Abstract: A radiometer system includes a housing and an RF board contained within the housing. Balanced radiometer channels receive an unknown signal and known reference. Each balanced radiometer channel includes at least one quadrature hybrid and amplifier circuit to provide distributed gain and an amplified output signal. A detection circuit receives and detects the amplified output signal forming a detected signal. A controller board is contained within the housing and has an integration circuit and microcontroller that receives the detected signal and performs video signal digitization and conditioning and real-time corrections on any radiometer channels to account for changes in temperature or gain.

Abstract: A radiometer system includes a housing and an RF board contained within the housing. Balanced radiometer channels receive an unknown signal and known reference. Each balanced radiometer channel includes at least one quadrature hybrid and amplifier circuit to provide distributed gain and an amplified output signal. A detection circuit receives and detects the amplified output signal forming a detected signal. A controller board is contained within the housing and has an integration circuit and microcontroller that receives the detected signal and performs video signal digitization and conditioning and real-time corrections on any radiometer channels to account for changes in temperature or gain.

Abstract: A radiometer includes a housing and an RF board carried by the housing. A hybrid and amplifier circuit receives an unknown signal and a known reference signal. A switch receives signals as inputs from the hybrid and amplifier circuit and switches between the inputs. A detection circuit receives and detects the signal from the switch forming a detected signal. A controller board is carried by the housing and an integration circuit and processor receive the detected signal and produces a digital output.

Abstract: A method of measuring a field-of-view (FOV) of an optical sensor includes the steps of: (a) uniformly illuminating a FOV of the optical sensor; (b) moving, at an angle of motion, a slit across the FOV and illuminating the optical sensor through the slit; (c) measuring an optical response of the sensor through the slit, at evenly spaced positions of the moving slit; (d) changing the angle of motion and repeating steps (b) and (c); (e) repeating step (d) for equally spaced angles of motion; and (f) constructing a two-dimensional map of the FOV of the optical sensor, after completing step (e). Constructing the two-dimensional map of the FOV includes filtering the measured data using a filtered backprojection algorithm, and interpolating among the filtered measured data to form the two-dimensional map.

Abstract: A radiometer includes a housing and an RF board carried by the housing. A hybrid and amplifier circuit receives an unknown signal and a known reference signal. A switch receives signals as inputs from the hybrid and amplifier circuit and switches between the inputs. A detection circuit receives and detects the signal from the switch forming a detected signal. A controller board is carried by the housing and an integration circuit and processor receive the detected signal and produces a digital output.

Abstract: A radiometer system includes a housing and an RF board contained within the housing. Balanced radiometer channels receive an unknown signal and known reference. Each balanced radiometer channel includes at least one quadrature hybrid and amplifier circuit to provide distributed gain and an amplified output signal. A detection circuit receives and detects the amplified output signal forming a detected signal. A controller board is contained within the housing and has an integration circuit and microcontroller that receives the detected signal and performs video signal digitization and conditioning and real-time corrections on any radiometer channels to account for changes in temperature or gain.

Abstract: Radiometers detect radio wavelength electromagnetic radiation and typically have an antenna (16), an amplifier (18) and a detector (20). All three of these components have response characteristics that may be dependent on temperature, and in the case of systems using radiometer arrays dependent upon temperatures throughout the system. Different temperatures across a multi-channel antenna and differential channel temperature response can result in poor image quality from imaging radiometers. Resolution of a linear array of detector horns is limited by the size of the horns.

Abstract: Method and system for synthetic aperture radiometry not limited by the Van Cittert-Zernike theorem and the quasi-monochromatic assumption. A radiometer system (300) for imaging the emissions from a distribution of incoherent emission sources located within a target area comprising a first antenna (322) configured to receive a first signal (326) emitted primarily from a target area, and a second antenna (324) configured to receive a second signal (327) emitted primarily from the target area. The first and second antennas may be located at approximately the same distance from the target area (310) or at substantially different distances from the target area (310). The radiometer system (300) is configured to allow the second antenna (324) to move faster than the first antenna (322) with respect to the target area (310), with the second antenna (324) moving along a pre-determined trajectory corresponding to a synthetic aperture (430).

Abstract: Apparatus and a method for radiometric temperature measurement comprises a radiometer receiver coupled to an antenna/calibration switch that has coupled thereto a brightness temperature signal. A driver coupled to the antenna/calibration switch controls the operation of the switch between an antenna mode and a calibration mode. An adjustable cold/warm noise source is coupled to the antenna/calibration switch to provide a calibration radiation temperature applied through the antenna/calibration switch in the calibration mode to the radiometer receiver. An output of the radiometer receiver is coupled to the adjustable cold/warm noise source and is adjusted in accordance with the output of the radiometer receiver for a null comparison measurement. Also coupled between the output of the radiometer receiver and the antenna/calibration switch is a mode selector switch that operates to a mode one position to couple the output of the radiometer receiver to the adjustable cold/warm noise source.

Abstract: Radiometers detect radio wavelenth electromagnetic radiation and typically have an antenna (16), an amplifier (18) and a detector (20). All three of these components have response characteristics that ma be dependent on temperature, and in the case of systems using radiometer arrays dependent upon temperatures throughout the system. Different temperatures across a multi-channel antenna and differential channel temperature response can result in poor image quality from imaging radiometers. Resolution of a linear array of detector horns is limited by the size of the horns.

Abstract: Method and system for synthetic aperture radiometry not limited by the Van Cittert-Zernike theorem and the quasi-monochromatic assumption. A radiometer system (300) for imaging the emissions from a distribution of incoherent emission sources located within a target area comprising a first antenna (322) configured to receive a first signal (326) emitted primarily from a target area, and a second antenna (324) configured to receive a second signal (327) emitted primarily from the target area. The first and second antennas may be located at approximately the same distance from the target area (310) or at substantially different distances from the target area (310). The radiometer system (300) is configured to allow the second antenna (324) to move faster than the first antenna (322) with respect to the target area (310), with the second antenna (324) moving along a pre-determined trajectory corresponding to a synthetic aperture (430).

Abstract: An antenna array of “n” individual parabolic dishes is arranged about a center in subarrays extending in North, East, South and West rows. Signals received by the antennas are combined into representations of the electromagnetic environment as viewed with various simultaneous beam geometries, through a combination of analog signal summation, and digital implementation of aperture synthesis techniques. All antennas monitor the same portion of sky. The array is able to scan the sky without physically moving the antennas. The angular resolution of the array greatly exceeds that of the individual antennas. A variety of different research objectives, such as targeted searches, all-sky surveys, sky mapping, interference studies, the study of a variety of natural astrophysical phenomena, and the search for intelligently generated microwave emissions of possible extraterrestrial origin, may be realized simultaneously.

Abstract: An imaging system (10) that includes a passive millimeter-wave camera (14)employing a focal plane array (60) of millimeter-wave integrated circuitry receivers (32). The camera (14) images a scene (58) that may include one or more beacons (12). The beacons (12) transmit millimeter-wave radiation signals (16) that are modulated by a modulator (24) so that the beacons (12) can be distinguished, and possibly provide communications in addition to beacon location. The receivers (32) in the camera (14) employ a demodulator (40) to demodulate the detected millimeter-wave signals from the scene (58). Therefore, not only does the camera (14) image the beacons (12) in the scene (58), but also can separate and decipher communications signals from the beacons (12).

Abstract: An aperture synthesis radiometer operating in fully polarimetric mode. The measuring receivers are connected selectively to the polarization ports of the array elements following selected switching sequences thereby to provide the required cross-correlations that allow fully polarimetric operation. The polarization switching scheme used enable measurements to be performed with a minimum degradation in sensitivity using single channel receivers.

Abstract: A convection induced turbulence (CIT) detection system performs a nowcast algorithm to detect CIT along the flight path of an aircraft using power returns from an airborne whether radar. Additional meteorological data is optionally provided by onboard sensors and/or data link from ground sources. A nowcast predicting turbulence along the flight path in the near future alerts the pilot to the likelihood of encountering clear air turbulence.

Abstract: A radiometer calibrating system utilizes an adjustable noise source for calibrating a radiometer. The noise source includes a transistor configured as a noise equivalent circuit having a gate port, drain port and source port. A source inductance providing series feedback for the noise source has one end coupled to the source port of the noise equivalent circuit and another end connected to the ground. A bias circuit controls the amount of DC bias applied to the noise equivalent circuit. In order to match the impedances in the noise source, an output impedance matching network is connected to the drain port and an input impedance matching network is connected to the gate port of the noise equivalent circuit. The output and input impedance networks have an output port and input port, respectively.

Abstract: An aperture synthesis radiometer operating in fully polarimetric mode. The measuring receivers are connected selectively to the polarization ports of the array elements following selected switching sequences thereby to provide the required cross-correlations that allow fully polarimetric operation. The polarization switching scheme used enable measurements to be performed with a minimum degradation in sensitivity using single channel receivers.

Abstract: The passive polarimetric microwave radiometer is a simple and low cost radiometric icing detection system that operates over a suitable set of frequency bands in the millimeter wave region of the spectrum to provide useful signatures for detecting aircraft icing conditions. This basic passive polarimetric microwave radiometer observes along a single line of sight and consists of a dual polarization dual frequency radiometer that is pointed in the direction of interest, such as the projected flight path, and operates at a frequency which is sensitive to the polarizing effects of hydrometeors. The passive polarimetric microwave radiometer could also observe in a horizontal plane around the aircraft or ground station and include both vertical and horizontal scanning capability.

Abstract: A passive ranging system measured spectra of solar radiation off an adjacent spot and a distal target. Reflected solar radiation and differential attenuation are used to estimate target range. A comparison of absorption spectra from the solar illuminated distal target compared to the adjacent location is performed. Since the sun's position is always known, the increased absorption due to a distant target is derived from the differential between the adjacent spot and the distal target.

Abstract: Apparatus and method for forecasting the quality of radio communication links on a short-term basis are disclosed, the apparatus including at least one, and preferably an ensemble of, sensors providing output indicia indicative of evolving atmospheric and/or ionospheric conditions in the vicinity of a monitored communication link. The sensors may include any device that provides data containing predictive information, such as a microwave radiometer for receiving atmospheric emissions that are related to atmospheric scattering and absorption of radio propagation, input for measurement of the signal-to-noise ratio of the radio link carrier, and sensors of surface meteorology including barometric pressure, temperature, and surface winds direction and velocity. Data provided is processed utilizing mathematical inversion (also referred to as function estimation) techniques to provide predictions of changing link quality in the short-term (e.g.

Abstract: A radiometry system including an aperture synthesis antenna array type, including plural antenna elements, distributed in an antenna plane relative to at least one axis, according to a determined law. Each antenna element includes first and second coupling probes sensitive to hyper-frequency electromagnetic signals with dual linear polarization in quadrature (arbitrarily referred to as horizontal and vertical polarizations). The probes are connected two by two with electric receiving circuits to create a synthetic aperture. The horizontal (fH1-fH4) and vertical (fV1-fV4) coupling probes of successive antenna elements (eA1-eA4) are oriented in the antenna plane (At′), along each of the axes (&Dgr;), such that at least one of the horizontal or vertical probes (fH1-fH4, fV1-f4) presents a 180° phase shift from one antenna element to the other (eA1-eA4), with the phase shift obtained by a sequential 90° rotation of those probes (fH1-fH4, fV1-fV4).

Abstract: The object of this Patent is an automatic ship position and course logger of the type comprised of a positioning system (1), a communications system (2), a data processing system (3), a graphic display video monitor (4), a graphics printer (5) and a user keyboard (6).

Abstract: A passive ranging optical system is coupled to an active radar system. The passive ranging optical system provides range and rate information to the active radar system. After receiving the range and rate information, the active radar system uses fewer transmission pulses but achieves higher resolution of the range of the target because of improved range gate information.

Abstract: A spinning strip aperture imaging radiometer sensor system and data processing methods for detecting moving objects derived from a plurality of image frames acquired by a strip aperture imaging sensor. A moving object in any individual image frame results in a motion smear signature in the total synthesized image. The motion smear signature is processed to detect the moving objects. One embodiment of the system comprises a rotating strip aperture telescope, a two dimensional detector array that detects images in the telescope's focal plane, a rotation compensation device that prevents rotational smear during integration time of detectors of the array, a signal processor that records a plurality of image frames of a scene imaged by the telescope as it rotates around its optical axis, and that implements method(s) for detecting the moving objects present in the recorded images.

Abstract: A clear air turbulence (CAT) detection system performs a nested grid modeling algorithm to detect CAT along the flight path of an aircraft. The aircraft stores coarse simulation information and utilizes the information to perform large scale weather modeling over a large grid. On board sensors are utilized to generate observational information to model atmospheric conditions within a smaller grid, nested within the larger grid, and including the flight path of the aircraft. A nowcast predicting turbulence along the flight path in the near future alerts the pilot to the likelihood of encountering clear air turbulence. A data link may be utilized to receive coarse simulation data or observational data from sources external to the aircraft. Additionally, the coarse simulation information may include turbulence forecast data and the observational information is used to refine the turbulence forecast to more accurately predict clear air turbulence along the flight path of the aircraft.

Abstract: A spinning strip aperture imaging radiometer sensor system and data processing method for synthesizing a super-resolved scene estimate (super-resolved scene) from a plurality of image frames acquired by the strip aperture imaging sensor system. One embodiment of the imaging system comprises a rotating strip aperture wide field of view telescope, a two dimensional detector array for detecting images in the focal plane of the telescope, rotation compensation apparatus for preventing rotational smear during the integration time of the detectors, a signal processor for recording a plurality of image frames of a scene that is imaged by the telescope as it rotates around its optical axis, and an estimation processor employing the present method for synthesizing the super-resolved scene estimate from the recorded images.

Abstract: A microwave active noise source and method used for calibrating a radiometer includes a transistor configured as a noise equivalent model having a gate port, drain port and source port. During calibration of the radiometer the drain port is terminated and a bias circuit applies DC bias to the noise equivalent model. The bias circuit controls the DC bias such that a hot thermal radiation temperature and a cold thermal radiation temperature are alternately generated at the gate port of the noise equivalent model. A source inductance coupled to the source port of the noise equivalent model provides series feedback. To match the impedances in the noise source, an output matching impedance network is connected to the drain port and an input matching impedance network is connected to the gate port of the noise equivalent model. The input matching impedance network includes an input port for outputting the hot and cold thermal radiation temperatures used to calibrate the radiometer.

Abstract: A technique is provided for passively detecting the presence and location of an underground object. A plurality of individual antennas positioned in a linear array are directed to receive fields of view which are mutually parallel in azimuth. The linear array is then focused at a plurality of different angles in azimuth for passively acquiring low level random noise signals in the RF spectrum which are emitted by the underground object and by the intervening media.

Abstract: The invention concerns an interferometric hyperfrequency radiometry system comprising an antenna being subject to a rotation movement around the vertical direction, with a boresight axis forming an angle with a nadir direction so as to obtain a conical scanning. The antenna is a planar array antenna, of an interferometric type with distributed elements, such that the instantaneous field of vision consists of pixels, along at least one axis perpendicular to the conical scanning for an unidimensional interferometric antenna, and along two axes for a bidimensional interferometric antenna. The elements of the interferometric antenna furthermore are connected into sub-arrays.

Abstract: This invention relates to a process for measuring an antenna diagram in which:the antenna (30) is connected to a receiver (33) capable of supplying C/No measures (the ratio of the useful signal power to the noise power spectral density) and possibly phase variation measurements;the antenna (30) is placed at the end of a mast (32) or a carrier satellite facing towards the sky to track the satellites in a constellation, the antenna reception band being included in the satellite antenna transmission band;the C/No ratio and phase variations are automatically recorded for a given period;the diagram for the said antenna is deduced by calculation.

Abstract: A radiometer and a method for indicating water content and water content change caused by water and/or liquid water are disclosed. According to the method, changes of noise temperature values are observed by receiving microwave electromagnetic radiation at a medium frequency. This medium frequency is considerably below the lowest absorption resonance (approximately 22 GHz) of water molecules. At least one noise temperature value is set as reference value, and noise temperature changes are compared with the reference level.

Abstract: A photographic camera (10) that generates still photographs or images of a scene by detecting millimeter-wave radiation (16). The camera (10) includes an imaging lens (14) that collects the millimeter-wave radiation (16) and focuses the radiation on a plurality of receiver modules (32) positioned in the focal point of the lens (14) where each receiver module (32) includes a plurality of direct detection millimeter-wave receivers (36). In one embodiment, the plurality of receiver modules (32) are mounted on a single sensor card (28), where the receiver modules (32) on the card (28) are aligned in one direction. Each receiver (36) includes detector circuitry that detects the radiation of a pixel in the scene. Electrical signals from the receiver modules (32) are sent to a processing unit (38) on the sensor card (28). In one embodiment, the radiation (16) collected by the lens (14) is directed to a scanning mirror (18) that scans across the scene at a predetermined rate to generate the entire image.

Abstract: An electromagnetic pickup device (64) for receiving electromagnetic signals (62) is disclosed that comprises an H-field probe (68) having an end (78) the is insertable into the earth (16) for receiving the H-field component of the electromagnetic signal (62) and a plurality of E-field probes (66) that are radially disposed about the H-field probe (68) and electrically isolated from the H-field probe (68), each having an end (76) that is insertable into the earth (16) for receiving the E-field component of the electromagnetic signal (62).

Abstract: A rotating mirror drum radiometer imaging apparatus. The apparatus generally comprises a two-sided mirror, a drum for securely supporting the two-sided mirror therein at an angle of preferably about 45 degrees relative to a longitudinal axis of symmetry extending through the drum, support walls for supporting the drum for rotational movement, and a motor and drive wheel for rotationally driving the drum. In one embodiment the drum includes first and second cut-outs in a side surface thereof. The cut-outs are further spaced preferably about 180 degrees from each other about the longitudinal axis of symmetry and enable a transmitted signal to be alternately received therethrough by first and second sides of the two-sided mirror as the drum and mirror are concurrently rotated by the motor and drive wheel. A first antenna is disposed adjacent a first end of the drum and a second antenna is disposed adjacent a second end of the drum.

Abstract: A radiometric data acquisition and display system is provided. The system has a detector assembly with a boom. A radiometer is connected at an end of the boom. The radiometer has a sensor head including an antenna horn to acquire radiometric data from an area of interest. A rangefinder is constructed and arranged to provide location data indicative of a position of the sensor head, and a data processor is connected to receive the location data from the rangefinder and the radiometric data from the radiometer. The data processor includes signal processing circuitry and a display connected to the computer. A method of acquiring and displaying a radiometric image of an object is also provided.

Abstract: A rotating mirror drum radiometer imaging apparatus. The apparatus generally comprises a two-sided mirror, a drum for securely supporting the two-sided mirror therein at an angle of preferably about 45 degrees relative to a longitudinal axis of symmetry extending through the drum, support walls for supporting the drum for rotational movement, and a motor and drive wheel for rotationally driving the drum. In one embodiment the drum includes first and second cut-outs in a side surface thereof. The cut-outs are further spaced preferably about 180 degrees from each other about the longitudinal axis of symmetry and enable a transmitted signal to be alternately received therethrough by first and second sides of the two-sided mirror as the drum and mirror are concurrently rotated by the motor and drive wheel. A first antenna is disposed adjacent a first end of the drum and a second antenna is disposed adjacent a second end of the drum.

Abstract: A direct detection receiver for a passive microwave and millimeter wave radiometric imaging system. The receiver includes a balanced switch low-noise amplifier (BSLNA). A front-end, low-noise amplifier (LNA) is inserted before the BSLNA to achieve a low-noise figure, as well as provide sufficient gain to minimize the input noise figure degradation due to loss of the BSLNA. A high-electron mobility transistor (HEMT) diode is used as a power detector. The front-end amplifier, BSLNA and diode are process compatible for monolithic integration.

Abstract: An apparatus for measuring the properties of the tropopause includes a variable frequency microwave radiometer operating over a range of from about 118.0 to about 119.0 GHz. The radiometer receives as an input a frequency selector signal and produces as an output a measured power level at a measurement frequency corresponding to the input frequency selector signal. The apparatus further includes a feedback controller having as an input the measured power level and producing as an output the frequency selector signal. The feedback controller varies the frequency selector signal to a target frequency so as to produce a minimum value in the measured power level. The tropopause equivalent altitude is determined from the target frequency.

Abstract: An electrically scanning microwave radiometer (ESMR) is mounted in a flying body orbiting a planet and operative to measure the surface of the planet. A receiving antenna having its cylindrical or multiplicated radiation face is used to scan the surface of the planet along a conical section. A receiver detects the radiation from the planet which is received by the receiving antenna. The detected signals are then integrated by an integrator. The integrated value is converted into a digital value by a signal processor. The digital value is transmitted to an earth station as a measurement signal after it has been formatted. The receiving antenna may be either of a cylindrical phased-array antenna or multiplicated phased-array antenna. The cylindrical and multiplicated faces may be replaced by inverse-directional cylindrical and multiplicated faces, respectively. Further, the receiving antenna may be of a composite or multi-beam type which includes any combination of the aforementioned surfaces.

Abstract: A system and method of passive ranging for a luminous target employs a prior knowledge and a present measurement of its electromagnetic spectrum during a target acquisition procedure and, subsequently, during analysis of the spectrum to determine the effects of atmospheric attenuation on various parts of the spectrum. Relative attenuation of various spectral components by the atmosphere is indicative of target range.

Abstract: A rotating mirror drum radiometer imaging apparatus. The apparatus generally comprises a two-sided mirror, a drum for securely supporting the two-sided mirror therein at an angle of preferably about 45 degrees relative to a longitudinal axis of symmetry extending through the drum, support walls for supporting the drum for rotational movement, and a motor and drive wheel for rotationally driving the drum. In the preferred embodiment the drum includes first and second cut-outs in a side surface thereof. The cut-outs are further spaced preferably about 180 degrees from each other about the longitudinal axis of symmetry and enable a transmitted signal to be alternately received therethrough by first and second sides of the two-sided mirror as the drum and mirror are concurrently rotated by the motor and drive wheel. A first antenna is disposed adjacent a first end of the drum and a second antenna is disposed adjacent a second end of the drum.

Abstract: A detection system will detect and identify self-propelled objects, such as missiles, which create a hot exhaust plume. The exhaust plume has radiation which flickers with a frequency range of interest. This frequency range can be detected with various detectors, such as an ultraviolet detector or radio frequency detector. A warning signal will indicate if frequencies are encountered within the frequency range of interest. The detecting system will also detect light and radio frequency radiation from pressure waves created by supersonic components of the flying object. This radiation has low frequency components which can be filtered and identified.

Abstract: A method of identifying antenna-mode scattering centers in an aperture device or array from planar near field measurements. Antenna-mode scattering centers may be determined for aperture assemblies, phenomenological models of apertures, and antenna arrays comprising a feed and an array of antenna elements. The method uses a scanning probe and receiver for making near field measurements. A feed horn and signal source illuminates the device. An absorber is disposed between the device and the probe and this combination is illuminated. A first set of data is collected over a planar surface in a near field region of the device. The device is then illuminated with the absorber removed. A second set of data is collected over a planar surface in a near field region of the device. The difference between the first and second sets of data is determined to provide data indicative of the near field response of the probe to the near field scattered from the device.

Abstract: A camera system in which microwave radiation from objects in a field-of-view is collected by an antenna having beam directions which are a function of the beam frequency. The collected radiation is used to modulate an optical beam to impose upon the beam spectral components which are functions of the frequencies of the microwave radiation. The modulated beam is then analyzed by an optical spectrum analyzer to produce an image of objects in the field of view. In a simple embodiment of the invention a one dimensional image is produced. This one dimensional image can be converted to a two dimensional image by panning the camera system or mounting the camera on a moving platform. In this preferred embodiment the spectrum analyzer comprises an angle-frequency filter (preferably an etalon). The portion of the modulated beam passing through the etalon is directed in a number of directions, the directions being a function of the spectral components of the modulated beam.

Abstract: In an IRST system, a determination of the range and type of a detected target may be made as follows. Atmospheric transmittance and background spectral radiance is estimated from available meteorological data and then, at each of consecutive scans, the contrast irradiance in the direction of a target is measured as well as the azimuth and elevation of said target. A target type is selected from a library of target types storing signatures of the target types considering the measured contrast irradiance as well as the measure of the contrast irradiance at the previous scan (if any). The range of the target is calculated considering the selected target type, the estimated atmospheric parameters and the measured contrast irradiance. Where the target has other than a radially inbound trajectory the trajectory of the target is estimated and the target type selected from the library, considering the estimated trajectory.

Abstract: The thermodynamics-based signal receiver transforms contiguous segments of a received signal into thermodynamics-related quantities using an analog of a statistical-mechanics-related quantities using an analog of a statistical-mechanics expression for a thermodynamic variable and uses these thermodynamics-related quantities as the means to measure changes in the signal as a function of time or origin. The changes that are of interest are those associated with either signal level or signal structure. Signal-processing analogs of statistical mechanics expressions for thermodynamic variables are measures that respond in some fashion to either type of change. By comparing thermodynamics-related transformations of received signals, one can obtain information about the emitters of the received signals and the nature of the medium through which the signals were propagated.

Abstract: A spinning strip aperture imaging radiometer sensor system and data processing method that is capable of synthesizing full circular aperture images from a plurality of image frames acquired by the strip aperture imaging sensor. One embodiment of the imaging system comprises a rotating strip aperture wide field of view telescope, a two dimensional detector array used to detect images in the telescope's focal plane, a rotation compensation device used to prevent rotational smear during the integration time of the detectors, a signal processor used to record a plurality of image frames of a target scene that is imaged by the telescope as it rotates around its optical axis, and a signal processor and method used to synthesize the full circular aperture image from the recorded images. The operation of the full aperture image synthesis method hinges upon the ability of the rotating strip aperture to measure all of the spatial frequencies contained in a full circular aperture image measurement.

Abstract: A dual linearly-polarized cross-correlating radiometer including an apparatus for calibrating the cross-correlating channel of the radiometer is described. The apparatus for calibrating the cross-correlating channel comprises a first calibration load, a second calibration load positioned perpendicularly thereto, and means for rotating the calibration loads relative to the feedhorn of the radiometer. The calibration loads are moved through several angular positions and the output voltages of the cross-correlating channel are measured at the various angular positions and used to estimate the gains and offset of the cross-correlating channel.

Abstract: A contraband detection system especially suited for detecting concealed non-metallic contraband such as ceramic or plastic weapons or illegal drugs carried by a person is disclosed. Plural sources of quasi-coherent millimeter wave radiation are disposed so as to uniformly illuminate a field of view. In the preferred embodiment, the radiation emitted by the sources is linearly polarized in a single plane such that the polarization of the radiation with respect to the plane in which linearly polarized radiation is preferentially received by the detectors can be controlled. For detection of dielectric objects, such as ceramic weapons or narcotics, these planes of polarization should be orthogonal to one another. The detector is a staring array which does not require scanning to generate an image of the entire field of view; the signal provided by each element of the detector array corresponds to the illumination reflected from objects in a single portion of the field of view.

Abstract: An end-to-end microwave receiver system contained in a single miniature hybrid package mounted on a single heatsink, including an input end connected to a microwave receiver antenna and an output end which produces a digital count proportional to the amplitude of a signal of a selected microwave frequency band received at the antenna and corresponding to one of the water vapor absorption lines near frequencies of 20 GHz or 30 GHz. The hybrid package is on the order of several centimeters in length and a few centimeters in height and width. The package includes an L-shaped carrier having a base surface and a vertical wall extending up from the base surface and forming a corner therewith, external connection pins extending through the vertical wall. Modular blocks rest on the base surface against the vertical wall and support microwave monolithic integrated circuits on top surfaces thereof connected to the external connection pins.