Abstract: There is provided a method and system for positioning a transponder, the system comprising an antenna array of at least two spaced-apart antennas coupled to a common generating and switching unit. The generating and switching unit is configured for generating a periodic signal and switching the signal between said at least two antennas, constituting a positioning signal transmitted to the transponder. The system comprises a receiver for receiving a returned signal and a phase difference estimator coupled to the receiver and operable to measure phase differences between portions of the returned signal. The system further comprises a positioning utility coupled to said phase difference estimator and configured to determine the position of the transponder relative to the positioning system.

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 method for calibrating an antenna comprising a phased array of antenna elements connected to a plurality of transceivers, the method comprising providing an RF source located close to the antenna and synchronized with the transceivers, determining, per antenna element, a calibration ratio adapted to accommodate for presence of at least one interfering structure electromagnetically interfering with a signal transmitted from the RF source and received by the antenna, wherein the determining includes generating simulated far field and near field signals so as to simulate a signal transmitted by an RF source located at infinity and located near the RF source respectively, internally injecting an internal signal into the antenna via an internal injection network, using the RF source to externally inject an external signal into the antenna; and, for each individual antenna element, computing said calibration ratio by combining information characterizing the internal and external signals as received by the individ

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: A vertically stacked array antenna structure is described. The structure comprises a radiating layer, a passive layer disposed under said radiating layer, an active layer disposed under said passive layer, and an interface assembly. The radiating layer comprises an array of radiating elements. The passive layer has only passive components. At least a part of the passive components includes an array of RF duplexers corresponding to the array of radiating elements. The active layer comprises RF amplifiers. The interface assembly comprises at least one metallic frame which is in direct thermal coupling with the RF amplifiers. The interface assembly is configured for providing thermal communication of the active layer with a heat exchanger.

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: A method and a calculating circuit for generating an output signal representing an actual amplitude of a received digitized signal having a magnitude of the actual amplitude equal or greater than a value of a saturation level of a dynamic range of a receiver. For the determination of the actual amplitude, firstly, a predetermined time interval is selected. Then, a total number of samples of the received digitized signal within the predetermined time interval is calculated. Further, a number of samples of the received digitized signal within the predetermined time interval with the amplitude equal to the saturation level is calculated. Thereafter, a ratio between the number of the samples with the amplitude value equal to the saturation level and the total number of the samples is calculated. For calculation of the magnitude of the actual amplitude a predetermined relationship between the magnitude of the amplitude and the ratio is applied and the output signal representing the actual amplitude is provided.

Abstract: A free space optical communication system is described that comprises a receiver node and a transmitter node communicating to each other via a control data communication channel and an information data communication channel operating at a wavelength region different from the wavelength region of the control data communication channel. The receiver node includes a receiver unit configured to receive an information data signal provided by the transmitter node through the information data communication channel, and to recover information from said information data signal; an interrogator unit configured for generating and radiating an interrogation data signal through the control data communication channel in order to initiate and terminate an information data communication session between the receiver node and the transmitter node; and a receiver node controller configured for controlling operation of the receiver unit and the interrogator unit.

Abstract: A respective electromagnetic parameter and spatial disposition of an unknown number of signal sources in a surveillance space simultaneously bombarded by multiple signals are determined by receiving multiple signals at each of a plurality of widebeam, wideband antennas equally spaced apart in a linear array. Respective antenna signals are simultaneously sampled to generate a two-dimensional array of values. A two-dimensional Fourier transform is computed whose peaks satisfy one or more predetermined criteria, each peak being indicative of a signal source in the surveillance space, whereby the location of the peak in the Fourier transform Fjk indicates the frequency and the azimuth of the respective signal source and the amplitude of the peak indicates the amplitude of the signal source.

Abstract: A method for fabrication of an inaccessible RF microwave waveguide structure is provided. The method includes providing an RF microwave waveguide network including an array of waveguide components that have one or more apertures in a wall. The method also includes providing one or more dummy load elements made of a ceramic material having high-temperature stable properties. The dummy load elements are mounted in a predetermined place on the wall in the vicinity of the aperture. The method also includes providing a blocking assembly configured for covering RF microwave waveguide network. The blocking assembly is connected to the RF microwave waveguide network by using dip brazing.

Abstract: A respective electromagnetic parameter and spatial disposition of an unknown number of signal sources in a surveillance space simultaneously bombarded by multiple signals are determined by receiving multiple signals at each of a plurality of widebeam, wideband antennas equally spaced apart in a linear array. Respective antenna signals are simultaneously sampled to generate a two-dimensional array of values. A two-dimensional Fourier transform is computed whose peaks satisfy one or more predetermined criteria, each peak being indicative of a signal source in the surveillance space, whereby the location of the peak in the Fourier transform Fjk indicates the frequency and the azimuth of the respective signal source and the amplitude of the peak indicates the amplitude of the signal source.

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 antenna arrangement and a method for estimating the calibration ratio of an active phased antenna having a plurality of phased array antenna elements are described. The phased antenna arrangement includes a plurality of antenna elements, a plurality of receiving channels, an injection unit for injection of calibrating signals into the receiving channels, a point RF-source, located in a far field zone, a distance measurement unit, an amplitude and phase measurement unit and a data processing unit. The method comprises injecting an internal calibrating signal having a known amplitude and phase to each antenna element. An external calibration signal from a stationary RF-source is sequentially injected to all of the phased array antenna elements so that different phases of the external calibration signal arrive at each of the antenna elements.

Abstract: Sensor unit for detecting a motorized object producing a seismic or acoustic signal in the form of at least one spectral line, comprising at least one seismic sensor or at least one acoustic sensor for collecting a signal, an analog-to-digital converter for receiving said signal and generating a digital signal, a memory for storing portions of said digital signal, and a processing unit configured for performing the following operations: generating a first set of Fast Fourier Transform (FFT) values indicative of a portion of to said signal, associating said first set of FFT values with a second set of values being a partition, calculating an entropy value H of said partition, repeating the above operations, thereby constituting a sequence of entropy values H(t) corresponding to a plurality of portions of said signal, and determining a detection in case a predetermined criterion is met, said criterion is based at least on said sequence of entropy values, thereby enabling detecting of said seismic or acoustic si

Abstract: According to some embodiments of the invention a laser directed infrared countermeasures system (hereinafter: “LDIRCM system”) is mountable on a platform. According to some embodiments of the invention, a LDIRCM system may include a plurality of sector units. Each sector unit may include at least one laser unit and a laser guidance module. The laser unit may be adapted to generate a laser beam or laser energy that is intended for jamming a guidance system of a threat. The laser unit may be coupled to the laser guidance module. The laser guidance module may be adapted to steer at least a laser beam generated by the laser unit towards a threat.

Abstract: A device and a method for use in detection of a muzzle flash event is described. The device can include a Photo Detector Array (PDA), sensitive in at least a portion of the NIR and SWIR spectrum, and a filter of electromagnetic radiation selectively passing in this portion a spectral range of low atmospheric transmission, the PDA has an integration time shorter than a duration of the muzzle flash event.

Abstract: A method for calibrating an antenna comprising a phased array of antenna elements connected to a plurality of transceivers, the method comprising providing an RF source located close to the antenna and synchronized with the transceivers, determining, per antenna element, a calibration ratio adapted to accommodate for presence of at least one interfering structure electromagnetically interfering with a signal transmitted from the RF source and received by the antenna, wherein the determining includes generating simulated far field and near field signals so as to simulate a signal transmitted by an RF source located at infinity and located near the RF source respectively, internally injecting an internal signal into the antenna via an internal injection network, using the RF source to externally inject an external signal into the antenna; and, for each individual antenna element, computing said calibration ratio by combining information characterizing the internal and external signals as received by the individ

Abstract: A phased antenna arrangement and a method for estimating the calibration ratio of an active phased antenna having a plurality of phased array antenna elements are described. The phased antenna arrangement includes a plurality of antenna elements, a plurality of receiving channels, an injection unit for injection of calibrating signals into the receiving channels, a point RF-source, located in a far field zone, a distance measurement unit, an amplitude and phase measurement unit and a data processing unit. The method comprises injecting an internal calibrating signal having a known amplitude and phase to each antenna element. An external calibration signal from a stationary RF-source is sequentially injected to all of the phased array antenna elements so that different phases of the external calibration signal arrive at each of the antenna elements.

Abstract: Detection of at least one object causing a signal of interest. In one embodiment, a method of detecting at least one object causing a persistent non-random pressure wave comprises: providing a digital signal representation of the pressure wave that includes respective amplitudes of the signal, in at least two different frequencies, and providing a detection indication based on a measured similarity between the respective amplitudes over time.

Abstract: A method for fabrication of an inaccessible RF microwave waveguide structure is provided. The method includes providing an RF microwave waveguide network including an array of waveguide components that have one or more apertures in a wall. The method also includes providing one or more dummy load elements made of a ceramic material having high-temperature stable properties. The dummy load elements are mounted in a predetermined place on the wall in the vicinity of the aperture. The method also includes providing a blocking assembly configured for covering RF microwave waveguide network. The blocking assembly is connected to the RF microwave waveguide network by using dip brazing.