Defence Science Journal最新文献_第2页

Adaptive Technique for Contrast Enhancement of Leading Vehicle Tracks 车辆前导轨迹对比度增强自适应技术

4区工程技术

Defence Science Journal Pub Date : 2023-11-01 DOI: 10.14429/dsj.73.18765

Manoj Kumar Kalra, Ashutosh Trivedi, Sanjay Kumar Shukla

{"title":"Adaptive Technique for Contrast Enhancement of Leading Vehicle Tracks","authors":"Manoj Kumar Kalra, Ashutosh Trivedi, Sanjay Kumar Shukla","doi":"10.14429/dsj.73.18765","DOIUrl":"https://doi.org/10.14429/dsj.73.18765","url":null,"abstract":"During movement in various unpaved terrain conditions, the track impressions left over by the leading vehicles provide guiding and safe routes in the area. The delineation of these tracks captured by the images can extend immense support for guidance in real time. These tracks that look like edges in coarse-resolution images take the shape of elongated areas in fine-resolution images. In such a scenario, the high pass and edge detection filters give limited information to delineate these tracks passing through different surroundings. However, the distinct texture of these tracks assists in the delineation of these tracks from their surroundings. Gray level co-occurrence matrix (GLCM) representing the spatial relation of pixels is employed here to define the texture. The authors investigated the influence of different resolutions on the distinguishability of these tracks. The study revealed that texture plays an increasing role in distinguishing objects as the image resolution improves. The texture analysis extended to investigate the track impressions left over by the leading vehicle brings out an ample scope in delineating these tracks. The measures could improve the track contrast even better than conventional techniques. To select the most optimal contrast enhancement measure in a given scenario, authors proposed a quantified measure of track index. An investigation is made on the difference-based track index (TI) representing the mean contrast value of the track vis-à-vis off-track areas. The results show an increase in the quantified contrast from 7.83 per cent to 29.06 per cent. The proposed technique highlights the image with the highest track contrast in a given scenario. The study can lead to onboard decision-making for the rut following vehicles moving in low-contrast terrain.","PeriodicalId":11043,"journal":{"name":"Defence Science Journal","volume":"91 1-2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135614622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

GPS Receiver Simplification for Low cost Applications and Multipath Mitigation Analysis on SDR based Re configurable Software Receiver 面向低成本应用的GPS接收机简化及基于SDR可重构软件接收机的多径抑制分析

4区工程技术

Defence Science Journal Pub Date : 2023-11-01 DOI: 10.14429/dsj.73.19033

B. Sathish Nayak, K.Krishna Naik, Odelu Ojjela, Surendra Pal

{"title":"GPS Receiver Simplification for Low cost Applications and Multipath Mitigation Analysis on SDR based Re configurable Software Receiver","authors":"B. Sathish Nayak, K.Krishna Naik, Odelu Ojjela, Surendra Pal","doi":"10.14429/dsj.73.19033","DOIUrl":"https://doi.org/10.14429/dsj.73.19033","url":null,"abstract":"Many modern position-based applications rely heavily on the Global Navigation Satellite System (GNSS). Most applications require precise position data obtained through sophisticated hardware with a high computational capacity in the receiver. Some cost-effective applications may not require precise position data and require less complex signal processing. The use of efficient hardware and signal processing techniques to reduce the overall cost of a GNSS receiver is an active research topic. This paper considers Global Positioning System (GPS) constellation and proposes two factors to reduce the receiver complexity: sampling frequency and the number of tracking channels. A Keysight GNSS signal generator to record GPS signals, a Software Defined Radio board and a software-based GPS receiver are used in the experimentation. The sampling frequencies are 40, 20, 10 and 5 MHz considered, and tracking channels are reduced from 12 to 6 and then 4. The increase of error in the receiver position with 6 and 4 satellites is considerably small, but the number of tracking channels and signal processing requirements are reduced considerably. The GPS signals are affected by many errors; one of the significant sources of error is multipath propagation. Three distinct GPS multipath scenarios are generated for four satellite signal combinations with the GNSS simulator for the receiver performance analysis. Three multipath mitigation techniques, namely Early Minus Late (EML), Narrow correlator (NC) and strobe correlator (SC) methods, are considered because of their simple structure and fewer signal processing requirements. The error reductions of three multipath scenarios are compared, and the SC method performs better in all three multipath scenarios.","PeriodicalId":11043,"journal":{"name":"Defence Science Journal","volume":"173 5-6","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135614754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Analysis of Pilot Distance Estimation in Different Lighting and Visibility Conditions 不同光照和能见度条件下飞行员距离估计分析

4区工程技术

Defence Science Journal Pub Date : 2023-11-01 DOI: 10.14429/dsj.73.19080

İsmail Gevrek, Murat Akın, Metin Guru

引用次数: 0

Closed Loop Vector Formulation in Eulers Complex Numbers for Multi Loop Planar Mechanisms With N bars A Novel Modeling Approach and Algorithm 多环平面机构的欧拉复数闭环矢量形式一种新的建模方法和算法

4区工程技术

Defence Science Journal Pub Date : 2023-11-01 DOI: 10.14429/dsj.73.18941

Rahul V M, Sandesh Bhaktha, Gangadharan K.V.

{"title":"Closed Loop Vector Formulation in Eulers Complex Numbers for Multi Loop Planar Mechanisms With N bars A Novel Modeling Approach and Algorithm","authors":"Rahul V M, Sandesh Bhaktha, Gangadharan K.V.","doi":"10.14429/dsj.73.18941","DOIUrl":"https://doi.org/10.14429/dsj.73.18941","url":null,"abstract":"This paper presents a novel iterative algorithm incorporated in a user-friendly GUI for modeling the kinematics of multiple looped N-bar closed-loop mechanisms. Past research works have used custom coding or expensive commercial software to analyze the mechanisms of specific applications. The proposed algorithm focuses on kinematics and offers a quick, easy-to-use, cost-effective solution to analyze a wide range of generic mechanisms, reducing the need for custom coding and lowering computational costs. The algorithm employs algebraic equations, such as solving complex closed-loop vector equations using the Euler form of complex numbers, to simulate and derive the unknowns necessary to characterise any generic closed-loop mechanism. The Python code implemented in the algorithm adapts to various scenarios by utilising available information on the position, velocity, and acceleration variables of the mechanisms. The simulation tool can display real-time color contour plots (RGB color scale) for linear and angular velocities and accelerations, simulate mechanisms with multiple loops and switch configurations, and find inverse mechanisms. The approach for solving multiple loop problems and the algorithm utilized to solve the configurations, methods, equations used and GUI features implementation are all described in this study. The case study considered for a four-bar mechanism indicates a strong agreement between the results obtained from the proposed kinematics-based simulator and ANSYS software. These results demonstrate the simulator’s effectiveness in providing low-cost and user-friendly simulation results for various generic mechanisms involving multiple interconnected loops.","PeriodicalId":11043,"journal":{"name":"Defence Science Journal","volume":"106 1-2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135614904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Process Optimization and Design of an Automation Controller for a Multidisciplinary Combat Engineering System 多学科作战工程系统过程优化与自动控制器设计

4区工程技术

Defence Science Journal Pub Date : 2023-09-01 DOI: 10.14429/dsj.73.18731

Moiz Hatim Chasmai, Arun Kumar Barde, Chandrakant Supare, Gagandeep Purohit, Abhijit Kamble, Sandeep S.

引用次数: 0

Design of a Low Profile Archimedean Spiral Antenna using Compact Defected Ground Structure as a Reflector 采用紧凑缺陷接地结构作为反射面的低轮廓阿基米德螺旋天线设计

4区工程技术

Defence Science Journal Pub Date : 2023-08-31 DOI: 10.14429/dsj.73.17751

Sukhdas Ahirwar, Amara Prakasa Rao, Mada Chakravarthy

{"title":"Design of a Low Profile Archimedean Spiral Antenna using Compact Defected Ground Structure as a Reflector","authors":"Sukhdas Ahirwar, Amara Prakasa Rao, Mada Chakravarthy","doi":"10.14429/dsj.73.17751","DOIUrl":"https://doi.org/10.14429/dsj.73.17751","url":null,"abstract":"In this paper, design and realisation of a low profile Archimedean spiral antenna is presented. The low profile Archimedean spiral antenna is printed on a substrate and backed by a reflector consisting of DGS. The DGS unit cell consists of a parallel combination of meander line inductors and inter-digital capacitors. This, DGS is one of the forms of electromagnetic band gap (EBG) structures providing electromagnetic band gap characteristics. It is used as a reflector with spiral antenna to achieve unidirectional radiation properties and a low profile of antenna. A modified version of uniplanar EBG cell is used as a DGS cell. This cell is used for configuration of the DGS ground plane. This ground plane is evaluated for its electrical characteristics and used as a reflector for the spiral antenna. Archimedean Spiral antenna is designed and simulated in the frequency band of 1-6GHz with DGS as a reflector. The antenna characteristics are studied for physical parameters of the antenna. These parameters are optimized for better electrical characteristics. The performance of the proposed antenna is also compared with conventional metallic (PEC) reflectors. Simulated results of an antenna are validated by measurement. Antenna height reduction of 60% is achieved compared to conventional cavity-backed spiral antennas.","PeriodicalId":11043,"journal":{"name":"Defence Science Journal","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136036888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Analysis of the Effect of Circular Ring Baffles in Suppressor on Flow Field and Far Field Noise Levels at 9 mm Semi Automatic Pistol 消声器环形挡板对9mm半自动手枪流场和远场噪声水平的影响分析

4区工程技术

Defence Science Journal Pub Date : 2023-08-31 DOI: 10.14429/dsj.73.18528

Onur Gurdamar, Seyda Ozbektas, Bilal Sungur

{"title":"Analysis of the Effect of Circular Ring Baffles in Suppressor on Flow Field and Far Field Noise Levels at 9 mm Semi Automatic Pistol","authors":"Onur Gurdamar, Seyda Ozbektas, Bilal Sungur","doi":"10.14429/dsj.73.18528","DOIUrl":"https://doi.org/10.14429/dsj.73.18528","url":null,"abstract":"A firearm generates complex phenomena in muzzle flow and modelling the flow field around the projectile has great importance on high-intensity noise prediction. The negative effects of noise can be reduced using a suppressor which can be internally or externally attached to the barrel of a firearm. The purpose of this paper is to numerically and experimentally investigate the effect of the number and distance of circular ring baffles in the suppressor on the flow field and far field noise levels. Calculations were carried out in two-dimensional, axisymmetric, transient conditions and Ffowcs Williams and Hawkings acoustic analogy (FW-H) equations were solved to predict the far field noise. Nine cases including a gun without a suppressor, a suppressor without baffles, one, three, and five baffles which were placed at 20 mm intervals from the suppressor inlet, and one, three, five, seven, and nine baffles which were placed with equal intervals in the suppressor were simulated and compared; generations of noise during the shooting process were analyzed. The results showed that in the case without a suppressor, the peak sound pressure level was 156.1 dB at a 2.5 m distance, while this value decreased by nearly 7.6% in the case of the suppressor with seven baffles which has an average value of 144.2 dB. The results obtained here may provide a beneficial reference for predicting the muzzle noise and optimizing the number of baffles in the suppressor for small caliber gun systems.","PeriodicalId":11043,"journal":{"name":"Defence Science Journal","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136036891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

APSO based automated planning in Constructive Simulation 构建仿真中基于APSO的自动化规划

4区工程技术

Defence Science Journal Pub Date : 2023-08-31 DOI: 10.14429/dsj.73.18497

Sanjay Bisht, S.B. Taneja, Vinita Jindal, Punam Bedi

引用次数: 1

Design Validation and Reliability Assurance of Electronic Systems Using the Next Generation RGT Models 基于下一代RGT模型的电子系统设计验证与可靠性保证

4区工程技术

Defence Science Journal Pub Date : 2023-08-31 DOI: 10.14429/dsj.73.18798

Mustaq Basha, Nilesh R. Ware

{"title":"Design Validation and Reliability Assurance of Electronic Systems Using the Next Generation RGT Models","authors":"Mustaq Basha, Nilesh R. Ware","doi":"10.14429/dsj.73.18798","DOIUrl":"https://doi.org/10.14429/dsj.73.18798","url":null,"abstract":"Arrhenius Accelerated Growth Model (AAGT) is the next generation accelerated testing models used for design validation and reliability assurance of electronics systems. These models are used in design and manufacturing phases towards reliability enhancement of the system respectively. AAGT Models uses Highly Accelerated Stresses for screening of the components towards uncovering Compared to traditional qualification test methods, design flaws, latent defects, component selection problems, and manufacturing flaws can be detected fast. The procedure includes thermal dwells and quick temperature changes while subjecting the test unit to increasing degrees of stress. Dynamic stresses (Pseudo-Random Vibration covering all 6DOF systems) and a combination of thermal and dynamic PSD stresses towards quickly precipitating inherent/hidden defects quickly. These Accelerated models used to qualify modern active array radar modules like Transmit Receive Modules (TRMs) which will be in large numbers and It will be difficult and time-consuming to filter these modules individually using the traditional way. To increase the quality and dependability of electronic devices, much accelerated life tests have been extensively adopted. However, extremely accelerated life tests may only be used as a qualitative approach to assess a product's dependability; they cannot be used to quantify a product's reliability, such as MTBF/MTTF. Consequently, in order to efficiently assess the level of product reliability while improving product reliability in a timely manner. HALT/HASS uses Arrhenius Accelerated Growth Model that is an effective technique used for screening of the module with in short period. This paper discuss in detail with a case study on active array modules deliberating about the test methodology, challenges faced during Using Arrhenius accelerated test models, rapid testing and assessment of these Four channel TRMs used for airborne Fire Control Radar for combat operations.","PeriodicalId":11043,"journal":{"name":"Defence Science Journal","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136036892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Effect of Twin Island Configuration on Airwake Aerodynamics over Generic Aircraft Carrier using CFD 基于CFD的双岛结构对通用航母尾流气动特性的影响

4区工程技术

Defence Science Journal Pub Date : 2023-08-31 DOI: 10.14429/dsj.73.18617

Ankit Nehra, Vijayakumar Rajagopalan

{"title":"Effect of Twin Island Configuration on Airwake Aerodynamics over Generic Aircraft Carrier using CFD","authors":"Ankit Nehra, Vijayakumar Rajagopalan","doi":"10.14429/dsj.73.18617","DOIUrl":"https://doi.org/10.14429/dsj.73.18617","url":null,"abstract":"The technological advancements have led to the evolution of numerous concepts in an aircraft carrier’s topdeck design, the twin island concept being the latest entrant. An aircraft carrier’s bluff body geometry presents many challenges to the pilot, landing on deck being the most critical. The present study aims to undertake a computational investigation of the aerodynamic analysis of a Twin Island GAC (Generic Aircraft Carrier) conceptualized vis- à-vis its base variant. The flow over the twin island GAC flight deck and downstream is analysed using various transverse planes perpendicular to the flow direction as detailed in the paper. Subsequently, a parametric study was undertaken for understanding the effects of longitudinal translations of the two islands with respect to the baseline GAC position. The results depict the advantage of certain variants of twin islands over a single island, and ~68 % reduction in turbulence is achieved along the glideslope by one of the variations which could aid in reducing pilot workload. The data can act as a catalyst for utilization and incorporation in future floating platform designs and further studies in this field.","PeriodicalId":11043,"journal":{"name":"Defence Science Journal","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136037036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0