Binay Kumar Sarkar

Augmentation of Anti-Jam GPS System Using Smart Antenna with a Simple DOA Estimation Algorithm

Smart Antenna system analysis presented with multipath and null constraint for reducing interference and efficient use of spectrum with the help of LMS algorithm for GPS (Global Positioning System) System. A new simple DOA (Direction of Arrival) estimation method by rotation of antenna plane proposed. Simulated Result obtained using MATLABTM.

Incorporation of Anti-Jamming Techniques in a GPS Receiver

GPS guidance uses low power signals from satellites which are 11000 NMI away. The satellite transmitter power is modest nearly 10 W orders of magnitude. Neither satellite nor receivers have the luxury of very high antenna gain since both entities have significant field of view requirements. These factors result in a very low power density incident on a GPS receiver antenna. The signal received is generally 165 dB down than the thermal noise level. Such signals are notoriously easy to jam either by intentional noise sources (Jammer) or unintentionally from harmonics of broadcasting stations or other out of band sources. Here in this paper we will show how a nulling antenna or controlled reception pattern antenna with adaptive spatial filtering technique efficiently mitigate the intentional and non intentional interferences.

SMART ANTENNA BASED DS-CDMA SYSTEM DESIGN FOR THIRD GENERATION MOBILE COMMUNICATION

SMARTANTENNABASEDDS-CDMASYSTEMDESIGNFORTHIRDGENERATIONMOBILECOMMUNICATIONA.KunduKalpanaChawlaSpaceTechnologyCell(KCSTC)DepartmentofElectronics&ElectricalCommunicationEngineeringIndianInstituteofTechnologyKharagpur721302,IndiaS.GhoshNetajiSubhashEngineeringCollege(NSEC)DepartmentofECEWestBengalUniversityofTechnologyIndiaB.K.SarkarandA.ChakrabartyKalpanaChawlaSpaceTechnologyCell(KCSTC)DepartmentofElectronics&ElectricalCommunicationEngineeringIndianInstituteofTechnologyKharagpur721302,IndiaAbstract—The third generation promises increased bandwidth upto 384Kbits/s for wide area coverage up to 2Mbits/s for localarea coverage. A smart antenna technique has been developedspecifically to meet the bandwidth needs of 3G [5,7,12,14]. Smartbeamforming provides increased data throughput for mobile highspeed data application. Here in this paper we worked on MVDRBeamformingschemeforcontinuingdemandforincreasedbandwidth&betterqualityofservices. Adaptiveminimumvariancebeamformingcanbeeasilyimplementedtoincreasecapacityaswellassuppressingco-channel interference & to enhance the immunity to fading. ThecomputersimulationcarriedoutinMATLABplatformshowsthesignalprocessingtechniqueoptimallycombinesthecomponentsinsuchawaythat it maximizes array gain in the desired direction simultaneouslyminimizeitinthedirectionofinterference[1,3,15,16].

Passive Radar using Multiple GSM Transmitting Stations

The atmosphere has a wide range of transmissions available from various sources like TV transmissions, GSM signals, FM Radio, AM Radio, GPS signals, etc. These signals open up the opportunity of designing different types of passive radars. Passive radar using a single GSM transmitting station have been designed, but this type of radar cannot give accurate target parameters. This paper suggests a passive radar using signals from multiple GSM base stations to provide better accuracy of target parameters.

Effect of Element Characteristic on the Scanning Range of a Phased Array Radar

The radiation pattern for an scanned beam in a array is given by the product of the single element pattern multiplied by the array factor. Though the overall radiation pattern is decided by the array factor since it is narrower than element pattern, the element pattern is required to be wider so that narrower array factor is not outside the element pattern. Otherwise, the beam peak will not move though the phase shifts between elements are changed to move the beam. The result is shown by simulation for microstrip patch and vivaldi notch radiators array microwave studio software

Generalized mechanism of SOTDMA and probability of reception for satellite-based AIS

Satellite based ‘Automatic Identification System’ (AIS) for global maritime applications is of current interest. The challenge of the system mainly lies in the detection capability of the receiver due to multiple transmissions from different ships received at the satellite simultaneously. To estimate the performance of the receiver proper modeling of the channel access scheme is important. In this paper we propose a generalized methodology of the Self Organized Time Division Multiple Access (SOTDMA) in an extended observation area for satellite based AIS. The performance of the proposed scheme is compared with an existing model and more realistic reception performance by a satellite based receiver is shown.

Analysis of circular patch antenna as an electromagnetic interference sensor

This paper presents the analysis of circular patch antenna as an electromagnetic interference sensor in microwave frequency range. The paper describes the performance of circular patch antenna as EMI sensor in terms of antenna factor and radiation characteristics. The designed patch antenna is simulated using commercial software Computer Simulation Technology Microwave Studio. The designed patch antenna is fabricated and characteristics are measured. Simulated and experimental results are presented and discussed. Same trend is obtained in the antenna factor of the circular patch antenna calculated from experiment and simulation.

RF MEMS DMTL phase shifter on low-resistivity silicon for Ku band with reduced substrate loss

Distributed MEMS transmission line (DMTL) phase shifter on low resistivity silicon for Ku band is presented. The loss relating to the conductivity of silicon and carriers at the silicon-oxide interface is solved by completely removing the silicon as well as the oxide from underneath the CPW t-line. The only silicon left is to provide anchorage to movable sections of the CPW. This also results in a two movable plate system which simultaneously improves the actuation voltage and the switching speed. A phase shifter based on the two movable plate system is designed and a phase shift of 180° is obtained at Ku band with an insertion loss of 1.16dB for low resistivity silicon (10–20 Qcm). A fabrication technique is proposed and initial fabrication results of the design are presented.

Implementation Issues of Adaptive Array Processing for Space borne GPS Receiver

Research and development continues to extend the capabilities and to increase the robustness of global positioning systems (GPS) receivers. Adaptive array antenna have been widely used for GPS receiver for antenna beam-forming & nulling due to its sensitivity to signal multipath and intentional & non-intentional noise sources. It is obvious that the optimum array processing is the best suitable mitigation technique. This RF beam-forming employed in the GPS receiver leads the recent research methodology to mixed mode signal processing. A real time field programmable gate array (FPGA) implementation of MVDR beam-forming were presented here.

Switched Beam Array Antenna for Sectorized Optimum Power Distribution into Discrete Localities of Rural Area

The technology of Switched Beam Array Antenna for mobile communications has received enormous interest worldwide in recent decade. This type of smart antenna (another type is Adaptive Array Antenna) forms a pattern that adapts to the current radio conditions improving the communication link. The principal reason for applying Switched Beam Array Antenna is the possibility for a large increase in capacity and to introduce new services. The purpose of this paper is to give a performance analysis of Switch Beam Smart Antenna (SBSA) using micro strip patch elements with simulation results obtained by using CST Microwave StudioTM, in KCSTC of IIT Kharagpur.