Abstract: A bistatic radar system having a transmitter that generates unique signals at spatially independent transmitter degrees of freedom and a receiver that filters the signal at each receiver degree of freedom into a group of signals identical in number to the number of transmitter degrees of freedom. The receiver formats the filtered signals into a 2-dimensional array of elements. The receiver rotates the array so that the new axes are aligned with the Doppler gradient. The data is then re-sampled and projected to linearize the clutter signal. The receiver may be integrated with a broad class of adaptive and non-adaptive clutter mitigation approaches such as electronic clutter tuning and projected bistatic space-time adaptive processing, or STAP.

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 method according to an aspect of the invention is for filtering coherent multipulse radar, sonar or lidar returns. The method comprises the steps of separating the returns into mutually orthogonal I & Q components, performing wavelet processing on the I and Q components to generate an I & Q wavelet filter output. The I & Q wavelet filter outputs are data compressed to remove clutter portions. Data compression may be removal of large-amplitude or earliest wavelet responses. An inverse wavelet filtering function is performed on the compressed wavelet filter outputs, to thereby generate edited coherent I & Q components. Doppler filtering, is performed on the edited coherent I and Q components to thereby generate frequency-domain target data in which the minimum discernible target velocity is improved.

Abstract: A method and apparatus to remove human features utilizing at least one transmitter transmitting a signal between 200 MHz and 1 THz, the signal having at least one characteristic of elliptical polarization, and at least one receiver receiving the reflection of the signal from the transmitter. A plurality of such receivers and transmitters are arranged together in an array which is in turn mounted to a scanner, allowing the array to be passed adjacent to the surface of the item being imaged while the transmitter is transmitting electromagnetic radiation. The array is passed adjacent to the surface of the item, such as a human being, that is being imaged. The portions of the received signals wherein the polarity of the characteristic has been reversed and those portions of the received signal wherein the polarity of the characteristic has not been reversed are identified. An image of the item from those portions of the received signal wherein the polarity of the characteristic was not reversed is then created.

Abstract: A system and method for classifying radar emitters includes: (a) receiving a plurality of signals from the radar emitters; (b) generating data components for each signal received from the radar emitters; (c) forming multi-dimensional samples using the generated data components; and (d) sorting the multi-dimensional samples into a plurality of data clusters, based on their respective proximity to the data clusters, each data cluster representing a classification of a radar emitter.

Abstract: An FM-CW radar detects at least one of the relative distance and the relative speed of a predetermined object based on the frequencies of projection portions observed in the frequency spectrums of beat signals in an ascending-modulation section and a descending-modulation section, where the projection portions are generated by one and the same object. The radar determines the moving speed of a predetermined moving object such as a vehicle or the like having the radar mounted thereon, and the frequency difference between the projection portions observed in the frequency spectrums of the beat signals in the ascending-modulation section and the descending-modulation section is inversely calculated, where the frequency difference corresponds to the stationary object, and a predetermined pair corresponding to the frequency difference is extracted on a priority basis.

Abstract: An apparatus for identifying a buried object using ground penetrating radar (GPR) in a system containing at least one GPR sensor, comprises a data processor for detecting spatial correlations in data received from a GPR sensor in the apparatus and an image processor capable of building a data structure corresponding to an image of the buried object from data processed by the data processor. A method for identifying a buried object using GPR in a system containing a GPR sensor comprising detecting spatial correlations in data received from the GPR sensor in the system and building a data structure corresponding to an image of the buried object from the received data.

Abstract: A plurality of sensor vehicles collect imaging data from an assigned location of a target region having targets and non-targets. The imaging data may be combined based on its location and the combined data is matched to a threat object map to identify the actual targets from the non-targets. In some embodiments, the sensor vehicles may be redirected to collect velocity and/or range information on the identified targets.

Abstract: A first Kalman filter estimates true measures of yaw rate and vehicle speed from associated noisy measures thereof generated by respective sensors in a host vehicle, and a second Kalman filter estimates therefrom parameters of a clothoid model of road curvature. Measures of range, range rate, and azimuth angle from a target state estimation subsystem, e.g. a radar system, are processed by an extended Kalman filter to provide an unconstrained estimate of the state of a target vehicle. Associated road constrained target state estimates are generated for one or more roadway lanes, and are compared—either individually or in combination—with the unconstrained estimate. If a constrained target state estimate corresponds to the unconstrained estimate, then the state of the target vehicle is generated by fusing the unconstrained and constrained estimates; and otherwise is given by the unconstrained estimate alone.

Abstract: The invention relates to a radar device for measuring a relative distance to a target. It is an object of the invention to precisely determine the relative distance to the target in a wide range. The radar device according to the invention generates a second pulse by demodulating a signal arriving from a target as a response to a wave signal modulated with a first pulse. The radar device evaluates, as the relative distance to the target, such two different instances that an absolute value of a deviation of a ratio of two instantaneous values of the second pulse from a reference value as a ratio of two instantaneous values of the first pulse is to be minimum. The respective two instantaneous values are with a predetermined interval therebetween on a time axis.

Abstract: A multiple model (MM) radar tracking filter which controls the weighting applied to outputs of first and second model functions responsive to non-Markovian switching logic, includes the first and second model functions, switching logic receiving unweighted outputs from the first and second model functions and generating first and second weighting signals, first and second multipliers generating respective first and second weighted output signals responsive to received ones of the unweighted outputs of the first and second model functions and the first and second weighting signals, and a feed back loop for providing a feedback signal to respective inputs of the first and second model functions responsive to the weighted outputs of the first and second multipliers. If desired, the MM radar tracking filter may also include a summer for generating a signal output responsive to the weighted outputs of the first and second multipliers.

Abstract: A time domain communications system wherein a broadband of time-spaced signals, essentially monocycle-like signals, are derived from applying stepped-in-amplitude signals to a broadband antenna, in this case, a reverse bicone antenna. When received, the thus transmitted signals are multiplied by a D.C. replica of each transmitted signal, and thereafter, they are, successively, short time and long time integrated to achieve detection.

Abstract: In a radar apparatus, when the width of a target cannot be determined, the width is estimated in such a manner as not to erroneously identify the lane in which the target is traveling. Denoting the actual width of the target by D, the distance to the target by R, and the scanning step width of projection angle by A, the estimated value W for the width of the target is computed in accordance with the equation W=D?2R tan A.

Abstract: Sensors determine the kinematic measurements of a boosting missile, and the information is applied to a plurality of pairs or sets of filters, one of which is matched to the characteristics of a particular target type, and the other of which is general, and not matched to a particular target, for producing from each filter of the set missile position, velocity, acceleration, and specific mass flow rate states, and covariances of those states. From the filtered information, the estimates are made of at least missile mass flow rate, thrust, velocity at stage burnout, and remaining burn time. The likelihood is computed that the states and covariances from the filter sets represent the same target. The largest likelihood is selected as representing the target. In one mode, the estimated parameters are weighted and summed for a composite likelihood.

Abstract: A method, apparatus, and computer program product for joint kinematic and feature tracking are presented. Kinematic measurements and feature/class measurements regarding an object are received from a sensor. A probabilistic argumentation operation is performed on the feature/class measurements using information from a knowledge base and a track file ect to generate feature track likelihood scores regarding likely tracks for the object. Kinematic track likelihood scores are generated based on the kinematic measurements and the track file. Joint track likelihood scores are generated based on the feature track likelihood scores and the kinematic track likelihood scores. Joint track likelihood scores are used to generate a multi-frame track measurement association to determine a most likely track for the object. The track file is continually updated with the most likely track for the object, so that the most likely trajectory of the object is obtained.

Abstract: The synthesizer and method provide a relatively wideband swept frequency signal and include generating a first swept frequency signal with a first generator, and successively switching between different frequency signals with a second generator. Such switching creates undesired phase discontinuities in the output swept frequency signal. The first swept frequency signal is combined with the successively switched different frequency signals to produce the relatively wideband swept frequency signal, and the second generator is calibrated to reduce the undesired phase discontinuities during switching based upon the output swept frequency signal.

Abstract: Apparatus and method for multi-band, multi-frequency signal detection and transmission, comprising a multi-band wideband antenna, a receiver based on a plurality of synthesized down-converters and a plurality of synthesized programmable multi-channel phase-locked LOs, a DDS and a synthesized complex I/Q phase-detector, a control center based on a DSP connected with an ADC, plurality of DACs and an FPGA, and a plurality of synthesized programmable multi-channel transmitters synchronized with the DDS.

Abstract: The invention provides a radar that transmits a radio wave and receives an echo of the radio wave, which is characterized by possessing (1) a reception means that detects a beat signal of the echo and the radio wave, (2) a first frequency analysis means that analyzes the beat signal into frequency components, and detects a peak signal of frequency spectra obtained thereby, and (3) a second frequency analysis means that analyzes the beat signal into frequency components with a frequency resolution different from that of the first frequency analysis means, and detects a peak signal of frequency spectra obtained thereby.

Abstract: The invention is a system and method for verifying the radar signature of a pair of aircraft. The system includes a radar transmitter and receivers located in the leading and trailing edge of the wing at the wing tip of the aircraft such that when flying the aircraft in formation with one aircraft behind the other aircraft, each aircraft can illuminate the other and verify the radar signature of the other.

Abstract: A security system senses intrusions into a shipping container through the opening of doors, cutting an opening, or removing the doors from their hinges. Intrusion information is transmitted to a remote receiver without interrogation, thereby reducing power consumption. Sensing is accomplished by employing a range-gated micro-impulse radar (“RGR”) that generates microwave pulses that bounce around the interior of the container. The RGR includes a range gate that enables measuring reflected signals during the time gate period that is set for the time it takes a pulse to propagate a maximum distance within the container and reflect back. A direct current signal level is produced that represents the average reflected signal level within the container, and a Doppler shift measurement is made that represents motion inside the container. The signals are conveyed to the transmitter for conveyance to the remote receiver.

Abstract: Calibrating an antenna includes receiving a signal sent from a reference located within a region. The signal has a polarization within an expected polarization range. Polarization value sets are established in accordance with the expected polarization range. Polarization ratios are generated from the plurality of polarization value sets. A minimum polarization ratio variance for the plurality of polarization ratios is established. A polarization value set corresponding to the minimum polarization ratio variance is identified. A calibration correction is determined in accordance with the identified polarization value set.

Abstract: An apparatus for and method of employing synthetic aperture radar (SAR) images to automatically classify a target comprising emitting and collecting SAR signals at a plurality of squint angles, forming a plurality of SAR images of the target from the collected signals, the plurality of SAR images substantially having tilt angle diversity, automatically classifying the target from each of the plurality of SAR images, and generating a most probable target classification from the classifications of the plurality of SAR images.

Abstract: This invention relates to state estimation after processing measurements with time delays from multiple sensors of systems characterized by state variables and by multidimensional parameters, for which the latter are unknown and may vary arbitrarily in time within known physical bounds. If a measurement is time-late, apply the measurement to an out-of-sequence filter that uses a mean square optimization criterion that accounts for measurement errors and said bounding values, as well as the delay time, to optimally produce estimates of the true states of the system. If the measurement is not time-late, apply the measurements to an in-sequence filter that uses a mean square optimization criterion that accounts for measurement errors and said bounding values, to produce estimates of the true states of the system. The estimates are applied to one of (a) making a decision relating to the system, (b) operating a control system, and (c) controlling a process.

Abstract: SAR images are improved by a method for acquiring a synthetic aperture image from a sequence of periodic pulse returns where the sequence of periodic pulse returns is interspersed with interrupts, i.e. missing pulses. The interrupts mark the start and end of one or more segments, where the segments contain the periodic pulse returns form the SAR image. The method comprises the steps of: converting said pulse returns into a digital stream; performing an azimuth deskew on said digital stream to obtain a deskewed digital stream; forming a forward-backward data matrix from the deskewed digital stream for one or more segments; forming an average segment covariance from the forward-backward data matrix; computing a model order for the average segment covariance; computing one or more linear prediction coefficients using data contained in the forward backward data matrix, and model order; using the linear prediction coefficients to compute missing pulse returns belonging within the interrupts.

Abstract: Target detection in the presence of non stationary clutter is improved by a radar receiver on a moving platform for detecting a target using a plurality of short coherent arrays and a plurality of long coherent arrays synthesized from the short coherent arrays overlapping the target. The target is obscured by slow scale clutter and fast scale clutter in the vicinity of the target.

Abstract: A millimeter wave pulsed radar system includes a radar synthesizer having a voltage controlled oscillator/phase locked loop (VCO/PLL) circuit, direct digital synthesizer (DDS) circuit and quadrature modulator circuit that are operative to generate an intermediate frequency local oscillator signal (IF/LO signal). A radar transceiver is operative with the radar synthesizer for receiving the IF/LO signal. A transmitter section has a frequency multiplier that multiplies the IF/LO signal up to a millimeter wave (MMW) radar signal and a receiver section and includes a direct conversion mixer that receives a MMW radar signal and the IF/LO signal to produce I/Q baseband signals that are later digitized and processed.

Abstract: A method, an arrangement and a radar level gauging system for preventing interference, which radar level gauging system comprises at least two radar level gauges arranged to measure a filling level of a product kept in a container. Microwave pulses are transmitted towards the surface of said product and microwave pulses reflected by said surface are received by said at least two radar level gauges. Information is provided with said microwave pulses and said information is used for controlling the measurement pulses of said at least two radar level gauges.

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 object detecting device is provided whereby the number and size of detected objects can be determined without making the construction of the device more complex and the cost of components higher. The object detecting device includes multiple transmitter-receivers for transmitting radio waves and receiving reflected waves, each of the transmitter-receivers receiving both a reflected wave of a radio wave transmitted by itself and reflected waves of radio waves transmitted by other transmitter-receivers, a path-by-path reception distance computing unit for computing the path-by-path reception distance of every reflected wave and an object determination element for determining the number and/or size of detected objects based on the relationship between the reception distances computed by the path-by-path reception distance computing unit.

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. However, it is possible that the scan strategy is not realizable because of capacity constraints within the receiver system itself. One embodiment of the invention provides a method for detecting and correcting such a situation.

Abstract: Methods and apparatus are provided for radar systems using multiple pulses that are shorter than the expected range delay extent of the target to be imaged. In one implementation, a method for performing radar includes the steps of: transmitting a plurality of pulses, each pulse having a different center frequency and a time duration shorter than an expected range delay extent of a target, wherein a total bandwidth is defined by a bandwidth occupied by the plurality of pulses; receiving reflections of the plurality of pulses; and performing pulse compression on the received pulse reflections to generate a detection signal having a radar resolution approximately equivalent to the transmission and reception of a single pulse having the total bandwidth. In preferred form, the pulses comprise ultrawideband (UWB) pulses each occupying a sub-band of the overall system bandwidth.

Abstract: Motion compensation for coherent combination of pulses facilitates a SAR image of a scene on earth's surface. A great circle (406) is centered with respect to the earth's center, The great circle (406) has an axis (412) perpendicular to a first plane. Axis (412) passes through the earth's center. The first plane contains great circle (406) and includes the earth's center. Great circle (406) has a first center defined by an intersection of the first plane and axis (412). The scene has one or more radar scatterers and is located on a surface (402). The radar system is mounted on a moving platform (400) moving with a component of motion in a direction along great circle (406). The radar comprises a radar receiver for digitizing the radar returns having a phase from scatterers on surface (402), and a computer for focusing the phase of said radar returns from the scatterers on surface (402).

Abstract: A passive airborne mounted collision warning system suitable for light aircraft that enables an observer aircraft to determine the position of a nearby transponder-equipped target aircraft. The transponder-equipped target aircraft transmits replies responsive to interrogation signals from rotating secondary surveillance radars (SSR). In an embodiment of the invention, position of the target aircraft is determined based on the known position of the observer aircraft obtained e.g. via satellite navigation means such as GPS, the position of the SSR, and the bearing of the target aircraft measured by a direction finding antenna. The direction-finding antenna elements and the GPS receiver components are included in a device that is externally mounted on the observer aircraft. The data from the device is connected to a portable computer for processing and presentation to the pilot to alert him of the position of the target aircraft for avoiding collisions.

Abstract: A method of deinterleaving parameter descriptor word (PDW) data includes parallel scoring of pulses in an a posteriori search for associating of pulses based on proximity within a multi-parameter problem space. The a posteriori search includes scoring an oldest pulse against all newer pulses, and then scoring a next oldest pulse against all newer pulses. The associating utilizes at least one of a plurality of parallel computation modes, parallel tasks to operate on separate data fields, and multi-threading or multitasking that can implement one of parallel and configuration-overlaid operation, synchronized by events.

Abstract: A geographical region having an object to be tracked is divided into subregions, where adjacent disposed subregions partial overlap one another and the overlapping portions of adjacently disposed subregions share common states. A transition matrix is used to represent the terrain in a subregion and each subregion can have N geographical states and four (4) additional transition states. A regional tracker is used to estimate state sequences for each new observation of the object. Tracking continues until the process is complete or until the probability that the vehicle is in another new subregion occurs. Tracking performed between adjacently disposed subregions is based, at least in part by, the direction represented by the transition state. Tracking into a new subregion from an adjacently disposed old subregion begins precisely where tracking for the old subregion ended using the states that are common in the overlapping portions of the adjacently disposed subregions.

Abstract: A bi-static continuous wave radar system and related methods for detecting incoming threats from ballistic projectiles includes a remote source of RF illumination, and a local receiver installed in one or more target aircraft. A first receiving channel acquires direct path illumination from the source and provides a reference signal, and a second receiving channel acquires a scatter signal reflected by a projectile. A processor coupled to each receiver corrects scatter signal Doppler offset induced by relative source motion, isolates narrowband Doppler signals to derive signatures characteristic of the projectile, and by executing appropriate algorithms, compares the derived signatures to modeled signatures stored in memory. If the comparison yields a substantial similarity, the processor outputs a warning signal sufficient to initiate defensive countermeasures.

Abstract: A system and method for performing in-orbit alignment calibration using on-board attitude sensors to improve reflector alignment after deployment to improve spacecraft pointing.

Abstract: A radar detection process includes computing a derivative of an FFT output signal to detect an object within a specified detection zone. In one embodiment, a zero crossing in the second derivative of the FFT output signal indicates the presence of an object. The range of the object is determined as a function of the frequency at which the zero crossing occurs. Also described is a detection table containing indicators of the presence or absence of an object within a respective radar beam and processing cycle. At least two such indicators are combined in order to detect the presence of an object within the detection zone and with changing range gates in each of the antenna beams the coverage of the detection zone can be varied.

Abstract: A mechanism for combining signals of multiple radars to achieve increased range, radar sensitivity and angle accuracy is provided. A first signal beam is radiated from an antenna of a first radar in the direction of a target. A second signal beam is radiated from an antenna of a second radar in the direction of the same target. The echo signals from the first signal beam and the second signal beam are received at both radars. The echo signals received at the first radar are processed to produce first radar processed echo signals and the echoes signals received at the second radar are processed to produce second radar processed echo signals. The first and second radar processed echo signals are combined to form an aggregate value.

Abstract: An imaging system includes an optical (visible-light or near IR) imaging system and a microwave imaging system. The optical imaging system captures an optical image of the object, produces optical image data representing the optical image and extracts optical image information from the optical image data. The microwave imaging system produces microwave image data representing a microwave image of the object in response to the optical image information.

Abstract: A see-through-the-wall (STTW) imaging system uses a plurality of geographically separated positioning transmitters to transmit non-interfering positioning signals. An imaging unit generates a synthetic aperture image of a target by compensating for complex movement of the imaging unit using the positioning signals. The imaging unit includes forward and aft positioning antennas to receive at least three of the positioning signals, an imaging antenna to receive radar return signals from the target, and a signal processor to compensate the return signals for position and orientation of the imaging antenna using the positioning signals. The signal processor may construct the synthetic aperture image of a target from the compensated return signals as the imaging unit is moved with respect to the target. The signal processor may determine the position and the orientation of the imaging unit by measuring a relative phase of the positioning signals.

Abstract: Provided is a radar apparatus capable of continuously and stably making a detection of a target even if a reflected wave from a target already detected falls into obscurity due to the presence of low-frequency noises or reflected waves from other targets. An estimated value of information on a target to be obtained when the target is detected in the present cycle are acquired from the target detected in a previous cycle. When a peak compatible with the estimated value is detected in only one of a frequency-rising section and a frequency falling section of a radar wave, if the frequency of the non-detected peak pertains a low-frequency noise domain or if a side-by-side travel flag is set with respect to the target detected in the previous cycle, the non-detected peak is considered as buried by low-frequency noises or peaks of other targets, and a peak pair corresponding to the detected target is extrapolated.

Abstract: A correlating polarimeter is provided for correlating a received waveform of a wideband electromagnetic signal with a predetermined waveform. The correlating polarimeter may include a first antenna for receiving an electromagnetic signal and a modulator interconnected with the first antenna for modulating the electromagnetic signal whereby a modulated electromagnetic signal results which contains a different polarization state for each frequency of the electromagnetic signal with the amplitude of each frequency component of the modulated electromagnetic signal being a function of the particular polarization state of each frequency component of the electromagnetic signal.

Abstract: An improved system and methods for correlating an interrogation-based air traffic surveillance intruder, such as an Traffic alert and Collision Avoidance System (TCAS) intruder, and a GPS-based air traffic surveillance target, such as an Automatic Dependent Surveillance Broadcast (ADS-B) target to minimize or eliminate the display of two symbols for the same intruder/target on the CDTI of an aircraft. The method comprises the steps of receiving ADS-B data at a processing unit and calculating select component deltas for the ADS-B data versus an entry in a TCAS intruder file. Progressive weights are assigned to the deltas and the progressive weights are summed, resulting in a total confidence score. Total confidence scores of ADS-B target and TCAS intruder pairs are compared to determine correlation between the ADS-B target and the TCAS intruders.

Abstract: Resolution of a radar operating within a bandwidth is improved by defining a quantity of substantially rectangular sub-band filters to subdivide the bandwidth in the frequency domain into the quantity of sequential sub-bands having a sub-bandwidth. Each signal sent by the radar is associated with a transmission temporal moment. Each of the quantity of return signals received is routed in one to one correspondence to the sub-band filters, each signal being received at a corresponding sub-band filter. The return signals received are summed by synchronizing the associated transmission temporal moment to produce a reconstructed return signal.

Abstract: The system and method for standoff detection of human carried explosives (HCE) is a portable system that automatically detects HCE up to a range of 200 meters and within seconds alerts an operator to HCE threats. The system has radar only, or both radar and video sensors, a multi-sensor processor, an operator console, handheld displays, and a wideband wireless communications link. The processor receives radar and video feeds and automatically tracks and detects all humans in the field of view. Track data continuously cues the narrow beam radar to a subject of interest, the radar repeatedly interrogating cued objects, producing a multi-polarity radar range profile for each interrogation event. Range profiles and associated features are automatically fused over time until sufficient evidence is accrued to support a threat/non-threat declaration hypothesis. Once a determination is made, the system alerts operators through a handheld display and mitigates the threat if desired.

Abstract: A stepped-frequency chirped waveform improves SAR groundmapping for the following reasons. Range resolution in SAR image is inversely proportional to the transmitted signal bandwidth in nominal SAR systems. Since there is a limit in the transmitted bandwidth that can be supported by the radar hardware, there is a limit in range resolution that can be achieved by processing SAR data in conventional manner. However, if the frequency band of the transmitted signal is skipped within a group of sub-pulses and received signal is properly combined, the composite signal has effectively increased bandwidth and hence improvement in range resolution can be achieved. The proposed new and practical approach can effectively extend the limit in range resolution beyond the level that is set by the radar hardware units when conventional method is used.

Abstract: A security inspection system uses microwave radiation to image targets on a human subject or other item. The system includes an array of antenna elements that are programmable with a respective phase delay to direct a beam of microwave illumination toward a target on the human subject or item. The antenna elements are further capable of receiving reflected microwave illumination reflected from the target. A processor is operable to measure an intensity of the reflected microwave illumination to determine a value of a pixel within an image of the human subject or item. Multiple beams can be directed towards the human subject or item to obtain corresponding pixel values for use by the processor in constructing the image.

Abstract: Estimating an antenna pointing error includes receiving a signal sent from a reference located within a region. A polarization ratio is evaluated over the region. A minimum polarization ratio variance for the polarization ratio is established. A location corresponding to the minimum polarization ratio variance is identified. An antenna pointing error is estimated from the identified location.

Abstract: A radar detector for alerting an operator of a motor vehicle to an incoming police radar signal. This radar detector includes a microprocessor; a circuit coupled to the microprocessor for detecting the incoming police radar signal; and a global positioning system receiver coupled to the microprocessor. Upon detection of an incoming radar signal, the radar detector can utilize the position, velocity, and/or heading data from the global positioning system receiver to determine whether to generate an alert.