Abstract: A small cell (e.g., femtocell) in a wireless communication may determine a set of wireless signal measurements for a plurality of small cells causing pilot cell pollution within a coverage area. The small cell may determine an adjustment of a transmission parameter of the small cells for reducing the pilot cell pollution, and transmit the adjustment to the small cells. The adjustment may include, for example, minimizing an area of overlap between at least two small cells having signal power difference below a threshold, maximizing a signal to interference and noise ratio at a location associated with at least two small cells, minimizing an area associated with at least two pilot signals within a threshold signal level, distributing traffic load to at least two of the small cells based on the set of measurements, or by minimizing the number of small cells covering a path.

Abstract: A mobile communications device may include an RF signal source configured to generate RF signals over an RF frequency band(s), and an RF transmitter coupled to the RF signal source. The RF transmitter may include an RF amplifier configured to operate over a plurality of different power control levels. The RF amplifier may have an input configured to receive the RF signals from the RF signal source and an output having an impedance which changes based upon changes between the different power control levels. The RF transmitter may further include a shunt resistor(s) coupling the output of the amplifier to a voltage reference, and the shunt resistor(s) may be configured to decrease a highest impedance change of the RF amplifier output to below a threshold impedance level. An antenna(s) may be coupled to the output of the RF amplifier to operate over the at least one RF frequency band.

Abstract: The relative position of one vehicle vs. another vehicle, both driving in a vehicular environment, is determined using vehicular communications based on the IEEE 802.11 standard. The relative position determination is performed in a measuring vehicle using data provided by a measured vehicle through IEEE 802.11 communications carried through beacons as well as GPS or other location data and local map information.

Abstract: A driving assist apparatus for a vehicle is disclosed. The driving assist apparatus includes a transmitter for transmitting a transmission wave, a receiver for receiving a reflected wave, an obstacle presence determination section for detecting a presence of an obstacle in the surrounding of the vehicle based on the reflected wave, a measurement section for measuring a frequency of phase delay and advance of the reflected wave with respect to a reference signal, and a detection section for detecting the obstacle having a specific relation with the vehicle based on the presence of the obstacle determined by the obstacle presence determination section and the frequency of delay and the frequency of advance measured by the measurement section.

Abstract: A system, method, and apparatus for radar pulse detection using a digital radar receiver are disclosed herein. In electronic warfare (EW), radars operate in an environment with highly dense electronic waveforms. As a result, the radars may receive thousands or millions of radar pulses every second. To detect and sort out radar pulses emitted from different radars is a challenging problem in electronic warfare. The present disclosure teaches a radar pulse detection system that utilizes digital channelization and joint-channel detection techniques to detect and separate radar pulses that are sent from different radar emitters. The main features of the present disclosure are: 1.) a digital channelization technique to separate radar pulses from their mixtures; 2.) a multi-channel detection technique to detect radar pulses; and 3.) an innovative technique to separate overlapped radar pulses.

Abstract: A D/A conversion circuit in accordance with the present invention, which is provided with a switch swD, allows a writing operation of a voltage (a true gradation voltage) to be performed at a higher speed by first applying a first voltage (a voltage close to the true gradation voltage), which is supplied without passing through a resistor element, to an output line and then applying a second voltage (the true gradation voltage), which is supplied via the resistor element, to the output line. Thus, the present invention can provide a D/A conversion circuit capable of writing display data to liquid crystal cells with higher precision at higher speed, and a semiconductor device utilizing such a D/A conversion circuit.

Abstract: Aspects of this invention are directed to the substantially improved detection and geolocation accuracy of targets (stationary or moving) by using the coherent data received at multiple airborne sensors. Further aspects are directed to aligning the (unknown) time-delayed and Doppler-shifted signals received at the multiple sensors relative to an arbitrary reference sensor, which depend on the unknown target position. This results in the target position and velocity vectors being simultaneously estimated and the detection peak enhanced by obtaining near coherent gain. Still further aspects are directed to the coherent generalized likelihood ratio test (GLRT) and the minimum variance distortionless response (MVDR) statistic for multistatic radar systems, conditioned on estimation of certain parameters that render the system coherent. Analytical and computer simulation results are presented to show substantially enhanced detection and geolocation of moving targets in clutter.

Abstract: A system includes a first clock module, a global positioning system (GPS) module, a phase-locked loop (PLL) module, a cellular transceiver, and a baseband module. The first clock module generates a first clock reference. The GPS module operates in response to the first clock reference. The WLAN module operates in response to the first clock reference. The PLL module generates a second clock reference by performing automatic frequency correction (AFC) on the first clock reference in response to an AFC signal. The cellular transceiver receives radio frequency signals from a wireless medium and generates baseband signals in response to the received radio frequency signals. The baseband module receives the baseband signals, operates in response to a selected one of the first clock reference and the second clock reference, and generates the AFC signal in response to the baseband signals.

Abstract: A method of detecting movement includes using a radar sensor to monitor a space, and receiving an output signal from the radar sensor. A Fourier transform is performed on the output signal to produce a frequency domain signal spectrum. The frequency domain signal spectrum is transformed into an acoustic domain signal. It is decided whether the output signal is indicative of movement of a predetermined object or a non-human animal dependent upon at least one feature of the acoustic domain signal and at least one spectral feature of the signal spectrum.

Abstract: The relative position of one vehicle vs. another vehicle, both driving in a vehicular environment, is determined using vehicular communications based on the IEEE 802.11 standard. The relative position determination is performed in a measuring vehicle using data provided by a measured vehicle through IEEE 802.11 communications carried through beacons as well as GPS or other location data and local map information.

Abstract: A method for measuring certain parameters of the impulse response of a propagation channel involving emitters and reflectors that are fixed or mobile, and for detecting and determining the parameters regarding the position and kinematics of the emitters and reflectors, or for auto-locating the reception system implementing the invention, in a system comprising N sensors receiving signals from the emitters or from the reflection on the reflectors. The method determines an ambiguity function which couples the spatial analysis and the delay-distance/Doppler-kinematic analysis, and determines at least one sufficient statistic ?(l,m,K) corresponding to the correlation between the known signal s(kTe) corresponding to the complex envelope of the signal emitted and the output of a filter w(l,m) where l corresponds to a temporal assumption and m corresponds to a frequency assumption.

Abstract: A system includes a first clock module, a global positioning system (GPS) module, a phase-locked loop (PLL) module, a cellular transceiver, and a baseband module. The first clock module generates a first clock reference. The GPS module operates in response to the first clock reference. The WLAN module operates in response to the first clock reference. The PLL module generates a second clock reference by performing automatic frequency correction (AFC) on the first clock reference in response to an AFC signal. The cellular transceiver receives radio frequency signals from a wireless medium and generates baseband signals in response to the received radio frequency signals. The baseband module receives the baseband signals, operates in response to a selected one of the first clock reference and the second clock reference, and generates the AFC signal in response to the baseband signals.

Abstract: A system comprises a first clock module configured to generate a first clock reference that is not corrected using automatic frequency correction (AFC). A global position system (GPS) module is configured to receive the first clock reference. An integrated circuit for a cellular transceiver includes a system phase lock loop configured to receive the first clock reference, to perform AFC, and to generate a second clock reference that is AFC corrected.

Abstract: A method is provided for coordinating detection of emitted signals by a receiver with transmission of signals by a transmitter, wherein the receiver and the transmitter are located on the same platform. The receiver scans a surrounding environment to detect emitted signals in multiple frequency ranges while the transmitter transmits signals in a predetermined frequency range. The receiver may employ dwells which may be defined as receiver configurations. A dwell, when executed, may be used to detect signals in a certain frequency range. If a frequency range of the dwell conflicts with the frequency range of transmitter signals, which may result in interference of transmitter signals with detection of emitted signals, execution of the dwell may be delayed. If the frequency range of the dwell is such that transmitter signals do not interfere with execution of the dwell, the dwell can be executed.

Abstract: The invention provides a method for identification of traffic lane boundary. Firstly the microwave signal is received, and the noise reduction is treated for the microwave signal. Then the frequency domain information is employed to calculate the legal set of closed interval, in order to form the frequency span information. Finally, the probability density function model is employed to calculate the frequency span information in order to identify the traffic lane boundary.

Abstract: A method and apparatus is disclosed to recover at least one information payload from a frame and/or to configure one or more reception parameters to receive a future frame to support RIFS. A physical layer device (PHY) receives at least a training sequence embedded in the frame of a transmitted communication signal using a receiver filter bandwidth corresponding to a variable filter training sequence bandwidth. The PHY determines an amount of gain necessary to recover an information payload embedded in the frame based on the recovery of the training sequence. The PHY determines an amount of gain necessary to recover an information payload embedded in the frame based on the recovery of the preamble. A previous communications receiver gain is adjusted by the difference between the amount of gain necessary to recover the information payload and the previous communications receiver gain.

Abstract: An ultra wide band (UWB) millimeter (mm) wave radar system includes a signal source having a control input, a GHz signal output and a frequency controlled output. A control loop is coupled between the GHz signal output and the control input including a frequency divider and a digitally controlled PLL that provides a locked output coupled to the control input of the signal source to provide frequency locked output signals that are discrete frequency swept or hopped. A frequency multiplier is coupled to the frequency controlled output of the signal source for outputting a plurality of mm-wave frequencies. An antenna transmits the mm-wave frequencies to a surface to be interrogated and receives reflected mm-wave signals therefrom. A mixer mixes the reflected mm-wave signals and mm-wave frequencies and processing circuitry determines at least one parameter relating to the surface from the mixing output.

Abstract: A target is sensed by an antenna array having a transmitter antenna and a receiver antenna, both of which are caused to be electromagnetically coupled to the target. The antenna array is rotated, and as the array rotates, a change in at least one of the coupling between the transmitter antenna and the target and the coupling between the receiver antenna and the target is detected at multiple rotational orientations of the antenna array.

Abstract: The array antenna includes a feed line, and a plurality of radiating element sections arranged at a predetermined arranging interval in a first direction, each of the radiating element sections including at least one radiating element fed a traveling wave through the feed line. The inter-element line length as a length of the feed line between each succeeding two of the radiating element sections is longer than the arranging interval in the first direction.

Abstract: A method of processing an input signal to perform frequency analysis is disclosed. The input signal comprises a desired signal and an interference signal. A crosslation is performed to generate a representation of the frequency content of the input signal. The representation comprises initial crosslation values predominantly corresponding to interference and subsequent crosslation values corresponding to the desired signal. For the crosslation values corresponding to interference, a maximum value and slope are calculated. These are used as parameter indicators of the interference and also to identify which values should be discarded in the processing of the desired signal. With the crosslation values corresponding to interference discarded, the remaining crosslation values are processed to calculate properties of the desired signal.

Abstract: A D/A conversion circuit in accordance with the present invention, which is provided with a switch swD, allows a writing operation of a voltage (a true gradation voltage) to be performed at a higher speed by first applying a first voltage (a voltage close to the true gradation voltage), which is supplied without passing through a resistor element, to an output line and then applying a second voltage (the true gradation voltage), which is supplied via the resistor element, to the output line. Thus, the present invention can provide a D/A conversion circuit capable of writing display data to liquid crystal cells with higher precision at higher speed, and a semiconductor device utilizing such a D/A conversion circuit.

Abstract: A millimetric wave imaging device includes: a lens antenna; a polygon mirror; a receiving portion; a scanning unit; and an image data generating unit. The receiving portion receives millimetric wave radiated from an object, transmitted through the lens antenna, and reflected on a mirror surface of the polygon mirror rotated by the scanning unit to detect a signal level of the millimetric wave. The image data generating unit generates image data representing an object image by receiving a detection signal from the receiving portion while driving the polygon mirror through the scanning unit.

Abstract: The portion corresponding to a main bang signal leaking from a transmission/reception switching unit is extracted as a frequency estimation signal from an IF signal from a mixer in a signal extracting unit, a frequency is estimated in a frequency estimating unit, and the frequency of a local oscillation signal of a local oscillator is controlled so that the frequency of the IF signal is equal to a target value. The frequency estimation in the frequency estimating unit is carried out by using Discrete Fourier Transform or Fast Fourier Transform.

Abstract: A radar detector is operated to suppress nuisance radar alerts by identifying a first signal in radar band of interest, e.g., having a frequency that is a harmonic of a first nuisance local oscillator frequency leaked from a nearby radar detector and identifying a second signal having a frequency that is a harmonic of a second nuisance local oscillator frequency leaked from the radar detector where the first and second local oscillators are companion signals. A detector is also provided that suppresses nuisance radar alerts by detecting a first signal in a radar band, providing a first alert designating the detection of the first signal, determining that the first signal is a nuisance signal, providing a second alert designating that the first signal is a false alarm, and turning off the second alert after a predetermined period.

Abstract: A D/A conversion circuit in accordance with the present invention, which is provided with a switch swD, allows a writing operation of a voltage (a true gradation voltage) to be performed at a higher speed by first applying a first voltage (a voltage close to the true gradation voltage), which is supplied without passing through a resistor element, to an output line and then applying a second voltage (the true gradation voltage), which is supplied via the resistor element, to the output line. Thus, the present invention can provide a D/A conversion circuit capable of writing display data to liquid crystal cells with higher precision at higher speed, and a semiconductor device utilizing such a D/A conversion circuit.

Abstract: The present disclosure relates to a radar device and technique for detecting the presence of objects located in the near-field of a frequency modulated, continuous wave (FMCW) radar device. The technique includes transmitting and receiving a frequency modulated signal, generating an intermediate frequency signal based on the transmitted and received signals, and analyzing the frequency content of the intermediate frequency signal. The frequency content of the intermediate signal is analyzed without filtering out a carrier signal.

Abstract: A method for receiving at least one signal emitted by at least one emitter includes defining a first dwell associated with a first signal. The first dwell has a frequency range that overlaps at least a portion of a frequency range of a second signal. The method also includes detecting the second signal responsive to the first dwell if the first dwell satisfies at least one criterion for detecting the second signal. The method further includes rejecting the second signal responsive to a characteristic of the second signal if the first dwell fails to satisfy the at least one criterion.

Abstract: A system and method is provided for detecting emitter signals and for determining a scan strategy for a receiver system that receives such emitter signals. A rule-based system is provided for determining how emitters should be detected by a detection system. Rules may be used to prioritize certain emitters with respect to other emitters. The rules may also specify parameters for emitter modes, such as probability of intercept, turn-on range, detect-by range, tolerance, tolerance direction, scan periods, and other parameters. The rules may be used to compute the revisit time for the receiver. Multiple sets of rules may be created and a scan strategy may be computed based upon the selected rule set.

Abstract: A system and method is provided for detecting emitter signals and for determining a scan strategy for a receiver system that receives such emitter signals. In one embodiment, the scan strategy may be computed to operate in a manner cognizant of on-board active jammers, optimizing the jammer band and intercept band performance. The additional inputs for this task are a jammer band assignment table, and a blanking assignment table. The capability to generate “dry” (no jam) and “wet” (jamming) scan strategies for an emitter set is provided, with separate intercept rules for each.

Abstract: An arrangement for reducing the effect of vibration-induced changes in phase of the first local oscillator in a tracking receiver wherein final detection is accomplished by a synchronous detector in a phase lock loop incorporating a voltage-controlled oscillator is shown to include a differentiator providing a control signal whenever a vibration-induced change occurs, such control signal being applied to cause the time taken for the voltage-controlled oscillator to regain proper phase is reduced to a minimum.

Abstract: The present invention is directed to a system and method for Doppler track correlation for debris tracking in PCL radar applications. The disclosed embodiments describe the systems and methods used in the detection of debris pieces and the association of the Doppler signals from the debris pieces across multiple illumination channels. The present invention also provides computation of debris state vectors and the projection of trajectories to determine debris impact points.

Abstract: An HF radar system comprises a transmitting system, a receiving system, a signal processing system and a frequency management/ionospheric sounding system. The transmitting system comprises a transmitting antenna array configured to transmit a beam in a near vertical direction and a transmitting device arranged to drive the transmitting antenna array at frequencies suitable for downward refraction by the ionosphere. The receiving system comprises a receiving antenna array configured to receive returning signals from a target area returning to the receiving antenna array via refraction at the ionosphere. The signal processing system comprises a digital data processing system. The frequency management/sounding system comprises cooperating transmitting and receiving systems sending HF signals to the ionosphere and analysing the returning signals. Alternatively, the system may have a duplexed antenna array.

Abstract: An average power value of a peak pair corresponding to a subjective target objective is converted into a radar cross section, to calculate a normalized average power value NP and a standard deviation DP representing a temporal dispersion of a power difference between peak pairs. When the value NP is larger than an automotive vehicle discriminating threshold THnp, the attribute of the subjective target objective is set to “automotive vehicle.” When the value NP is not larger than the threshold THnp and the deviation DP is larger than a human objective discriminating threshold THdp, the attribute of the subjective target objective is set to “non-vehicle objective: human objective.” Furthermore, when the value NP is not larger than the threshold THnp and the deviation DP is not larger than the threshold THdp, the attribute of the subjective target objective is set to “non-vehicle objective: non-human.

Abstract: A method of recognizing a radar target comprises producing a sequence of Doppler spectra of radar returns form a scene and producing therefrom a sequence of Doppler feature vectors for a target in the scene. Hidden Markov modelling (HMM) is then used to identify the sequence of Doppler feature vectors as indicating a member of a particular class of targets. HMM is used to identify the sequence of Doppler feature vectors by assigning to each feature vector an occurrence probability by selecting a probability distribution or state from a set thereof associated with a class of targets, multiplying the occurrence probabilities together to obtain an overall probability, repeating for other probability distributions in the set to determine a combination of probability distributions giving highest overall probability for that class of target, then repeating for at least one other class of targets and selecting the target class as being that which yields the highest overall occurrence probability.

Abstract: A transmitted signal and a received signal are combined and the combination is expected to determine whether or not a target signal is present. Either the transmitted signal or the received signal is combined with an auxiliary signal containing a range of frequencies corresponding to an anticipated Doppler shift, so that an output of the combined transmitted and received signal will be present only if a target signal exhibiting a Doppler shift within the anticipated range is present. The auxiliary signal preferably comprises finite-duration signal portions of different types so as to provide a substantially uniform frequency response throughout the selected range.

Abstract: Embodiments of the present invention are directed to a method and apparatus for substituting temperature sensor data for a satellite signal in a GPS receiver. In one embodiment of the present invention, a mathematical model of a GPS receiver's clock's response to temperature change is maintained. In one embodiment, the mathematical model is a third order polynomial. In one embodiment, when a GPS receiver has contact with at least four GPS satellites, the receiver collects data on changes in temperature and resulting changes in the GPS receiver's clock frequency. The data is incorporated into the GPS receiver's mathematical model. In one embodiment, the data is incorporated by modifying one or more coefficients in the mathematical model. In one embodiment, if a GPS receiver only has contact with three GPS satellites, changes in temperature and the mathematical model are used to estimate an adjustment to the signal generated by the clock.

Abstract: In a method for the determination of the unambiguous range for the measurement of the IF deviation in a frequency-regulated radar system, a frequency adjustment or tuning of the radar system is carried out during the reception of an echo signal by adjustingly setting respectively at least one value for the IF deviation around the value zero in the unambiguous range of the IF deviation as well as in an ambiguous range of the IF deviation. Then, the unambiguous range is recognized as such by comparison of the signal amplitude and/or the number of the detected targets during these adjustment settings, because the unambiguous range exhibits the highest signal amplitude and/or the greatest number of detected targets (i.e. echo signals).

Abstract: A radar system receiver having an antenna system adapted to receive a jammer signal from both a direct path and from an indirect path. The direct and indirect paths have both differential Doppler frequency and differential time delay induced phase shifts. The antenna system includes a plurality of antenna elements. A plurality of radar receiver sections, each one having a clutter filter, is provided. Each one of the receiver sections is fed by a corresponding one of the antenna elements. An adaptive jammer canceler is fed by the plurality of radar receiver sections for providing a beam forming network to suppress both the direct and indirect paths of the jamming signal.

Abstract: A radar signal detecting apparatus is provided. The radar signal detecting apparatus includes a coupler diverging a part of signal from received signal, a local oscillator outputting local signal, a mixer converting the diverged signal multiplied the local signal into low frequency signal and a detector detecting, a radar signal from the low frequency signal by using a threshold above side lobe.

Abstract: A ground penetrating radar comprises a signal generator, a return signal processor, gating means and antenna. The signal generator is a dual frequency synthesiser that generates a stepped frequency master signal and a tracking signal offset by an intermediate frequency. The return signal processor is a dual channel quadrature receiver that mixes down a return signal and a sample of the master signal to intermediate frequency using the tracking signal. The signal generator is pulsed by the gating means and the return signal is gated at the same frequency. Hollow pyramidal antennas are also described that have an ultrawide band bowtie structure with antenna electronics located within one antenna element. A method of operating the radar is also described.

Abstract: A system for determining the scan type of a signal, such as a radar signal, includes a scan detector, a transformer (e.g., an FFT algorithm), a correlator, and a decision block. The signal is received and processed by the scan detector. The scan detector provides an envelope signal, representing the scan type of the received signal. The envelope signal is transformed, typically from a time domain signal to a frequency domain signal, by any of several processes including a Fourier transform, a Laplace transform, an FFT, or a DFT. The transformed envelope signal is compared to several scan data sets by the correlator. Each scan data set represents a particular scan type. If the decision block determines that the comparison between the transformed envelope signal and a scan data set meets (or exceeds) a degree of similarity, the scan type of the received signal is determined to be the scan type of that scan data set.

Abstract: The pulse center detector (PCD) produces an amplitude-independent center-triggered range output for precision radar rangefinders and TDR systems. Pulse center triggering is accomplished by triggering leading-edge and trailing-edge detectors and summing the outputs to produce a computed center-triggered result. Since the occurrence time of a pulse center does not vary with amplitude, the PCD is amplitude-independent. The PCD overcomes limitations of prior automatic pulse detectors, such as the inherent latency of a constant fraction discriminator (CFD) and the uncertainty of a time-of-peak (TOP) detector. The PCD can be implemented with a single analog component—a comparator—and thus requires appreciably fewer analog components than prior automatic detectors while providing lower jitter. Applications include radar and TDR tank gauges, and radar rangefinders for robotics and automotive applications.

Abstract: An arrangement for the precise measuring of the distance with a FMCW radar device having a frequency-variable digitally-actuated oscillator to generate a transmitting frequency which can be tuned over a predetermined frequency range. The digital actuation involves the use of a digital frequency generator which derives in predetermined frequency steps a references signal from a fixed-frequency oscillator signal. The frequency of the frequency-variable oscillator is adjusted in a phase-locked loop linking it to the references signal.

Abstract: A radio frequency identification system includes a transponder and a transponder reader. The transponder, responsive to an interrogation signal continuously transmitted by the transponder reader, generates a transponder signal modulated by an identification signal readable by the transponder reader. The identification signal includes a synchronization portion, a data portion, an output format identification portion, and an error detection portion. The output format identification portion is used by the reader to configure itself for communication with an attached controller. In another aspect of the invention, the transponder reader may be configured to read FSK as well as PSK encoded signals from the transponder.

Abstract: This invention concerns a procedure for the elimination of interferences, such as pulses and linear chirps, in a radar unit of the FMCW type According to the procedure, the useable signal in the form of a beat signal, is subjected to time-frequency division of the type STFT for division of the signal into narrow-band frequency bands. Interference is detected and eliminated in each frequency band, after which the time signal freed from interference and its Discrete Fourier Transform, DFT, are calculated from the time-frequency division in narrow-band frequency bands.

Abstract: An electronic counter-measure receiver can be colocated with a threat simulator radar, which transmits a radar signal. As a pulsed-Doppler signal, this transmitted radar signal is sampled as a reference signal by the receiver to determine quadrature, coherent matched filter coefficients. A return signal is received and processed with the reference signal as quadrature signal components with the quadrature, coherent matched filter coefficients within a matched filter. The return signal is processed as a first intermediate frequency via a mixer and local oscillator and a second quadrature intermediate frequency via a digital local oscillator and mixer. A fast Fourier transform is performed to determine Doppler information. In a continuous wave transmission for sampling arbitrary but unevenly spaced in time pulses are generated from a pulse generator source internal to the receiver.

Abstract: A radar receiver adapted to detect and track a narrow band jammer is shown to include logic circuitry adapted successively to sense jamming signals from such a jammer to determine the extant frequency of the speed gate when the amplitude of the automatic gain control signal increases and to determine whether or not the received signals are coherent, and, finally, if the received signals are not coherent, to produce a tracking control signal effective to cause tracking of the narrow band jammer.

Abstract: A circuit for use in anti-radar missile seekers or radar counter-measure eivers to convert the signals received from continuous wave radars into pulse signals so that the signals may be more readily detected and can be processed in the same signal processing circuitry used against pulse radars. The received signal is mixed with a frequency swept local oscillator signal, fed to a dispersive delay line and then detected.

Abstract: A method and apparatus for determining from a moving observer the location, in terms of latitude, longitude, altitude, and velocity, of a stationary or moving radar emitting a pulsed or continuous-wave signal. The moving observer extracts from the radar signal significant electronic support measures (ESM) parameters, including frequency, pulse repetition interval, and pulse width, and determines from those parameters whether a radio frequency (RF) or pulse repetition frequency (PRF) measurement technique is appropriate, and whether the radar signal angle-of-arrival (AOA) must be computed. The emitter location is computed using a ratio of sequential frequency measurements, and the moving observer continues to collect frequency measurements until the location of the emitter can be established to within a predetermined degree of certainty.

Abstract: A narrow bandwidth (1 to >100 MHz) HTS microwave filter (30 or 50) is described which is tunable over a moderate frequency range (100 to >1000 MHz at X-band). The low loss (<1 dB) and GHz/microsecond tuning rates enable the filter to operate as a radar preselector filter. The filter consists of a multi-pole microstrip or stripline HTS coupled one-half resonator pattern deposited onto a ferrite substrate (32 or 52, 54). The ferrite substrate is operated in a latching mode like that in the operation of digital phase shifters. The filter tunability arises from the variation of the effective permeability with the remanent magnetization.