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. Real-time imaging of concealed dielectric and metallic objects is thus made possible.

Contraband detection system

A position location system includes multiple base stations spaced over a region. A portable unit within the region transmits a locating signal which is received by the base stations. The base stations report amplitude, phase and time data related to the locating signal to a control station. The control station includes a processor and memory that combine the data from all of the participating base stations to directly compute an optimal estimate of the location of the portable unit. The control station generates an ambiguity function based upon the probability that the portable unit is located at a particular position. By optimizing the ambiguity function, the error in the computation is minimized to produce an accurate position estimate.

Position location system and method

Tapering the surface current density near the edges of a parabolic reflector antenna lowers the sidelobe level of the reflector. The current density is tapered by placing tapered resistive edge loads on the reflector for gradually decreasing the conductivity from the center of the reflector to the edge.

Low sidelobe resistive reflector antenna

A tapered slot antenna (20) includes a dielectric (22) with a metallization layer (24) deposited on one side. The metallization layer (24) is etched to the dielectric substrate (22) to form a tapered slot (26, 28, 30, 32). In order to tune the antenna 20), for example, such that the E and H field beam width are symmetrical, the (22) extends beyond the wide portion of the slot as a dielectric loading (26, 28, 30, 32). A microstrip feed line (40, 42, 44, 46) is formed by a metallization deposit on an opposing side of the substrate (22). The microstrip feed line (40, 42, 44, 46) extends across a narrow portion of the tapered slot (26, 28, 30, 32) and is configured to optimize the coupling between the microstrip feed line (40, 42, 44, 46) and the tapered slot antenna (20).

Extended dielectric material tapered slot antenna

Methods and systems for determining and utilizing spatial correlative information relating to two or more devices to determine device positioning are described. Using audio signals emitted from stereo speakers, for example, associated with a first device and a microphone associated with the second device, the distance and angle between the two devices and as their relative positions can be determined. No other sensors or specialized accessories are needed on either device to calculate the distance and angles. The devices need only be loaded with the appropriate software which, when executed, is able to carry out steps of the present invention. The usefulness of one or both of the devices may be enhanced by knowing the distance and angle data between the devices. For example, one device may be a TV having stereo speakers and the other device may be a handheld device, such as a smartphone, having a microphone.

Position determination of devices using stereo audio

Images of objects are obtained by microwave signal radiators and receptors which are disposed in a two dimensional array with the receptors disposed orthogonally to the radiators. The output of the receptors for illumination provided separately from each of the radiators is compared with reference microwave signals coherent with the radiated signals but varied cyclically in amplitude and phase. The results of the comparison are a plurality of outputs, which may be in digital form and which correspond to minimums in the power level of the difference signals obtained by comparison of the received signals and phase and amplitude varying reference signals. These outputs provide a two-dimensional interference pattern which can be translanted into a visual image of the object.

Method of and system for microwave interferometry

A radome diagnostic system comprises a rotatably mounted turntable having support memebers for supporting a radome in a radome support area on the turntable, and a scanning assembly on the turntable for supporting a probe antenna in the radome support area and for translating the probe antenna in perpendicular x and y directions to cover a predetermined planar scanning area. A reference antenna is mounted on the turntable to provide a reference signal, and both the reference antenna and the probe antenna are connected to a suitable receiver for receiving signals from them and for suitably analyzing the collected data. A transmitter is located at a position remote from the turntable to direct radiation towards a radome mounted on the turntable. The probe antenna will detect radiation as degraded or modified by the effect of the presence of the radome in the radiation path. The reference antenna receives unperturbed radiation.

Radome diagnostic system

A vehicle-mounted passive synthetic aperture system for locating sources of electromagnetic radiation having a given wavelength λ. The system includes first and second receiving antennas, a phase sensitive receiver and a signal processor. The first and second antennas are mounted to a vehicle and spaced apart from each other in the principle direction of motion associated with the vehicle. The first and second antennas respectively provide first and second received signals in response to a wavefront of electromagnetic radiation having the given wavelength λ. The phase sensitive receiver is coupled to the first and second antennas and responds to the first and second received signals by providing a phase difference signal that indicates a phase difference φ between the wavefronts of the radiation of the given wavelength received by the respective first and second antennas when the received radiation is radiated spherically from its source. The speed of the vehicle also is measured. The signal processor processes the phase difference signal in combination with the measured vehicle speed to provide imaging signals for an object-space display of an image of the source of the electromagnetic radiation in relation to the location of the vehicle. The image is displayed. The system of the present invention effectively uses the motion of the vehicle to synthesize an aperture. The synthesized aperture is long relative to the spacing between the receiving antennas (which spacing is limited by vehicle size) so that angular resolution is greater than that of a fixed antenna system with a baseline length equal to the spacing between the receiving antennas of the present system.

Passive synthetic aperture system for imaging a source of electromagnetic radiation

A method and apparatus for measuring radiant energy scattering characteristics of a test panel of dielectric material over a sphere are disclosed. The test panel is supported on a turntable at a position on the axis of the turntable. The turntable has a first antenna radially mounted thereon for rotation therewith and directed toward the position of the supported test panel. A second antenna is mounted for selective positioning along a circular arc within a plane that includes the axis of the turntable, which arc extends at least ninety degrees from said axis, wherein the second antenna is radially directed toward the position of a test panel that is axially supported on the turntable at all positions along said arc. The test panel support is rotated with respect to the turntable to selectively position the test panel at a predetermined incidence angle with respect to the first antenna. The turntable is rotated with respect to the second antenna to selectively position the test panel at an angle with respect to the axis of propagation of the second antenna that is equal to and opposite the predetermined incidence angle. Radiation transmitted between the first and second antenna is measured with the test panel in the supported position at each of a plurality of predetermined equal and opposite incidence angles with respect to the first and second antennas; and radiation transmitted between the first and second antennas is measured at each of the plurality of predetermined incidence angles when the test panel is not supported on the turntable. The second antenna is position at a plurality of positions along the circular arc at various ones of the predetermined incidence angles at which measurements are made as described above. Further measurements are made, both with the test panel in its supported position on the turntable and with test panel absent, of the radiation transmitted between the first and second antennas at the plurality of positions along the circular arc at the various ones of the predetermined incidence angles. The reflectance characteristics of the test panel are then determined by subtracting the measurements taken without the test panel in place from those taken with the test panel supported on the turntable.

Three-dimensional measurement of radiant energy scattering characteristics with a turntable-type scanning interferometer

A passive system and method for enabling the display of an image of the location of emitters of electromagnetic radiation that is effective in the lower portion of the HF band. The system essentially includes an array of antennas for receiving electromagnetic radiation from emitters, and for providing a received signal from each emitter in response to the received radiation; a receiver system coupled to each antenna of the array for measuring the phase and intensity of each received signal, and for providing separate coherent phase signals and amplitude signals that respectively indicate the measured phase and intensity; and a signal processor coupled to the receiver system for processing the coherent phase signals and amplitude signals to provide an image signal for generating an image of the emitters. A display device, such as a cathode ray tube or a graph plotter, is coupled to the signal processor for displaying the image of the location of the emitters in response to the image signal.

Eugene L. Rope

Papers

Method of and system for microwave interferometry

Radome diagnostic system

Passive synthetic aperture system for imaging a source of electromagnetic radiation

Three-dimensional measurement of radiant energy scattering characteristics with a turntable-type scanning interferometer

Determining the location of emitters of electromagnetic radiation