Abstract: There is provided a system and method for positioning a receiver, the system comprising an antenna array coupled to a common generating and switching unit. The generating and switching unit is configured to generate a periodic signal and to switch the signal between at least two antennas, constituting a positioning signal; such that an RF receiver receiving the positioning signal and having a phase difference estimator is capable to measure phase differences between portions of the positioning signal transmitted by the spaced-apart antennas, the phase differences indicating the orientation of the received relative to the positioning system.

Abstract: A method and system for SNR enhancement in pulse-Doppler coherent target detection. In accordance with the method of the invention, complex signals are obtained for each of two or more sub-intervals of the time-on-target interval, allowing simultaneous rang and Doppler measurements. A coherent integration is then performed on the signals to generate complex-valued folded matrices. The folded matrices are unfolded and target detection is then performed in a process involving one or more of the unfolded matrices. A pulse-Doppler coherent system is also provided configured for target detection by the method of the invention.

Abstract: A light projection optical system is presented. The system comprises a cooling chamber containing: a light source operative at a cool temperature being lower than 240K; a cooler unit capable of cooling said light source to said cool temperature during the light source operation, an optical window permitting light emergence outside from the cooling chamber; and an optical unit accommodated in the optical path of light emitted by said light source and enabling emergence of this light through said optical window outside from the cooling chamber.

Abstract: The present invention provides a method for intercepting and monitoring of cellular satellite communication wherein communication between at least one mobile device (MES) and the satellite is through a first band link that includes plurality of first-band spot beams each accommodating at least one basic channel unit that includes a control channel and corresponding traffic channels, and communication between the satellite and main station is through wideband second-band link accommodating plurality of second band spot beams each accommodating at least one basic channel unit that includes a control channel and corresponding traffic channels, the method comprising detecting map between a control channel of the downlink first band link and corresponding control channel of downlink second band link by identifying identical unique spot beam number (SB Mask) data in the respective control channels.

Abstract: The present invention provides an apparatus and method for intercepting and monitoring communications between target mobiles and a main station of a satellite communication system, wherein communication between the mobiles and a satellite is achieved by using a first-band spot beams, chosen by the mobiles and wherein communication between the satellite and the main station is achieved by using a wideband second-band link, and wherein the satellite is operable to change the mapping scheme of the first-band frequencies to the second-band frequencies, the apparatus comprises: at least one RF second-band and at least one RF first-band receive antenna which transmits the received signals to at least one RF second-band and at least one first-band receiver respectively; an intermediate frequency RF distributor which receives signals from said RF second-band and RF first-band receivers and splits the transmission into groups of frequencies; a plurality of demodulators which are tuned to cover sequentially the first-b

Abstract: A phased array radar antenna includes at least two antennas (11, 12, 13, 14) adapted for simultaneous operation at different non-mutually interfering frequencies. The phased array radar antenna may be fitted to an aircraft having a fuselage supporting first and second radar side antennas (11, 12) on opposite sides thereof, a nose portion supporting a first radar end antenna (13), and a tail portion supporting a second radar end antenna (14). Respective radomes cover the first and second radar end antennas so as to provide a smooth aerodynamic contour, and a radar control unit (15) is disposed within the fuselage and coupled to the first and second radar side antennas and to the first and second radar end antennas for operating the first or second radar side antenna simultaneously with the first or second radar end antenna at respective first and second different frequencies.

Abstract: Change detection apparatus for detection of changes between first and second stereoscopic image pairs obtained at different times of a substantially similar view, comprises: a two-dimensional image filter for comparing first and second image pairs to obtain an initial list of change candidates from two-dimensional information in the image pairs, and a three-dimensional image filter for comparing the image pairs at locations of the change candidates using three-dimensional image information. The apparatus retains those change candidates correlating with three-dimensional image change and rejects change candidates not correlating with three-dimensional image change, and produces a refined list of change candidates.

Abstract: A waveguide slot antenna element, waveguide slot antenna arrays comprising a plurality of the waveguide slot antenna elements and a method of operating the waveguide slot antenna arrays are described. The waveguide slot antenna element includes a non-radiating side including a feeding port, a radiating side disposed opposite to the non-radiating side and including at least one pair of radiating slots, and an energy splitter arrangement accommodated between the radiating and non-radiating sides along a path of an ingress electromagnetic field propagating from the feeding port towards said at least one pair of radiating slots. The method of operating the waveguide slot antenna arrays includes supplying electromagnetic energy of a predetermined frequency to the feeding ports of a first pair of slot antenna linear arrays and a second pair of slot antenna linear arrays independently of each other, thereby to generate an electromagnetic field of desired polarization.

Abstract: A calibration method and a system for providing calibration data for use with a direction finder are provided. The method comprises providing a relative motion of a calibration receiver in a circle manner with respect to calibration transmitter at a predetermined distance from each other. The method also includes preparing and transmitting a communication frequency signal employed for transmitting a certain frequency from a list of predetermined frequencies. The preparing comprises: (a) setting a value of the dwell time ranges of the communication frequency signal to a predetermined value; (b) synchronizing in time the dwell time ranges between the calibration transmitter and the calibration receiver by using clock signals of a common synchronization source; (c) providing a hop duration time interval within the dwell time range for transmitting the frequency; and (d) generating the communication frequency signal corresponding to the frequency during the hop duration interval.

Abstract: A method of suppressing grating lobes generated in a radiating pattern of a phased array antenna, and a patch antenna element for use in the phased array antenna are described. The phased array antenna is formed from a plurality of symmetrical patch antenna elements spaced apart at a predetermined distance from each other. Each patch antenna element is configured for producing an asymmetrical radiation pattern. The antenna element includes a conductive ground plane, a radiating patch backed by a cavity and arranged in cavity aperture, and a feed arrangement. The patch antenna element is configured such that a dimension of the radiating patch along the E-plane of the antenna element is less than the dimension of the cavity aperture by a first predetermined value selected to provide an asymmetrical radiation pattern of the patch antenna element.

Abstract: Methods and systems for distributing processing of computerized tasks from a client to one or more servers. One embodiment of the present invention describes producing task information and conveying the task information to a distribution processor. Another embodiment describes receiving inquiry data, retrieving from a repository task data indicative of a task that a specific server is competent to perform, producing data that is representative of the task data, and conveying the produced data to the specific server. Yet another embodiment describes obtaining competency data pertaining to tasks that a server can carry out and conveying the competency data to a distribution processor for receiving data representative of a task.

Abstract: A monopole fractal antenna and a method of manufacturing thereof are described. The antenna includes a ground plane having a cavity recessed therein, a radiating arm backed by the cavity and coupled to a feeding line arranged at the cavity, and at least one pair of electrical shunts configured for connecting at least two points selected within the fractal portion of the radiating arm to the ground plane. At least a portion of the radiating arm has a fractal geometric shape. The radiating arm is extended from the cavity along an axis disposed in relation to the ground plane.

Abstract: A method of suppressing grating lobes generated in a radiating pattern of a phased array antenna, and a patch antenna element for use in the phased array antenna are described. The phased array antenna is formed from a plurality of symmetrical patch antenna elements spaced apart at a predetermined distance from each other. Each patch antenna element is configured for producing an asymmetrical radiation pattern. The antenna element includes a conductive ground plane, a radiating patch backed by a cavity and arranged in cavity aperture, and a feed arrangement. The patch antenna element is configured such that a dimension of the radiating patch along the E-plane of the antenna element is less than the dimension of the cavity aperture by a first predetermined value selected to provide an asymmetrical radiation pattern of the patch antenna element.

Abstract: A waveguide slot antenna element, waveguide slot antenna arrays comprising a plurality of the waveguide slot antenna elements and a method of operating the waveguide slot antenna arrays are described. The waveguide slot antenna element includes a non-radiating side including a feeding port, a radiating side disposed opposite to the non-radiating side and including at least one pair of radiating slots, and an energy splitter arrangement accommodated between the radiating and non-radiating sides along a path of an ingress electromagnetic field propagating from the feeding port towards said at least one pair of radiating slots. The method of operating the waveguide slot antenna arrays includes supplying electromagnetic energy of a predetermined frequency to the feeding ports of a first pair of slot antenna linear arrays and a second pair of slot antenna linear arrays independently of each other, thereby to generate an electromagnetic field of desired polarization.

Abstract: A calibration method and a system for providing calibration data for use with a direction finder are provided. The method comprises providing a relative motion of a calibration receiver in a circle manner with respect to calibration transmitter at a predetermined distance from each other. The method also includes preparing and transmitting a communication frequency signal employed for transmitting a certain frequency from a list of predetermined frequencies. The preparing comprises: (a) setting a value of the dwell time ranges of the communication frequency signal to a predetermined value; (b) synchronizing in time the dwell time ranges between the calibration transmitter and the calibration receiver by using clock signals of a common synchronization source; (c) providing a hop duration time interval within the dwell time range for transmitting the frequency; and (d) generating the communication frequency signal corresponding to the frequency during the hop duration interval.

Abstract: A dipole fractal antenna and a method of manufacturing thereof are described. The antenna includes a pair of oppositely directed radiating arms coupled to a feeding terminal and extended therefrom along a central axis in a common plane. At least a portion of each radiating arm has a fractal geometric shape. The antenna also includes at least one pair of electrical shunts configured for connecting at least two points selected within the fractal portion of one radiating arm correspondingly to two points selected within the fractal portion of another radiating arm. The dipole fractal antenna further may comprise a balun arranged at the feeding terminal and configured for coupling the pair of oppositely directed radiating arms to a coaxial cable to provide a balanced feed.

Abstract: A phased array antenna system accommodating onto a platform for tracking a target moving relatively to the platform, the antenna system comprising a first planar active subsystem operable for receiving/transmitting an RF signal of a certain linear polarization direction and for selectively performing electronic scanning; a second, roll subsystem coupled to the active subsystem and operable for rotational movement of the active subsystem about a first axis perpendicular to a plane defined by the planar active subsystem; a third, elevation subsystem coupled to the second, roll subsystem and to a fourth azimuth subsystem, the azimuth subsystem defining a central axis of the antenna system and being operable for providing rotational movement of the first planar subsystem about the central axis, the elevation subsystem being configured to provide a certain angular orientation between the plane defined by the active subsystem and a plane defined by the azimuth subsystem, thereby allowing positioning the first plana

Abstract: The present invention provides for an antenna and a method for providing an antenna for transmitting and/or receiving electromagnetic waves of at least one predefined frequency and a circular polarization, the antenna comprising at least a first support having upper and lower faces and at least one pair of substantially identical upper and lower radiating elements disposed on the upper and lower faces, respectively, each radiating element being capable of transmitting and/or receiving electromagnetic waves of circular polarization with a phase center located at a predefined position.

Abstract: A phased array antenna system accommodating onto a platform for tracking a target moving relatively to the platform, the antenna system comprising a first planar active subsystem operable for receiving/transmitting an RF signal of a certain linear polarization direction and for selectively performing electronic scanning; a second, roll subsystem coupled to the active subsystem and operable for rotational movement of the active subsystem about a first axis perpendicular to a plane defined by the planar active subsystem; a third, elevation subsystem coupled to the second, roll subsystem and to a fourth azimuth subsystem, the azimuth subsystem defining a central axis of the antenna system and being operable for providing rotational movement of the first planar subsystem about the central axis, the elevation subsystem being configured to provide a certain angular orientation between the plane defined by the active subsystem and a plane defined by the azimuth subsystem, thereby allowing positioning the first plana

Abstract: An arrangement for introducing a plate element, for which heat needs to be dissipated by means of conduction, into a slot of a chassis which is adapted to absorb the heat. The slot has a back wall adapted to contact the plate element upon its insertion, an opposing front wall, and a base wall. The plate element has margins adapted for carrying the arrangement. The arrangement comprises has a seat located on the margins. The arrangement further has a wedgelock moveably attached to the seat, having two slot engaging surfaces adapted to contact the front and base walls of the slot, and a seat engaging portion adapted to contact the seat.