Informatics Publishing Limited

K. Prameela ¹, S. Umamaheswararao ¹, P. Sirish Kumar ¹, M. N. V. S. S. Kumar ¹

Affiliations
1 Department of Electronics and Communication Engineering, AITAM, IN

Abstract

The words broadcasting, unicasting and multicasting are the well familiar terms in the field of communications and are very important in describing various parameters in designing the system. In the field of communications, the applications which involve broadcasting needs an antenna of high directivity and should use the power effectively (low side lobes). Where in applications that needs unicast-reception mainly needs high directivity (Zone of reception) and low interference (low side lobes) antennas. There are some special applications like tracking radars, surveillance antennas demand patterns with special characteristics (Beam widths). Due to the non complexity in implementation and ability to produce symmetrical-high directive beams, generally planar array antennas are used in above mentioned applications. Planar antennas, with compromise in increased number of elements and size, produces high directive beams. Other way of generating desired beam pattern is by synthesizing the antenna radiation pattern. Schelkunoff polynomial synthesis method is one being used in linear array design for suppressing radiation in undesired directions, there by increases the directivity. In order to produce the desired beam with high directivity this paper proposes a planar array design method and also extends the schelkunoff polynomial method (confined as linear array synthesismethod) to planar array design to produce cost effective high directive antennas. The radiation pattern characteristics Directivity, 3dB beam width, Null-Null beam width and side lobe levels are used to analyse the performance of proposed design and algorithm.

Keywords

Linear Array, 3D Planar Array, Schelkunoff Polynomial Method, Directivity.

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S. Sateesh ¹, M. N. V. S. S. Kumar ¹, M. Bala Krishna ¹, V. Laxmi ¹

Affiliations
1 Department of Electronics and Communication Engineering, Aditya Institute of Technology and Management, Tekkali, IN

Abstract

Due to the increase in popularity of wireless networks, there is a need of combining various heterogeneous networks to provide global information access to the user. Vertical handoff is an exciting and a latest scheme that intends at combining different network interfaces. The most decisive parameter which plays an important role in certain mobile nodes is battery power. Due to the complexity of vertical handoff algorithms previously developed, the battery power of certain mobile nodes is almost exhausted at the end of execution of algorithm. Moreover, as mobile nodes operate with limited battery power, when battery level falls below a specific level, handing off to a network with low power consumption can provide extended usage time. Thus there is a necessity to develop a vertical handoff algorithm with minimum complexity. In this paper, a new vertical handoff algorithm is developed which aims at taking an optimal handoff decision using two simple steps. Unlike the previous developed algorithms, this algorithm discriminates resource rich and resource poor mobile stations during the execution of the algorithm. Due to the consideration of dynamic new call blocking probability during handoff decision, this algorithm helps in connecting to the optimal network in the vicinity of the mobile station.

Keywords

Handoff, Received Signal Strength, Call Dropping Probability.

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Elena Popel ¹, M. Vijaya Deepti ¹, M. N. V. S. S. Kumar ²

Affiliations
1 Stratford University, Virginia, US
2 Andhra University, IN

Abstract

With increasing demand for software products Software Quality Assurance (SQA) is recognized as a good approach to quality problems. SQA is a planned approach to make sure software processes and products perform according to the standards. The goals of software quality assurance are to improve software quality by appropriately monitoring both software and the development process to ensure full compliance with the established standards and procedures. There may be errors in software which are might not necessarily be introduced during the preliminary stages when the development of the code takes place but also at subsequent stages during the design and programming faults implementation. Thus there is a necessity for one to develop software along with quality assurance activities to ensure the proper working of the development. Software controlled measuring systems can be approved with the help of different kinds of conformity assessment techniques based either on the final product, the product design or corresponding development and production processes. In this paper the stages of Software Quality Assurance like Software Quality Assurance in Software Development Cycle, System/Information Engineering and Modeling, Software Requirement Analysis are discussed.

Keywords

Software Quality Assurance, Software Quality Control, Software Verification and Validation.

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Rajkumar Goswami ¹, G. Sasi Bhushana Rao ², S. Swapna Rani ¹, M. N. V. S. S. Kumar ³, S. Deva Prasad ³, G. Hemanth Kumar ⁴

Affiliations
1 Andhra University, IN
2 Electronics and Communication Department, Andhra University, Visakhapatnam, IN
3 Andhra University, Visakhapatnam, IN
4 GNITS, Hyderabad, IN

Abstract

With the advancement of technology, the imaging sonars have become the reality and their usage has been extensive in the area of obstacle avoidance in respect of Autonomous Underwater Vehicle (AUV). The underwater environment being heterogeneous, the sonar images have a very complex background, low contrast, and deteriorative edges. These characteristics, therefore, pose the difficulties for extracting the objects from the sonar images. In this paper we have reviewed the various existing image processing techniques in respect of the sonar images and discussed their shortcomings. After discussing the existing image processing techniques and their limitations, an algorithm has been proposed for processing these sonar images effectively and the results have also been compared with the results of existing techniques. Extracting the obstacle (objects) aspects such as range, bearing, size, shape, speed and course from the images received from Sonar are very important for the AUV in order to avoid the collision from the obstacles those may come into its path. Another very important criterion is the time taken to process the image, which must be as least as possible in order to provide more time for the AUV to take evasive action. For achieving this, proper segmentation of sonar images is a very important step in order to identify the objects (or obstacles) correctly in the least possible time. Several algorithms have been developed in the past for segmentation of images, however these methods did not provide the desired results when subjected to the real sonar images. Therefore a new segmentation method for processing the underwater Sonar images was developed by taking into account the available techniques and domain knowledge. This method is based on the thresholding of the image in which the threshold is calculated adaptively on iterative basis by taking the parameters of image histogram into consideration. The initial threshold value for each individual region of image has been selected by taking the histogram of the region under consideration. Adaptive thresholding utilizes a local window for each individual pixel and computes the new intensity value, based on the local histogram defined in the local window. This is then followed by the morphological, dilation and erosion operations before producing the final segmented image. The performance of the proposed algorithm has been compared with the other existing methods such as Edge detection, Adaptive Thresholding, Fuzzy C Means Clustering (FCM) and Adaptive Histogram Equalization. The results have also been presented in the tabulated form in addition to the segmented images. It has been concluded from the results that the proposed segmentation method achieves better segmentation results in respect of sonar images and is also highly efficient as it takes the least time for segmentation amongst all the methods.

Keywords

Adaptive Threshold, Histogram, Segmentation, Sonar.

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G. Sasi Bhushana Rao ¹, Rajkumar Goswami ², S. Deva Prasad ³, M. N. V. S. S. Kumar ⁴, S. Swapna Rani ⁵

Affiliations
1 Electronics & Communication Engineering Department, Andhra University Engineering College, Visakhapatnam, IN
2 Andhra University College of Engineering, Visakhapatnam, IN
3 University College of Engineering, Andhra University, Visakhapatnam-530003, IN
4 Department of Electronics & Communication Engineering, University College of Engineering, Andhra University, Visakhapatnam-530003, IN
5 Electronics and Communication Engineering Department, Andhra University, Visakhapatnam, IN

Abstract

With the advent of Imaging SONAR, the field of underwater imaging has been gaining lot of importance especially for Autonomous Underwater Vehicle (AUV) for obstacle avoidance.AUV is the underwater robot used for detecting the underwater mines, monitoring and surveillance of coastline and important dense traffic movement ports and other vital defence installations. The AUV applications include the obstacle trajectory tracking, obstacle avoidance and intelligence surveillance and reconnaissance(IRS). The heart of the AUV system depends on the performance of the SONAR. SONAR provides the navigation and guidance by mounting it on the AUV and operates on the principle of acoustic wave propagation. SONAR provides only the location of the object in terms of range and bearing and the objects dimensions (length and thickness) but not the obstacle depth information. For effective maneuvering and for analyzing the target features especially for collision avoidance, the depth information of the object in 3Dimensions is important. In order to know the depth of the obstacle using 2D SONAR, the 2-Dimensional images of the obstacle at different elevation angles are obtained and are used to reconstruct the 3D. This is achieved by scanning the object at various depths. There can be two conditions one in which the SONAR beam partially covers the object, and the second in which SONAR beam covers the complete object. The algorithms developed for this analysis of SONAR data demonstrate the usefulness of the proposed system in the process of converting 2D to 3D information. In this paper a method along with the algorithm that has been designed and developed to calculate the aspect of the target in 3 Dimensions from the 2 Dimension images received from the imaging SONAR by scanning the objects at the various depths is presented. It has been concluded that by using the proposed method and by implementing the proposed algorithm in the 2D SONAR, the high precision 3D aspect of objects has been achieved. The main advantages of proposed algorithm are cost saving and high precision of reconstructed objects.

Keywords

2-Dimensional, 3-Dimensional, AUV, SONAR.

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Y. Ramana Murty ¹, M. Bala Krishna ¹, M. N. V. S. S. Kumar ¹

Affiliations
1 Aditya Institute of Technology and Management, Tekkali, IN

Abstract

Avoiding collision of the Autonomous underwater vehicle (AUV) with the floating or fixed objects in the underwater scenario needs either apriori knowledge of the operating environment or sensing equipment for evaluating the environment in real time. The sensing equipment in this case is the forward looking Sonar that is mounted on the AUV which scans the area in front and provides the images as the output. The technology used in this forward looking SONAR is CHIRP. In SONAR, Surface Acoustic Wave devices such as Reflective array Compressors are used to generate the chirped signals. Because of Chirp technology high resolution images of sea bed are produced. The range resolution of the CHIRP technology SONAR is much better than conventional monotonic SONAR. With monotonic SONAR it is very difficult to differentiate two objects separated by less than 37.5 mm whereas using CHIRP technology SONAR it is easy to distinguish the objects if they 7.5mm apart. In this paper the generation of Chirp pulse is analyzed. The pulse compression technique and different windowing techniques are analyzed to detect the peak of the received signal.

Keywords

Chirp, Range Resolution, Pulse Compression.

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L. Vijaya Lakshmi ¹, A. Jaya Laxmi ², M. N. V. S. S. Kumar ¹, P. Sirish Kumar ¹

Affiliations
1 Department of ECE, Aditya Institute of Technology and Management, Tekkali, Andhra Pradesh, IN
2 Department of ECE, Aditya Institute of Technology and Management, Tekkali, Andhra Pradesh

Abstract

It is very important to know the characterization of targets using radar. It is extensively used in various applications. The polarization properties are important for radar target besides amplitude, phase and frequency. The polarization may be potentially used to improve target detection, anti-interference, and radar target recognition. Characteristics of the target can be known by using the polarization properties of that particular target. This depends upon scattering nature of the target. Using polarization scattering matrix (PSM), we can obtain the properties of the target. The derivations of scattering matrix for some other various geometrical shapes are presented in this paper. By using the method of the properties of polarization scattering matrix (PPSM) for radar target recognition (RTR) is presented in this paper. The polarization matrix and properties for a dipole is calculated by considering that dipole as target. These properties of the polarization scattering matrix are analyzed for different orientation angles for a target.

Keywords

Polarization, Scattering Matrix.

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M. N. V. S. S. Kumar ¹, Nagamani Modalavalasa ², L. Ganesh ³, K. Satya Prasad ², G. Sasibhushana Rao ⁴

Affiliations
1 Department of Electronics and Communication Engineering, Aditya Institute of Technology and Management, Tekkali, Srikakulam Dist. 532 201, IN
2 Department of Electronics and Communication Engineering, Jawaharlal Nehru Technological University, Kakinada 533 003, IN
3 Department of Electronics and Communication Engineering, Anil Neerukonda Institute of Technology and Sciences, College of Engineering, Visakhapatnam 531 162, IN
4 Department of Electronics and Communication Engineering, Andhra University, Visakhapatnam 530 003, IN

Abstract

Obstacle avoidance and navigation is a demanding task for an autonomous underwater vehicle (AUV) due to the complex nature of the underwater environment. However, an automatic detection and tracking system is the primary element for an AUV or an aqueous surveillance network. Tracking underwater objects in an active context, represents an ongoing challenge in the field of signal processing. In order to detect the target's presence under water, the echoes reflected by the target are analysed by the receiver. Track accuracy is one of the paramount performance measures of a tracking system. Towards this, various methods such as Kalman filter (KF), extended Kalman filter (EKF) and least squares (LS) have been explored. However, all these methods have their own drawbacks. In this study, a new approach called modified gain EKF has been implemented on the simulated data for tracking of underwater moving object using bearing and elevation measurements. AUV fitted with a single sonar is used for validating the proposed bearing and elevation only tracking (BEOT) algorithm. The performance of the algorithm is evaluated in Monte Carlo simulations and results are presented in stipulated geometries.

Keywords

AUV, BEOT, EKF, Obstacle Avoidance, Tracking.

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