics. Simulation results show that the proposed methods always give superior performance than Taylor series algorithm (TSA) and the hybrid lines of position algorithm (HLOP).

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Grating Lobe-Free Beam Steering through Optical Phase Array Using Phase-Compensated Two Index-Mismatched Silicon Wires-Based Emitters

Applied Sciences ◽

10.3390/app10041225 ◽

2020 ◽

Vol 10 (4) ◽

pp. 1225

Author(s):

Rong-An Zhang ◽

Ting-Sheng Lin ◽

Wai-Ting Liu ◽

Shih-Hsiang Hsu ◽

Che-Chang Chang

Keyword(s):

Phase Shifter ◽

Beam Steering ◽

Thermal Control ◽

Phase Shifters ◽

Phase Array ◽

Optical Phase ◽

Grating Lobe ◽

Half Wavelength ◽

Beam Formation ◽

Free Beam

The beam formation can be treated as the diffraction pattern. A 1-D light detection and ranging beam steering could be derived through a phase shifter array using Rayleigh–Sommerfeld Diffraction, which is then utilized to demonstrate grating lobe-free beam steering from the optical phase array emitter with half-wavelength pitches. The half-wavelength pitch cannot demonstrate beam formation without any evanescent coupling blocking between emitters. Here, two index-mismatched silicon wires in the emitter array are proposed by the optical phase compensation through waveguide width adjustment, to avoid the complex and addressable thermal control on the phase shifters. Moreover, the same output optical waveguide mode needs to be further considered to demonstrate the grating lobe-free beam steering. In order to get the adiabatic connection between two different pitches between the phase shifter and emitter, an optical path equalization will also be applied.

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Flat telescope based on an all-dielectric metasurface doublet enabling polarization-controllable enhanced beam steering

Nanophotonics ◽

10.1515/nanoph-2021-0609 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Hongliang Li ◽

Changyi Zhou ◽

Woo-Bin Lee ◽

Duk-Yong Choi ◽

Sang-Shin Lee

Keyword(s):

Beam Steering ◽

Transverse Magnetic ◽

Light Polarization ◽

Two Dimensions ◽

Beam Deflection ◽

Magnification Factors ◽

Transverse Magnetic Polarization ◽

Scanning Range ◽

Hydrogenated Amorphous ◽

Dielectric Metasurface

Abstract A flat telescope (FTS), which incorporates an all-dielectric metasurface doublet (MD) based on hydrogenated amorphous silicon nanoposts, is proposed and demonstrated to achieve flexibly magnified angular beam steering that is sensitive to both light polarization and deflection direction. Specifically, for transverse-electric-polarized incident beams, the MD exhibits deflection magnification factors of +5 and +2, while for transverse magnetic polarization, the beam is steered in reverse to yield magnification factors of −5 and −2 in the horizontal and vertical directions, respectively. The proposed MD comprises cascaded metalenses, which can invoke polarization-selective transmission phases. The MD which emulates a set of convex and concave lenses renders positively increased beam deflection, whereas the case corresponding to a pair of convex lenses facilitates negatively amplified beam deflection. The essential phase profiles required for embodying the MD are efficiently extracted from its geometric lens counterpart. Furthermore, the implemented FTS, operating in the vicinity of a 1550 nm wavelength, can successfully enable enhanced beam steering by facilitating polarization-sensitive bidirectional deflection amplifications. The proposed FTS can be applied in the development of a miniaturized light detection and ranging system, where the beam scanning range can be effectively expanded in two dimensions.

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Results of fusion of LRI based attitude data in the attitude Kalman filter

10.5194/gstm2020-18 ◽

2020 ◽

Author(s):

Sujata Goswami ◽

Tamara Bandikova ◽

Dah-Ning Yuan ◽

Samuel Francis ◽

Bob Spero

Keyword(s):

Kalman Filter ◽

Gravity Field ◽

Beam Steering ◽

Line Of Sight ◽

Laser Ranging ◽

First Results ◽

Gravity Field Determination ◽

Gravity Recovery ◽

The Impact ◽

Technology Demonstrator

<p>Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) carries the Laser Ranging Interferometer (LRI) as a technology demonstrator that measures the inter-satellite range with nanometer precision. For the precise laser beam pointing, LRI uses the beam steering method where the fast steering mirror is actuated to correct for the misalignment between the incoming and outgoing laser beams. From the fast steering mirror commands, we can compute the inter-satellite pitch and yaw angles. These angles are provided as LSM1B product and represent spacecraft's relative orientation with respect to line-of-sight (LOS). The SCA1B data, which is computed by combining the data of three star cameras and IMU in the Kalman filter, represents the absolute orientation of the spacecrafts. Currently, this SCA1B product is used in the gravity field determination. &#160;</p> <p>Here we present first results of a new attitude product which is computed by the combination of fast steering mirror data with the star cameras and IMU in the attitude kalman filter.&#160; We also present the impact of this new combined attitude data on the gravity field solutions.</p>

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Experimental Evaluation of Multipath Mitigation in TDOA-Based Indoor Passive Localization System Using A Beam Steering Broadband Circular Polarization Antenna

Electronics ◽

10.3390/electronics7120362 ◽

2018 ◽

Vol 7 (12) ◽

pp. 362 ◽

Cited By ~ 1

Author(s):

Changjiang Su ◽

Yanqun Liu ◽

Leilei Liu ◽

Mei Yang ◽

Hongxin Zhao ◽

...

Keyword(s):

Circular Polarization ◽

Experimental Evaluation ◽

Multipath Propagation ◽

Beam Steering ◽

Line Of Sight ◽

Indoor Environments ◽

Rf Switch ◽

Multipath Mitigation ◽

Localization System ◽

Passive Localization

An experimental evaluation of multipath mitigation using a beam steering broadband circular polarization antenna (BSBCPA) in indoor passive localization system based on time differences of arrival (TDOA) is presented in this paper. The BSBCPA consists of a beam switch network, four identical hexagon patch elements and their respective feeding networks. By controlling the states of a radio frequency (RF) switch in the beam switch network, four steering circular polarization beams can be excited separately for azimuth omnidirectional coverage. Combining the spatial selectivity of steering beams and circular polarization in the BSBCPA, the positioning inaccuracy from indoor multipath propagation can be mitigated. In two different indoor environments with line of sight (LOS), complex multipath, when transmitting a 20 MHz bandwidth signal in WLAN, the 2D positioning mean error obtained is 0.7 m and 0.82 m, respectively. Compared with conventional omnidirectional linear polarization antenna (OLPA), the BSBCPA can at least improve positioning accuracy by 51%. The experimental results show that the proposed BSBCPA can significantly mitigate multipath propagation for TDOA-based indoor passive localization.

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