scholarly journals Simulative Investigation of FMCW Based Optical Photonic Radar And Its Different Configurations

2021 ◽  
Author(s):  
Abhishek Sharma ◽  
Jyoteesh Malhotra
Keyword(s):  
Thermal Noise ◽  
Continuous Wave ◽  
Direct Detection ◽  
Smart Cities ◽  
Autonomous Vehicle ◽  
Coherent Detection ◽  
Target Range ◽  
Detection Scheme ◽  
The Cost ◽  
Detection Schemes

Abstract Intelligent transportation is becoming integral part of future smart cities where driverless operations may provide hassle free conveyance. Photonic radar technology is one such contender to deliver attractive applications in autonomous vehicle sector. In this paper we have discussed the basic principle of frequency modulated continuous wave (FMCW) photonic radar and their possible advantages. Further the basic detection schemes that is direct detection and coherent detection is explained mathematically as well as numerical simulations to understand workings is also carried out. The obtained results concludes that direct detection scheme provides minimal complexity in its architecture and is sensitive to received signal strength at the cost of thermal noise and poor sensitivity. On the other hand, coherent detection offers higher target range estimation as well as velocity measurement at the expense of increased system complexity.

scholarly journals CW Direct Detection Lidar with a Large Dynamic Range of Wind Speed Sensing in a Remote and Spatially Confined Volume

2021 ◽  
Vol 13 (18) ◽  
pp. 3716
Author(s):  
Lichun Meng ◽  
Christian Pedersen ◽  
Peter John Rodrigo
Keyword(s):  
Wind Speed ◽  
High Speed ◽  
Continuous Wave ◽  
Dynamic Range ◽  
Weighting Function ◽  
Direct Detection ◽  
Coherent Detection ◽  
Axial Profile ◽  
Update Rate ◽  
Wind Lidar

A novel continuous-wave (CW) direct detection lidar (DDL) is demonstrated to be capable of wind speed measurement 40 m away with an update rate of 4 Hz using a fiber-based scanning Fabry–Perot interferometer as an optical frequency discriminator. The proposed CW DDL has a large dynamic wind speed range with no sign ambiguity and its sensitivity is assessed by comparing its performance with that of a CW coherent detection lidar (CDL) in a side-by-side wind measurement. A theoretical model of the spatial weighting function of the fiber-based CW DDL is also presented and validated experimentally. This work shows that the CW DDL has a spatially confined measurement volume with a Lorentzian axial profile similar to that of a CW CDL. The proposed DDL has potential use in various applications in which requirements such as high-speed wind sensing and directional discrimination are not met by state-of-the-art Doppler wind lidar systems.

scholarly journals A Cost-Effective Photonic Radar Under Adverse Weather Conditions for Autonomous Vehicles by Incorporating a Frequency-Modulated Direct Detection Scheme

2021 ◽  
Vol 9 ◽  
Author(s):  
Abhishek Sharma ◽  
Sushank Chaudhary ◽  
Jyoteesh Malhotra ◽  
Muhammad Saadi ◽  
Sattam Al Otaibi ◽  
...  
Keyword(s):  
Autonomous Vehicles ◽  
Direct Detection ◽  
Signal To Noise Ratio ◽  
Autonomous Vehicle ◽  
Cost Effective ◽  
Weather Conditions ◽  
Atmospheric Conditions ◽  
Detection Scheme ◽  
Available Bandwidth ◽  
Adverse Weather

In recent years, there have been plenty of demands and growth in the autonomous vehicle industry, and thus, challenges of designing highly efficient photonic radars that can detect and range any target with the resolution of a few centimeters have been encountered. The existing radar technology is unable to meet such requirements due to limitations on available bandwidth. Another issue is to consider strong attenuation while working under diverse atmospheric conditions at higher frequencies. The proposed model of photonic radar is developed considering these requirements and challenges using the frequency-modulated direct detection technique and considering a free-space range of 750 m. The result depicts improved range detection in terms of received power and an acceptable signal-to-noise ratio and range under adverse climatic situations.

APPROACH TO DETERMINING THE VALUE OF THE DYNAMIC RANGE OF AN OPTICAL RECEIVER THAT IMPLEMENTS DIRECT AND HETERODYNE DETECTION METHODS

2020 ◽  
pp. 86-91
Author(s):  
А.Ю. Козирацкий ◽  
А.И. Гревцев ◽  
Р.И. Буров
Keyword(s):  
Dynamic Range ◽  
Direct Detection ◽  
Decisive Role ◽  
Comparative Assessment ◽  
Optical Receiver ◽  
Heterodyne Detection ◽  
Detection Methods ◽  
Detection Scheme ◽  
Value Analysis ◽  
Detection Schemes

Рассматриваются вопросы, связанные с определением возможностей использования фотодетекторов в различных схемах детектирования при приеме сигналов с изменяющейся амплитудой. Определены особенности влияния реализуемых на практике схем детектирования на величину динамического диапазона фотодетектора и потенциально достижимую чувствительность. Разработан подход, позволяющий провести сравнительную оценку изменения величины динамического диапазона в зависимости от реализуемой схемы оптического приемника. Показано, что в отличие от схемы прямого детектирования, где величина динамического диапазона напрямую определяется свойствами самого фотодетектора, при гетеродинном детектировании основную роль в определении указанной величины играет уровень опорного колебания. Анализ полученных результатов показывает, что адаптивное управление величиной опорного колебания при переходе к схеме гетеродинного детектирования с сохранением типа фотодетектора позволяет не только существенно расширить диапазон изменения амплитуды принимаемых сигналов и максимизировать величину динамического диапазона, но и реализовать потенциально достижимую чувствительность, величина которой определяется шумовыми свойствами самого фотодетектора. Конкретизация типа рассматриваемых фотодетекторов позволила ограничиться рассмотрением только теплового и дробового шумов. Определение величины динамического диапазона для других типов фотодетекторов в рамках данного подхода возможно с учетом присущих им шумовых свойств Here we consider issues related to determining the possibilities of using photodetectors in various detection schemes when receiving signals with varying amplitudes. We determined the features of the influence of practical detection schemes on the value of the dynamic range of the photodetector and the potentially achievable sensitivity. We developed an approach that allows for a comparative assessment of changes in the dynamic range depending on the implemented optical receiver scheme. We show that in contrast to the direct detection scheme, where the value of the dynamic range is directly determined by the properties of the photodetector itself, in the case of heterodyne detection, the level of the reference oscillation plays a decisive role in determining this value. Analysis of the obtained results shows that adaptive control of the reference oscillation value when switching to the heterodyne detection scheme with the preservation of the photodetector type allows us not only to significantly expand the range of changes in the amplitude of the received signals and maximize the dynamic range but also to realize a potentially achievable sensitivity, the value of which is determined by the noise properties of the photodetector itself

scholarly journals Range-speed mapping and target-classification measurements of automotive targets using photonic-radar

2020 ◽  
Vol 52 (10) ◽  
Author(s):  
Vishal Sharma ◽  
Sergey Sergeyev ◽  
Love Kumar ◽  
Hani J. Kbashi
Keyword(s):  
Autonomous Vehicles ◽  
Continuous Wave ◽  
Target Identification ◽  
Autonomous Vehicle ◽  
Vertical Axis ◽  
Input Power ◽  
Target Range ◽  
Target Velocity ◽  
Microwave Radar ◽  
Wave Radar

Abstract The frequency-modulated continuous-wave radar is an ideal choice for autonomous vehicle and surveillance-related industries due to its ability to measure the relative target-velocity, target-range, and target-characterization. Unlike conventional microwave radar systems, the photonic radar has the potential to offer wider bandwidth to attain high range-resolution at low input power requirements. Subsequently, a frequency-modulated continuous-wave photonic-radar is developed to measure the target-range and velocity of the automotive mobile targets concurrently with acceptable rang resolution keeping in mind the needs of the state-of-the-art autonomous vehicle industry. Furthermore, the target-identification is also an important parameter to be measured to enable the futuristic autonomous vehicles for the recognition of the objects along with their dimensions. Therefore, the reported work is extended to characterize the target-objects by measuring the specular-reflectance, diffuse-reflectance, the ratio of horizontal-axis to vertical-axis, refractive index constants of the targets using the bidirectional reflectance distribution function. Furthermore, the reflectance properties of the target-objects are also measured with different operating wavelengths at different incident angles to assess the influence of the operating wavelength and the angle at which the radar-pulses incident on the surface of the targets. Moreover, to validate the performance of the demonstrated work, a comparison is also presented in distinction with the conventional microwave FMCW-RADAR.

scholarly journals Nondestructive Internal Defect Detection Using a CW–THz Imaging System in XLPE for Power Cable Insulation

2020 ◽  
Vol 10 (6) ◽  
pp. 2055 ◽  
Author(s):  
In-Sung Lee ◽  
Joong Wook Lee
Keyword(s):  
Nondestructive Testing ◽  
Continuous Wave ◽  
Imaging System ◽  
Electrical Power ◽  
Coherent Detection ◽  
Power Cable ◽  
Thz Imaging ◽  
Cable Insulation ◽  
Detection Scheme ◽  
Thz Waves

The demand for internal nondestructive testing and inspection techniques is rapidly increasing. Using a continuous wave (CW) terahertz (THz) imaging system, we demonstrate that the internal defects in cross-linked polyethylene (XLPE) plates for power cable insulation can be detected. In a coherent detection scheme based on photomixers, which serve as the THz emitters and receivers, the change of phase occurring with the defects inside the XLPE plates is distinctly measured by the change in the amplitude of the transmitted THz waves. According to the two-dimensional images of THz waves transmitted through the XLPE plates, defects of up to 0.5 mm size located inside the XLPE plates can be detected by the internal nondestructive examination method based on CW–THz waves. This technique will be useful for internal nondestructive testing and inspection of insulation materials that require high resolution in various industries, including the automobiles, electronics, and electrical power industries.

ARFIS: Adaptive-Receiver-Based Fuzzy Inference System for Diffusion- Based Molecular Communications

2020 ◽  
Vol 16 (2) ◽  
pp. 280-289
Author(s):  
Ghalib H. Alshammri ◽  
Walid K. M. Ahmed ◽  
Victor B. Lawrence
Keyword(s):  
Fuzzy Inference System ◽  
Fuzzy Inference ◽  
Detection Threshold ◽  
Learning Rule ◽  
Optimal Number ◽  
Molecular Communication ◽  
Inference System ◽  
Detection Scheme ◽  
Adaptive Receiver ◽  
Detection Schemes

Background: The architecture and sequential learning rule-based underlying ARFIS (adaptive-receiver-based fuzzy inference system) are proposed to estimate and predict the adaptive threshold-based detection scheme for diffusion-based molecular communication (DMC). Method: The proposed system forwards an estimate of the received bits based on the current molecular cumulative concentration, which is derived using sequential training-based principle with weight and bias and an input-output mapping based on both human knowledge in the form of fuzzy IFTHEN rules. The ARFIS architecture is employed to model nonlinear molecular communication to predict the received bits over time series. Result: This procedure is suitable for binary On-OFF-Keying (Book signaling), where the receiver bio-nanomachine (Rx Bio-NM) adapts the 1/0-bit detection threshold based on all previous received molecular cumulative concentrations to alleviate the inter-symbol interference (ISI) problem and reception noise. Conclusion: Theoretical and simulation results show the improvement in diffusion-based molecular throughput and the optimal number of molecules in transmission. Furthermore, the performance evaluation in various noisy channel sources shows promising improvement in the un-coded bit error rate (BER) compared with other threshold-based detection schemes in the literature.

scholarly journals Accurate Power-Efficient Format-Scalable Multi-Parallel Optical Digital-to-Analogue Conversion

Photonics ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 38
Author(s):  
Moshe Nazarathy ◽  
Ioannis Tomkos
Keyword(s):  
Energy Efficiency ◽  
Direct Detection ◽  
Coherent Detection ◽  
Performance Limits ◽  
Optical Modulators ◽  
Analog To Digital ◽  
Power Efficient ◽  
Optical Signals ◽  
Digital To Analog Converters ◽  
Optical Analog

In optical transmitters generating multi-level constellations, optical modulators are preceded by Electronic Digital-to-Analog-Converters (eDAC). It is advantageous to use eDAC-free Optical Analog to Digital Converters (oDAC) to directly convert digital bitstreams into multilevel PAM/QAM optical signals. State-of-the-art oDACs are based on Segmented Mach-Zehnder-Modulators (SEMZM) using multiple modulation segments strung along the MZM waveguides to serially accumulate binary-modulated optical phases. Here we aim to assess performance limits of the Serial oDACs (SEMZM) and introduce an alternative improved Multi-Parallel oDAC (MPoDAC) architecture, in particular based on arraying multiple binary-driven MZMs in parallel: Multi-parallel MZM (MPMZM) oDAC. We develop generic methodologies of oDAC specification and optimization encompassing both SEMZM and MPMZM options in Direct-Detection (DD) and Coherent-Detection (COH) implementations. We quantify and compare intrinsic performance limits of the various serial/parallel DD/COH subclasses for general constellation orders, comparing with the scant prior-work on the multi-parallel option. A key finding: COH-MPMZM is the only class synthesizing ‘perfect’ (equi-spaced max-full-scale) constellations while maximizing energy-efficiency-SEMZM/MPMZM for DD are less accurate when maximal energy-efficiency is required. In particular, we introduce multiple variants of PAM4|8 DD and QAM16|64 COH MPMZMs, working out their accuracy vs. energy-efficiency-and-complexity tradeoffs, establishing their format-reconfigurability (format-flexible switching of constellation order and/or DD/COH).

scholarly journals Object Detection, Distributed Cloud Computing and Parallelization Techniques for Autonomous Driving Systems

2021 ◽  
Vol 11 (7) ◽  
pp. 2925
Author(s):  
Edgar Cortés Gallardo Medina ◽  
Victor Miguel Velazquez Espitia ◽  
Daniela Chípuli Silva ◽  
Sebastián Fernández Ruiz de las Cuevas ◽  
Marco Palacios Hirata ◽  
...  
Keyword(s):  
Neural Networks ◽  
Cloud Computing ◽  
Path Planning ◽  
Object Detection ◽  
Short Term Memory ◽  
Smart Cities ◽  
Autonomous Vehicle ◽  
Computational Time ◽  
End To End ◽  
On The Road

Autonomous vehicles are increasingly becoming a necessary trend towards building the smart cities of the future. Numerous proposals have been presented in recent years to tackle particular aspects of the working pipeline towards creating a functional end-to-end system, such as object detection, tracking, path planning, sentiment or intent detection, amongst others. Nevertheless, few efforts have been made to systematically compile all of these systems into a single proposal that also considers the real challenges these systems will have on the road, such as real-time computation, hardware capabilities, etc. This paper reviews the latest techniques towards creating our own end-to-end autonomous vehicle system, considering the state-of-the-art methods on object detection, and the possible incorporation of distributed systems and parallelization to deploy these methods. Our findings show that while techniques such as convolutional neural networks, recurrent neural networks, and long short-term memory can effectively handle the initial detection and path planning tasks, more efforts are required to implement cloud computing to reduce the computational time that these methods demand. Additionally, we have mapped different strategies to handle the parallelization task, both within and between the networks.

scholarly journals Terahertz quantum sensing

2020 ◽  
Vol 6 (11) ◽  
pp. eaaz8065 ◽  
Author(s):  
Mirco Kutas ◽  
Björn Haase ◽  
Patricia Bickert ◽  
Felix Riexinger ◽  
Daniel Molter ◽  
...  
Keyword(s):  
Layer Thickness ◽  
Region Of Interest ◽  
Coherent Detection ◽  
Semiconductor Detectors ◽  
Terahertz Frequency ◽  
Sensing Applications ◽  
Highly Sensitive ◽  
Quantum Sensing ◽  
Thickness Measurements ◽  
Detection Schemes

Quantum sensing is highly attractive for accessing spectral regions in which the detection of photons is technically challenging: Sample information is gained in the spectral region of interest and transferred via biphoton correlations into another spectral range, for which highly sensitive detectors are available. This is especially beneficial for terahertz radiation, where no semiconductor detectors are available and coherent detection schemes or cryogenically cooled bolometers have to be used. Here, we report on the first demonstration of quantum sensing in the terahertz frequency range in which the terahertz photons interact with a sample in free space and information about the sample thickness is obtained by the detection of visible photons. As a first demonstration, we show layer thickness measurements with terahertz photons based on biphoton interference. As nondestructive layer thickness measurements are of high industrial relevance, our experiments might be seen as a first step toward industrial quantum sensing applications.

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