Abstract: A monitoring system for an inner area of a machine includes a radar source radiating or injecting radar radiation into the inner area and a radar receiver receiving radar radiation reflected in the inner area and emitting the reflected radar radiation as a received signal. A control and evaluation unit determines an actual signature from the received signal and compares the actual signature to a stored nominal signature representing a fault-free machine. An output unit outputs a fault error signal when a discrepancy between the actual signature and the nominal signature exceeds a tolerance value.

Abstract: A method and system for detecting chaff is disclosed. The method includes receiving range profile data including a plurality of samples, determining an average power for a first group of samples of the range profile data and a second group of samples of the range profile data, comparing the average power for the first group of samples to a first threshold value and the average power for the second group of samples to a second threshold value, and identifying a chaff detection if an average power of at least one of the first and second groups of samples exceeds its respective threshold value. The system includes a computer readable medium and a processor in communication with the computer readable storage medium and configured to perform the receiving, determining, comparing and detecting steps.

Abstract: Systems and methods to determine electromagnetic properties are provided. A particular method includes directing electromagnetic energy toward an article under test. The method also includes taking measurements of electromagnetic energy scattered by the article under test. The method further includes determining expected baseline values of at least one electromagnetic property of the article under test. The expected baseline values are based on electromagnetic energy scattered by a control article. The method also includes determining output data based on a difference between the expected baseline values and characteristic values of the article under test determined based on the measurements of electromagnetic energy scattered by the article under test. The output data includes values indicative of inhomogeneous distribution of an electromagnetic property of the article under test.

Abstract: The embodiments are related to deploying wireless devices in a space to maximize a monitored area. In an embodiment, the system includes at least one first wireless device installed into a first position and set in a placed mode, and a second wireless device to be installed into a second position and set in an unplaced mode. The second wireless device is moved away from the at least one first wireless device. An application message is transmitted at a normal operating power. A link quality detection message is transmitted at a reduced power lower than the operating power by a headroom. The link quality between the at least one first wireless device and the second wireless device is estimated based on the link quality detection message to determine the second position to install the second wireless device. Once installed, the second wireless device is switched to the placed mode.

Abstract: A radiofrequency circuit embedded onboard a satellite, data being transmitted on several channels by radiofrequency signals, includes a channel corresponding to a frequency band, and a succession of gains being able to be associated with a channel so as to generate the radiofrequency signal to be transmitted on the latter. The succession includes at least one variable-gain amplifier, the radiofrequency signals thus generated being multiplexed by a multiplexer composed of bandpass filters. The successions of gains comprise a power load arranged so as to dissipate the power of signals which is reflected by the filters of the multiplexer, said load including means for generating an alarm signal representative of the power level of the reflected signals, the alarm signal being used to control the gain of the variable-gain amplifier. The subject of the invention is also a power load.

Abstract: An apparatus for sensing motion having a transmitter for transmitting a carrier signal; a frequency control connected to the transmitter for controlling the frequency of the carrier signal; a first receiver for receiving the reflected transmitted carrier signal; a second receiver for receiving the reflected transmitted carrier signal, the second receiver being placed out of phase by less than a wavelength of the carrier signal from the first receiver; means for subtracting the carrier signal received by the second receiver from the carrier signal received by the first receiver to produce an error signal; wherein when motion is sensed by the apparatus, the error signal moves from zero thereby causing a corrective signal to be generated and sent to the frequency control, the frequency control forcing the error signal to zero.

Abstract: Provided are a sensor capable of adjusting vertical alignment and a sensor vertical alignment adjusting apparatus using the same. The sensor has a structure with a plurality of switchable transmitting and receiving antennas so as to be able to adjust the vertical alignment, or a structure with a tilting motor for adjusting a radiating or receiving angle. The sensor vertical alignment adjusting apparatus using such a sensor corrects vertical misalignment of the sensor by determining whether or not the vertical misalignment of the sensor occurs, variably switching one from among the plurality of transmitting or receiving antennas of the sensor or controlling the tilting motor, and adjusting the radiating angle of the sensor signal or the receiving angle of a reflected wave of the sensor signal.

Abstract: A calibration system for a dual polarization radar system with built in test couplers has been developed. The system includes a dual polarization radar transmitter antenna that generates a transmission pulse. A test coupler is located behind the antenna that reads a sample of the transmission pulse a test signal. A calibration circuit receives the sample of the transmission pulse and generates a test signal that simulates a desired atmospheric condition. Finally, a test antenna transmits the test signal to the dual polarization radar transmitter antenna for calibration of the system.

Abstract: A method examining an object using millimeter-wave signals includes: (a) providing at least two millimeter-wave signal sources; (b) transmitting at least two millimeter-wave signals having at least two different frequencies from the signal sources illuminate the object; (c) in no particular order: (1) determining whether a return reflected signal is above a threshold level; [a] if yes, processing the return signal to identify object shape; [b] if not, processing another return signal; and (2) determining whether a return intermodulation product or harmonic signal is detected; [a] if yes, processing the return signal to identify object nature; [b] if not, processing another return signal; (d) determining whether checked all return signals; (1) if not, processing another return signal; (2) if yes, proceeding to step (e); (e) determining whether results are satisfactory; (1) if not, changing frequency of at least one of the wave signals; (2) if yes, terminating the method.

Abstract: A radar system tracks targets, and for each target determines the maximum acceleration of the target which can be tracked. The target acceleration is compared with the maximum acceleration that the radar can maintain in track, and if the decision is that the radar cannot maintain track, the radar data rate is increased, at least for that target. In at least some cases in which the target acceleration is such that the target can be maintained in track, the data rate for that target is decreased.

Abstract: A method for sensing objects within a rail grade crossing island is described. The method includes transmitting a radar signal into the island from each of a plurality of radar devices such that each portion of the island is monitored by at least two of the radar devices, detecting if an object is in the island based on received signals corresponding to the transmissions associated with at least one of the radar devices, and operating a gate control device associated with the rail grade crossing based on the detections.

Abstract: A high-precision distance measuring with a reduced error in a distance measuring system which calculates a distance from an arrival time of each pulse signal constituting a pulse sequence is provided. For an oscillator which generates pulse signals by counting the number of pulse signals constituting a received pulse sequence, a relative time difference between a transmitting device and a return device is acquired, a distance from the transmitting device to the return device is calculated, and the calculated distance is corrected based on the calculated relative time difference.

Abstract: A radar device including: a reception antenna that receives radio waves, includes at least three antennas and is arranged so that the phase center points thereof form an isosceles triangle; an arrival direction detection unit that detects an arrival direction of the radio waves by a phase monopulse method; and a phase correction unit that corrects a phase difference between phases of radio waves respectively received by two adjacent antennas among the three antennas based on the relationship of the phases of the radio waves respectively received by the three antennas.

Abstract: A method for estimating a radar cross-section (RES) of a given object by using a diffraction model of this object. With the model, it is possible to determine a basis adapted to said object on which is projected a vector of measurement. With the projected vector, it is possible to obtain a more complete reconstructed vector than the measurement vector in terms of incident wave and diffracted wave observation directions/polarizations and the components of which have a better signal/noise ratio than the measurements. The reconstructed vector is then used for calculating the RCS.

Abstract: A method and system for detecting RADAR signals in a radio communications system is provided. A detection system includes a pulse examination. Based on the result from the examination/analysis, a RADAR pulse is detected. The examination/analysis may include a correlator for correlating received pulses with themselves or samples previously obtained.

Abstract: Systems and methods for radar altimeter antenna performance monitoring via reflected power measurements are provided. In one embodiment, a single antenna radar altimeter comprises: an antenna; a circulator coupled to the antenna; a transmitter coupled to the circulator; a receiver coupled to the circulator; wherein the circulator provides coupling of the transmitter and the receiver to the antenna while providing isolation between the transmitter and the receiver; a reflected power monitor positioned between the circulator and receiver; and a processor coupled to the reflected power monitor via a first analog-to-digital converter, the processor configured to compute and track reflected power measurement statistics from data generated by the reflected power monitor and provide a performance output indicating when one or more of the reflected power measurement statistics exceed a predetermined deviation threshold.

Abstract: System that measures absolute or additive phase noise includes a power divider for dividing an input RF signal, a local oscillator, two mixers, each arranged in a path of a respective signal component from the power divider and receiving input from the power divider and local oscillator, two digital radio frequency memories, each associated with a respective mixer and receiving an input signal therefrom, and a digital signal processor that receives signals from the digital radio frequency memories and outputs a digital data stream indicative of measured phase noise. For absolute phase noise measurement, phase noise of the input RF signal is provided. For additive phase noise measurement, a unit under test is arranged in one of the paths between the power divider and the mixer. The system may be interposed between a radar transmitter of a radar environment simulator and a radar receiver coupled to a radar target display.

Abstract: Space-time coding is applied to a wave transmitter, receiver, or both. In general, the space-time coding is performed by real or synthetic motion of the transmitter or receiver, with the location of energy radiation/reception varying over the symbol duration with at least one occurrence during the symbol duration of a minimum instantaneous speed greater than a quarter of the ratio of the smallest wavelength of the waves divided by the symbol duration, and with coded acceleration of the modification of location to modify the velocity over the symbol duration.

Abstract: In a method for checking the functionality of a mixer, the mixer is supplied with a high-frequency signal and a high-frequency comparison signal in order to generate a baseband signal. The amplitude of the high-frequency signal is modified as a function of time. A direct-current voltage component of the baseband signal which is output by the mixer is analyzed to determine the functionality of the mixer.

Abstract: A radar, mounted on a vehicle, emits electromagnetic waves to a side area of a vehicle and receives reflected electromagnetic waves to detect a distance and a bearing of a physical object. A speed of the vehicle is detected. When the vehicle speed is greater than a predetermined value, it is determined whether multiple reflection occurs based on at least distances detected by the radar. If it is determined that the multiple reflection occurs, an axis deviation of the radar is determined based on a difference between the detected bearing of the multiple reflection waves and a reference bearing.

Abstract: A yaw angle error of a motion measurement system carried on an aircraft for navigation is estimated from Doppler radar images captured using the aircraft. At least two radar pulses aimed at respectively different physical locations in a targeted area are transmitted from a radar antenna carried on the aircraft. At least two Doppler radar images that respectively correspond to the at least two transmitted radar pulses are produced. These images are used to produce an estimate of the yaw angle error.

Abstract: A method for ray-tracing in a wideband Gbyte Gbps communication system includes deriving scattering distribution characteristics of reflected signals reflected on a reflection plane, analyzing amplitude distribution of the scattering distribution characteristics to distinguish a specular signal and a diffuse signal, and comparing signal amplitudes of the specular signal and the diffuse signal to calculate received power of the reflected signals according to a result of the comparing.

Abstract: A method of determining adequacy of acquisition includes: attempting to acquire a satellite signal from a satellite and decoding first satellite orbit data; and determining the adequacy of acquisition of the satellite signal by using the first satellite orbit data and second satellite orbit data that has been acquired from the satellite.

Abstract: Systems and methods for radar altimeter antenna performance monitoring via reflected power measurements are provided. In one embodiment, a single antenna radar altimeter comprises: an antenna; a circulator coupled to the antenna; a transmitter coupled to the circulator; a receiver coupled to the circulator; wherein the circulator provides coupling of the transmitter and the receiver to the antenna while providing isolation between the transmitter and the receiver; a reflected power monitor positioned between the circulator and receiver; and a processor coupled to the reflected power monitor via a first analog-to-digital converter, the processor configured to compute and track reflected power measurement statistics from data generated by the reflected power monitor and provide a performance output indicating when one or more of the reflected power measurement statistics exceed a predetermined deviation threshold.

Abstract: Methods of testing GNSS-based positioning systems in obstructed environments may include specifying a required accuracy threshold for use in determining a reference trajectory. One or more difficult areas of relatively poor or missing GNSS availability may be located within the obstructed environment. Positioning information may be established for first reference points outside the difficult areas. Subsequently, by surveying with respect to the first reference points, positioning information may be established for second reference points within the difficult areas. The first and second reference points may then be used to determine a true path associated with the reference trajectory.

Abstract: A method and a system for calibrating at least one antenna (1,1-1,3. 1,j). At least a first antenna (1,4) within a first antenna array (102) can be selected as a primary reference antenna. At least one antenna (4,3) that is not within the first antenna array can be selected as a secondary reference antenna. At least a first signal propagation characteristic (122) can be measured based on at least one signal wirelessly communicated between the primary reference antenna and the secondary reference antenna. At least a second signal propagation characteristic (118) can be measured based on at least one signal wirelessly communicated between the secondary reference antenna and at least a second antenna (1,2) within the first antenna array. At least a first calibration coefficient can be determined for the second antenna.

Abstract: Signal compensation systems and methods compensate an estimated range profile from a plurality of detected signal returns from a true range profile, wherein the signal returns correspond to an emitted stepped frequency pulse-train. An exemplary embodiment utilizes knowledge of the radar system design to identify locations, predict power levels, and suppress the contributions of stepped-frequency range sidelobes (ambiguous peaks) in the estimated range profile, resulting in a cleaner and more accurate radar display.

Abstract: In a method for adaptive calculation of pulse compression filter coefficients for a received signal in a radar installation, which received signal is evaluated with the aid of a complex pulse compression mismatch filter, a pulse compression filter coefficient set h(t) is calculated for an ideal theoretical received signal s(t) for a pulse compression mismatch filter, such that a pulse compression output signal results with a desired main lobe to side lobe ratio.

Abstract: An enhanced impulse response measurement for a pulsed frequency modulation (FM) radar signal provides a more accurate measurement of the amplitude of a secondary response relative to the amplitude of a main response. The pulsed FM radar signal is sampled to produce a time-domain sample record. The sample record is windowed to produce a windowed sample record. The windowed sample record is transformed into a frequency-domain spectrum. The spectrum is multiplied with the complex conjugate of a frequency-domain estimate of a transmitted pulsed FM radar signal to produce a de-spreaded pulse. The de-spreaded pulse is transformed into the time domain to produce a measurement of the impulse response having a main response and a secondary response. The amplitude of the secondary response is corrected to eliminate errors caused by the windowing.

Abstract: To depict test objects using electromagnetic waves, particularly to check people for suspicious articles, an apparatus is provided having: an antenna which emits electromagnetic waves, particularly millimetric waves, means for concentrating the emitted waves in three dimensions, and means for manipulating the waves at the point of high concentration such that this point serves as a moving virtual antenna for SAR evaluation. Whereby the means for three-dimensional concentration contain a rotatably mounted, focusing or defocusing, quasi-optical element and the means for manipulating the waves at the point of high concentration contain a reflector. In accordance with the invention, the quasi-optical element and the reflector are rotatably mounted about a common rotary axis and at the same angular velocity.

Abstract: There is provided an apparatus for capturing cosmic background radiation and for converting cosmic background radiation into electricity. An antenna is configured so as to capture cosmic background radiation. An electrostatic electron multiplier is connected to the antenna. A high voltage power supply is connected to the electrostatic electron multiplier whereby cosmic background radiation is converted to electricity.

Abstract: To suppress cross-ambiguities in the examination of an ice region or dry region by means of aircraft- or aerospace-supported radar echo sounding, the region to be examined is overflown by a radar sensor (6) by multiple compatible radar sensors of the same operating wavelength on multiple spatially separated, substantially parallel paths, wherein the radar signal data received on each path are recorded. The radar signal data recorded for each of the different paths are summed coherently and using a weighting to form a radargram, wherein an adaptive complex-valued weighting for each of the individual paths is performed using a geometrical model which takes into account the topography of the environment of the region to be examined. The weighting for every depth of the examined region is determined by solving a system of linear equations from which is calculated a synthetic antenna pattern which has zeros in the direction of the ambiguities.

Abstract: According to one embodiment, simulating the mutual performance of an antenna array coupled to an electrical drive circuit includes receiving one or more cross-coupling matrices and a number of electrical circuit parameters. Each cross-coupling matrix comprises matrix elements that each represent a cross-coupling factor of one antenna element to another antenna element of the antenna array. The electrical circuit parameters model one or more characteristics of the electrical drive circuit. Performance of the microwave antenna array and the electrical drive circuit in a far-field environment is modeled according to the electrical circuit parameters and the cross-coupling matrices.

Abstract: A radar sensor having a corresponding evaluation and control device, which has a measuring mode for locating radar targets and a blindness detection device, which is configured to detect blinding of the radar sensor with the aid of the signals received by the radar sensor itself; wherein the evaluation and control device has a test mode, in which the radar sensor is controlled on the basis of parameters that are different from the parameters for the measuring mode and optimized for the blindness detection device, and the evaluation and control device has a switching device for switching over between the measuring mode and the testing mode.

Abstract: A radar that detects the presence or absence of interference when detecting a target based on a frequency spectrum of a beat signal of a transmission signal and a reception signal. Whether or not the number of peaks exceeding a noise threshold in the frequency spectrum exceeds a predetermined number is determined. According to the determination result, the presence or absence of interference on the beat signal is detected. If “interference exists”, the threshold for extraction of target peaks that appear on the frequency spectrum is increased. This allows detection of the presence or absence of a spike noise superposed on the beat signal to be performed more certainly, thereby enabling processing according to the presence or absence of interference.

Abstract: A method of determining a deviation of a path of a projectile from a predetermined path. The method uses an image of a target area in which the desired path or direction is pointed out. Subsequently, the real direction or path is determined and the deviation determined.

Abstract: The present invention relates to antenna calibration for active phased array antennas. Specifically, the present invention relates to a built-in apparatus for autonomous antenna calibration. Accordingly, the present invention provides an antenna array comprising: a plurality of antenna elements forming an array face and a plurality of calibration antennas mounted around the array face. The plurality of calibration antennas comprising one or more pairs. The calibration antennas have overlapping coverage areas such that the entire array face of the antenna array is within the coverage area of at least one calibration antenna and each pair of calibration antennas have overlapping coverage areas such that of a common area of the array face is within both coverage areas.

Abstract: A method to improve a system's signal performance may comprise: generating a first signal, transmitting the first signal, receiving the first signal, and generating a second signal. The method may further comprise: identifying signal distortions generated by at least one of, a transmitter hardware that transmits the first signal and a receiver hardware that receives the first signal, modifying the second signal based upon the identified signal distortions, correlating the first signal and the second signal by a correlator to generate a correlated signal, and outputting the correlated signal.

Abstract: An array antenna has elements spaced less than one-half wavelength in order to produce a spatial pattern which has both visible and invisible regions. The elements in their nominal state are weighted so as to define particular sidelobe levels. In the presence of failed elements which might otherwise degrade the sidelobe levels, the element weighting function is compensated so as to preserve the sidelobe levels within the visible region of the antenna pattern by placing most or all of the degradation of the sidelobe levels into the invisible region of the antenna pattern.

Abstract: A method according to an aspect of the present invention includes determining a phase offset by simultaneously providing a calibration signal to a first element of an antenna and a second element of the antenna opposite the first element. The method further includes receiving an intermix signal by a third element of the antenna, measuring an amplitude characteristic for the intermix signal, and determining a phase offset based on the amplitude characteristic. The phase offset can be used to adjust a signal provided to the first element so that signals transmitted from the first element and second element are in phase with each other. This method can account for phase errors due to the construction or design of the antenna, and allows antenna elements to be calibrated without the need for phase detector devices.

Abstract: A method for determining a phase constant for a dielectric medium is provided. The method includes deploying a calibration object with a known free-space spectral response within a dielectric medium of interest, determining the spectral response of the calibration object deployed in the dielectric medium, and determining the phase constant for the dielectric medium using a relationship between the free-space spectral response of the calibration object and the spectral response of the calibration object when deployed in the dielectric medium.

Abstract: A method for determining whether a target of interest located within radar resolution cells in a target area of interest is detectable with a radar system from a location and elevation of the radar system is described. The method includes the steps of (a) developing a topographic map of the terrain in the target area of interest; (b) mapping the radar resolution cells onto the topographic map; (c) modeling radar signal propagation to each of the radar resolution cells on the topographic map; and (d) determining, using the results of the modeling, if the radar system has sufficient signal-to-noise (SNR) to detect the target of interest.

Abstract: A level verification system for a radar level gauge utilizes a remotely positionable target. The target is positioned inside of a tank that is subject to level measurement, and stowed at a first position and selectively positionable to a second position to reflect emitted electromagnetic radiation in an amount indicative of a predetermined material level. The verification system can verify a high level alarm will be triggered when the material reaches a high level corresponding to the level of the target, by remotely positioning the target in front of the emitter of the radar gauge. The target reflects electromagnetic energy to the detector at approximately the same intensity that the material reaching the high level would reflect so as to provide an accurate verification.

Abstract: A calibration system for the receiver of a dual polarization radar system has been developed. The system includes a radar transmitter that transmits signals in horizontal and vertical polarizations and a radar receiver that receives the horizontal and vertical polarization signals. The system also includes a test signal generator that generates a continuous wave test signal. A calibration circuit for the radar receiver modifies the test signal to simulate weather conditions by adjusting the attenuation and Doppler phase shift of a continuous wave test signal.

Abstract: The present invention relates to antenna calibration for active phased array antennas. Specifically, the present invention relates to a built in apparatus for autonomous antenna calibration Accordingly, the present invention provides a method of calibrating an antenna array comprising the steps of: (i) loading a set of correction coefficients for all or a portion of the antenna array; (ii) outputting a known test signal from all or a portion of the antenna array using said correction coefficients; (iii) measuring the performance of all or a portion of the antenna array using a plurality of calibration antennas; and (iv) generating a new set of correction coefficients to correct the performance of all or a portion of the antenna array.

Abstract: The present invention relates to antenna calibration for active phased array antennas. Specifically, the present invention relates to a built in apparatus for autonomous antenna calibration Accordingly, the present invention provides a method of continuous on-line monitoring of each element in an array antenna comprising the steps of: (i) transmitting known test signals to one or more elements of the array antenna; (ii) monitoring responses of the elements to the test signals; and (iii)comparing the response with expected responses for the elements to determine an operation condition of the elements.

Abstract: A system for estimating an antenna boresight direction. The novel system includes a first circuit for receiving a Doppler measurement and a line-of-sight direction measurement corresponding with the Doppler measurement, and a processor adapted to search for an estimated boresight direction that minimizes a Doppler error between the Doppler measurement and a calculated Doppler calculated from the estimated boresight direction and the line-of-sight direction measurement. The line-of-sight direction measurement is measured relative to the true antenna boresight, and the calculated Doppler is the Doppler calculated for a direction found by applying the line-of-sight direction measurement to the estimated boresight direction. In a preferred embodiment, the first circuit receives a Doppler measurement and a line-of-sight direction measurement from each of a plurality of pixels, and the processor searches for an estimated boresight direction that minimizes a sum of squares of Doppler errors for each of the pixels.

Abstract: An antenna method and system to implement a quasi-compact range technique/technology in which a reflector antenna is used to produce a test field within a test region at a quasi-compact range, which is within a near-field of the reflector antenna but further from the reflector antenna than a compact range of the reflector antenna.

Abstract: Systems and methods for testing a signal generated by a Direct Digital Synthesizer (DDS) in a radar altimeter. In an embodiment of the method, a voltage signal derived by comparing a fixed reference frequency to a ramped frequency signal generated by the DDS based on a clock-based reference signal is generated. The generated voltage signal is integrated over a predefined range of clock signals. The integration is sampled at a previously defined clock tick. The sample is compared to a desired value and an indication that the radar altimeter is malfunctioning is provided if the comparison exceeds a predefined threshold value. The radar altimeter system is deactivated if an indication that the radar altimeter is malfunctioning has been provided.

Abstract: A method for main beam alignment verification includes providing data pertaining to one or more patterns associated with an antenna, measuring power levels of a signal acquired by the antenna, and comparing the measured power levels with the data to determine whether a direction of the signal is incident upon a main beam of the antenna.