2015 Fourth International Conference on Aerospace Science and Engineering (ICASE)最新文献

{"title":"Improvement of gain in dual fed X band isoflux Choke horn antenna for use in LEO satellite mission","authors":"Wasim Nawaz, A. S. Shafaat Ali","doi":"10.1109/ICASE.2015.7489517","DOIUrl":"https://doi.org/10.1109/ICASE.2015.7489517","url":null,"abstract":"For high image data rate transmission from LEO satellites in X band frequency range, horn antenna is generally used for this purpose. Due to high data rate transmission, there is a requirement of high EIRP from space segment. This EIRP requirement is met by using antenna of high gain as much as possible with wide beamwidth due to the limitation of RF power transmission onboard the satellite. Recently, Isoflux choke horn antennas are been used in LEO satellite programs which provides an added advantage of maintaining a near to constant signal to noise ratio over the complete communication path. Isoflux Choke horn antenna used in commercial & space applications have uniform length of choke rings which provides near to Isoflux pattern. In this paper, gain enhancement has been done by introducing nonlinear size of choke rings which results an additional link margin value. Improvement of 1.5 dB gain is achieved by introducing this concept. Circular polarization is achieved using dual fed mechanism. The optimized design shows low side lobe and back lobe levels with excellent cross polarization achieved, which ensures better polarization purity and that only required polarization signal is received at the receiving end. Prototype measurement results are in close conformance with the simulated results. Measured Isoflux pattern has a gain of > 7 dB over horizon to horizon earth coverage with axial ratio <; 3 dB. VSWR value in the desired X band frequency range is <; 2.","PeriodicalId":223483,"journal":{"name":"2015 Fourth International Conference on Aerospace Science and Engineering (ICASE)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123069510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fingerprint enhancement over the past few years","authors":"A. R. Baig, A. Baig, K. Khurshid","doi":"10.1109/ICASE.2015.7489512","DOIUrl":"https://doi.org/10.1109/ICASE.2015.7489512","url":null,"abstract":"This paper furnishes a review of the research trends and the methodologies adopted and adapted for enhancing fingerprints in the recent past. Our area of focus is primarily latent fingerprints. Previously, the studies on fingerprint enhancement segregate the techniques mostly in spatial and frequency domains. But, in our paper we have broadly divided the enhancement technics into Gabor based and non-Gabor based (variations of conventional Gabor and others).","PeriodicalId":223483,"journal":{"name":"2015 Fourth International Conference on Aerospace Science and Engineering (ICASE)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121029183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Track fusion of legacy radars using weighted averages","authors":"S. Arif, Sohail Ahmed, S. Akhtar, Irfan Aziz","doi":"10.1109/ICASE.2015.7489501","DOIUrl":"https://doi.org/10.1109/ICASE.2015.7489501","url":null,"abstract":"In air defense systems, multiple radars with overlapping area of coverage are deployed for surveillance and tracking of aircraft. In such a situation, multiple tracks on the same target may appear. The problem of determining whether two tracks have originated from the same target is termed as Track-to-Track Association (T2TA). This process is followed by a Track-to-Track Fusion (T2TF) process which is done to fuse the tracks of multiple radars. Many multiple radar systems employ centralized T2TA and T2TF which takes place in a fusion center while the radars and their trackers are remotely located from the fusion center. Ideally, the radar trackers must supply target state estimates as well as the covariance and cross-covariance to the fusion center for optimal T2TA and T2TF. However, in case of legacy radars, only the target state estimates are provided to the fusion center. We propose a suboptimal but simple-to-implement technique based on weighted averages for T2TA and T2TF of legacy tracks. In the proposed technique, weighted averages are based on the reliability of the radar, track quality and deviation of target trajectory estimate from its smoothed value.","PeriodicalId":223483,"journal":{"name":"2015 Fourth International Conference on Aerospace Science and Engineering (ICASE)","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114535516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Remote sensing of ocean, ice and land surfaces using bistatically reflected GNSS signals from low Earth orbit","authors":"Jabir Shabbir Malik, U. I. Bhatti","doi":"10.1109/ICASE.2015.7489519","DOIUrl":"https://doi.org/10.1109/ICASE.2015.7489519","url":null,"abstract":"The reflection of (Global Navigation Satellites) signals from the Earth's surface has progressed to demonstrate a practical linkage of measurements to geophysical description of ocean, ice and land areas. Since launch of the small constellation, it has been successfully used to target and detect specular reflections of GPS signals after scattering from the Earth's oceans, ice sheets and land surfaces. All data sets have exposed reflected signals, including signals reflected off the ocean under different ocean conditions. This reveals that GNSS Reflectometry is a suitable future technology for space based Earth remote sensing, even when deployed on the UK DMC low Earth orbiting satellite system. This paper presents a summary of the signals collected from over the ocean, and an examination of the signal relationship to the ocean wind and wave conditions is presented. The initial results from ice and land surfaces reflection analysis are also described.","PeriodicalId":223483,"journal":{"name":"2015 Fourth International Conference on Aerospace Science and Engineering (ICASE)","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133471278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improving the detection and estimation processes of acquisition module in Global Navigation Satellite Systems (GNSS)","authors":"Maria Mehmood","doi":"10.1109/ICASE.2015.7489520","DOIUrl":"https://doi.org/10.1109/ICASE.2015.7489520","url":null,"abstract":"Acquisition is the first task of any receiver used for positioning and navigation applications. The acquisition block of a GNSS receiver not only decides which satellite is present or not but also determines the carrier frequency and code phase of the satellite, if present. Therefore acquisition involves both detection and estimation processes, and it follows that the acquisition technique can be affected by factors involved in either detection or estimation processes. This paper discusses various factors that can be manipulated to improve the performance of the processes involved in acquisition. Digitized data at intermediate frequency (IF) was collected with a front end logger and was input to the software receiver. The software receiver implements different acquisition schemes by varying factors such as length of data, correlation time and number of blocks used for non-coherent integration. Factors related to the signal such as sampling frequency, IF and signal strength were also changed to analyze different acquisition schemes. The analysis provides a better understanding of the acquisition process and eventually leads to accurate and reliable positioning.","PeriodicalId":223483,"journal":{"name":"2015 Fourth International Conference on Aerospace Science and Engineering (ICASE)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124319497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of additive manufacturing techniques for fabrication of propellers for SUAVs","authors":"Shaheryar A. Khan, Bilal A. Siddiqui, M. Fahad","doi":"10.1109/ICASE.2015.7489510","DOIUrl":"https://doi.org/10.1109/ICASE.2015.7489510","url":null,"abstract":"Small unmanned aerial vehicles (SUAVs) find wide-ranging civilian and military applications. The use of additive manufacturing (3D printing) in fabricating small propellers was explored in this work. The effect of material (ABS) fill ratio on the performance of 3-D printed propellers was studied. It was noted that due to changes in material density, the flexibility of the propeller changed, which was reflected it in the amount of thrust produced and noise generated by these propeller. A custom built Arduino based printer was used for the fabrication and showed promising results for additive manufacturing of custom built propellers used in SAUVs. Extensive testing showed feasibility of flightworthy propellers produced through additive manufacturing.","PeriodicalId":223483,"journal":{"name":"2015 Fourth International Conference on Aerospace Science and Engineering (ICASE)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129418161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Crack growth performance of aluminum plates repaired with composite and metallic patches under fatigue loading","authors":"K. Saeed, M. Abid","doi":"10.1109/ICASE.2015.7489504","DOIUrl":"https://doi.org/10.1109/ICASE.2015.7489504","url":null,"abstract":"Composite patches, bonded on cracked or corroded metallic aircraft structures, have shown to be a highly cost effective method for extending the service life and maintaining their structural efficiency. However, there are some detrimental effects of patching dissimilar materials using a room temperature cured adhesive. To evaluate the impact of the two different patch materials on the performance of fatigue crack growth rate, we have conducted a comparative study on the patch repair performance, using composite versus metallic patches, of cracked aluminum plates. Experiments involved fatigue tests of 2 mm thick aluminum specimens with edge crack repaired with 50 mm2 patch. The notched specimens were pre-cracked to 3mm crack length before being repaired with a composite (carbon fiber) or a metallic (aluminum) patch. However, there are differences in the fatigue life using dissimilar patching materials using a room temperature cured adhesive. Fatigue test are conducted on the single sided adhesively patched 2024 T3 aluminum specimens. The crack growth behavior was monitored for different test configuration and the obtained results were compared and analyzed. In fact, although the composite material is much stronger than the metallic patches, the fatigue life of specimens repaired with metallic patches are found to be lower than that offered by composite patches. It was found that there is 15% increase in fatigue life of specimen repaired with composite patch compared to aluminum patches. Consequently, the effect of stress ratio should also be considered while bonding the cracked specimen because it has also a significant effect on the fatigue crack growth rate.","PeriodicalId":223483,"journal":{"name":"2015 Fourth International Conference on Aerospace Science and Engineering (ICASE)","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132535184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Morphotropic phase boundary in pseudo-binary Ferromagnetic Tb1−xGdxFe2 system","authors":"A. Murtaza, Yang Sen, Shahid Karim, Muhammad Tahir Khan, A. Ghani, Muhammad Sadiq Fareed, Wang Jieqiong, T. Fenghua, C. Yan, Song Xiaoping","doi":"10.1109/ICASE.2015.7489507","DOIUrl":"https://doi.org/10.1109/ICASE.2015.7489507","url":null,"abstract":"The structure and magnetic properties of ferromagnetic Tb_1-xGdxFe₂ system have been studied through the morphotropic phase boundary (MPB), a phase boundary between two ferroic phases of different crystal symmetry. Morphotropic phase boundary (MPB) has been studied extensively for its extraordinary enhancement effect in ferroelectrics. Based on same mechanism, we have designed a pseudobinary ferromagnetic system Tb_1-xGdxFe₂, of which the near-MPB composition Tb_1-xGdxFe₂ shows maximum magnetization under small field, and meanwhile dramatically the low magnetostriction. With synchrotron x-ray diffractometry, the crystal structure of TbFe₂-rich compositions is detected to be rhombohedral and that of GdFe₂-rich compositions is tetragonal below their curie temperatures. The near MPB composition Tb_0.1Gd_0.9Fe₂, shows the maximum magnetization among all available compositions and superposition of magnetostriction behavior of R and T phases. To find MPB phenomena in ferromagnets may provide a new route to design functional materials in other ferroic MPB systems.","PeriodicalId":223483,"journal":{"name":"2015 Fourth International Conference on Aerospace Science and Engineering (ICASE)","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121349561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance analysis of supervised image classification techniques for the classification of multispectral satellite imagery","authors":"Adil Nawaz, Zahid Iqbal, S. Ullah","doi":"10.1109/ICASE.2015.7489513","DOIUrl":"https://doi.org/10.1109/ICASE.2015.7489513","url":null,"abstract":"Remote Sensing is extensively used for crop mapping and management in current era. High resolution multispectral data of every part of earth is available at relatively low cost. Selection of appropriate decision rule and appropriate spectral bands is critical for obtaining accurate classification results. Need to find an accurate decision rule which is less time consuming and needs less resources leads to the performance analysis of different classification algorithms on the basis of their classification accuracy, time consumption, computational requirements, reliability etc. A SPOT 5 image acquired on 2009-07-03 from Barcelona city of Spain located at 41.3833° N, 2.1833°, and the classification algorithms i.e. Maximum Likelihood, Parallelepiped, and Mahalanobis Distance classifiers were used for the classification of the SPOT image. A spatial subset of the original imagery was created with resolution half of the original image. In this research, imagery was first atmospherically corrected using QUAC (Quick Atmospheric Correction). The spectral signature of different land classes were extracted using the spectral profile of each individual land class. The whole imagery was then classified using three Classifiers/Decision Rules i.e. Maximum Likelihood, Mahalanobis Distance and Parallelepiped Classifier. The post classification procedures i.e. clump and sieve were applied to the classified imagery to improve classification results. Maximum Likelihood Classifier outperforms other classifiers i.e. Mahalanobis Distance and Parallelepiped Classifier with Overall Accuracy (OAA) of 99.17 per cent. However these classifiers show good accuracy for classification of some classes of interest for instance the Mahalanobis Classifier outperforms the Maximum Likelihood Classifier in classifying water bodies. Results also show that the band selection is also critical in accurate classification of the imagery. The spectrally subsetted images (NIR band removed) of the same place showed very less classification accuracy than that of the original image.","PeriodicalId":223483,"journal":{"name":"2015 Fourth International Conference on Aerospace Science and Engineering (ICASE)","volume":"124 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131993980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Feasibility to adapt modifications in the extant Turbojet engine test bed for the ground test run of Turbofan engine","authors":"Nasar A. Mubarak, Syed O. Farooq, Haris A. Khan","doi":"10.1109/ICASE.2015.7489511","DOIUrl":"https://doi.org/10.1109/ICASE.2015.7489511","url":null,"abstract":"The previously extant Universal Test Bed (UTB) is a capacity to execute test run of Turbojet engines on ground before putting in place on the aircraft. This work delivers a feasibility study to modify this UTB for the Turbofan engine. Essential design modification of extant UTB is carried out by applying structural, modal and vibrational analyses for the adaptation of Turbofan engine. Physical measurements of the UTB and the mounting points of Turbofan engine reveal their mutual compatibility. Based on these measurements, two CAD models are produced in CATIA® and analyzed in ANSYS® workbench. Based on minimum stress vis-à-vis maximum Factor of Safety (FOS), the best design is finally selected based on this research.","PeriodicalId":223483,"journal":{"name":"2015 Fourth International Conference on Aerospace Science and Engineering (ICASE)","volume":"31 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116832198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}