Abstract: Antenna system includes an axially symmetric ground plane; a circular disc patch radiator positioned parallel to the ground plane; and a circular ring patch radiator positioned parallel to the ground plane and shorted to the ground plane using a cylindrical conductor at its inner radius; both radiators have the common axis of rotational symmetry; each radiator is excited with its own vertical metal pin, and both radiators are located at same height above the ground plane; and an axially symmetric capacitive decoupling element connecting a center of the disc patch to a center of the ground plane. Each vertical metal pin goes through the ground plane using through holes, and each vertical metal pin has a impedance matching network connected to it, and wherein the impedance matching network is connected to its transmission line section. The disc patch and the ring patch are isolated from the ground plane with dielectric.

Abstract: A vehicular positioning system utilizing multiple optical cameras having contiguous fields of view for reading coded markers having pre-determined positions for determining the position of vehicle inside a structure with a high degree of accuracy. The vehicle positioning system provides for the direct installation and use of a positioning apparatus on a vehicle with a limited number of coded markers to determine the vehicle's position to within millimeter level accuracy.

Abstract: An antenna system includes a right-hand circularly polarized antenna for receiving Global Navigation Satellite System (GNSS) signals and located on a receiver housing; a vertical semitransparent screen for providing an Down/Up ratio DU 9 ? 0 = DU ? ( ? e = 9 ? 0 ? ) = F ? ( - 9 ? 0 ? ) F ? ( 9 ? 0 ? ) of ?13 dB or better for at least some GNSS frequencies; the semitransparent screen being connected to a ground plane of the antenna; the ground plane being connected to a conductive receiver housing; the semitransparent screen further comprising a horizontal slot to which sets of lumped impedance elements are connected. Each set includes several lumped elements; where the lumped elements are capacitors and/or inductors and/or resistors; where the lumped elements in each set are connected in parallel or series; and the semitransparent screen including at least 4 segments arranged symmetrically around the center of the antenna and connected to each other.

Abstract: A GNSS-UHF antenna, including a first PCB having four sets of radiating elements, a second PCB below the first PCB, a metal plate below the second PCB, which form a quadrifilar helical antenna for operating with right-hand circularly polarized GNSS signals and simultaneously form a monopole antenna for operating with linearly polarized UHF signals; for each set of radiating elements, a corresponding downward-extending conductor connected to the second PCB at a first end and connected to the set of radiating elements at a second end through an inductor; a first coaxial cable outputting GNSS signals; the first cable includes a partial loop between the second shield and the metal plate; and a second cable outputting the UHF and its braiding connected to the metal plate.

Abstract: A GNSS-UHF antenna, including a first PCB having four sets of radiating elements, a second PCB below the first PCB, a metal plate below the second PCB, which form a quadrifilar helical antenna for operating with right-hand circularly polarized GNSS signals and simultaneously form a monopole antenna for operating with linearly polarized UHF signals; for each set of radiating elements, a corresponding downward-extending conductor connected to the second PCB at a first end and connected to the set of radiating elements at a second end through an inductor; a first coaxial cable outputting GNSS signals; the first cable includes a partial loop between the second shield and the metal plate; and a second cable outputting the UHF and its braiding connected to the metal plate.

Abstract: An antenna system includes a right-hand circularly polarized antenna for receiving Global Navigation Satellite System (GNSS) signals and located on a receiver housing; a vertical semitransparent screen for providing an Down/Up ratio DU 9 ? 0 = DU ? ( ? e = 9 ? 0 ? ) = F ? ( - 9 ? 0 ? ) F ? ( 9 ? 0 ? ) of ?13 dB or better for at least some GNSS frequencies; the semitransparent screen being connected to a ground plane of the antenna; the ground plane being connected to a conductive receiver housing; the semitransparent screen further comprising a horizontal slot to which sets of lumped impedance elements are connected.

Abstract: A GNSS compact antenna comprising a conducting ground plane and a driven element for exciting right hand circularly polarized waves having a multi-segment structure such that the area around the driven element is divided into elementary cells with conductors and circuit elements arranged therein. The antenna includes a set of circuit elements connecting the neighboring elementary cells and the driven element. Each elementary cell has a horizontal conductor over the ground plane, and each elementary cell can have a vertical conductor and a circuit element connecting the horizontal and vertical conductors. The horizontal conductor comprises a set of characteristic points to which circuit elements, connecting neighboring elementary cells or any elementary cell and the driven element, are connected. Both the impedance of each circuit elements and the design of each elementary cell can be different, but the antenna has four-fold rotational symmetry relative to the vertical axis.

Abstract: A GNSS compact antenna comprising a conducting ground plane and a driven element for exciting right hand circularly polarized waves having a multi-segment structure such that the area around the driven element is divided into elementary cells with conductors and circuit elements arranged therein. The antenna includes a set of circuit elements connecting the neighboring elementary cells and the driven element. Each elementary cell has a horizontal conductor over the ground plane, and each elementary cell can have a vertical conductor and a circuit element connecting the horizontal and vertical conductors. The horizontal conductor comprises a set of characteristic points to which circuit elements, connecting neighboring elementary cells or any elementary cell and the driven element, are connected. Both the impedance of each circuit elements and the design of each elementary cell can be different, but the antenna has four-fold rotational symmetry relative to the vertical axis.

Abstract: A vehicular positioning system utilizing multiple optical cameras having contiguous fields of view for reading coded markers having pre-determined positions for determining the position of vehicle inside a structure with a high degree of accuracy. The vehicle positioning system provides for the direct installation and use of a positioning apparatus on a vehicle with a limited number of coded markers to determine the vehicle's position to within millimeter level accuracy.

Abstract: A vehicular positioning system utilizing multiple optical cameras having contiguous fields of view for reading coded markers having pre-determined positions for determining the position of vehicle inside a structure with a high degree of accuracy. The vehicle positioning system provides for the direct installation and use of a positioning apparatus on a vehicle with a limited number of coded markers to determine the vehicle's position to within millimeter level accuracy.

Abstract: A broadband quadruple helical circularly-polarized antenna for receiving circularly polarized GNSS signals includes a dielectric cylinder oriented along a vertical axis; four spiral conductors wrapped around the cylinder; the four spiral conductors divided into an upper longitudinal section and a lower longitudinal section; and inductors connecting corresponding spiral conductors of the top and lower longitudinal sections. The spiral conductors in each section have a constant winding angle around the cylinder. The winding angle of all of the conductors in the same longitudinal section is the same. The winding angle of the upper longitudinal section is smaller than the winding angle of the bottom longitudinal. An excitation circuit is connected to the conductors. A third longitudinal section is below the lower longitudinal section, wherein the third longitudinal section includes conductors wound in an opposite direction relative to the lower longitudinal section.

Abstract: An antenna system for a global navigation satellite system reference base station is disclosed. The antenna system includes an antenna positioned above a high capacitive impedance surface (HCIS) ground plane. Over a specific range of the lateral dimension of the HCIS ground plane and the height of the antenna above the HCIS ground plane, a high level of multipath suppression and high sensitivity for low-elevated satellites can be simultaneously maintained. The HCIS ground plane can be fabricated as a flat conducting plate with an array of conducting elements such as pins, pins with expanded tips, or mushroom structures. Alternatively, the HCIS can be fabricated as a flat conducting plate with a concentric series of choke rings. The antenna system can provide a positioning accuracy of +/?1 mm, an order of magnitude improvement over previous designs.

Abstract: A right-hand circularly-polarized patch antenna comprising a ground plane and a patch connected to each other with one or more wires for which the wire shape and location of the end points are selected such that they do not cause an antenna mismatch, and the electrical current carried in the wires produces an extra electromagnetic field subtracted from the patch field in the nadir direction.

Abstract: A right-hand circularly-polarized patch antenna comprising a ground plane and a patch connected to each other with one or more wires for which the wire shape and location of the end points are selected such that they do not cause an antenna mismatch, and the electrical current carried in the wires produces an extra electromagnetic field subtracted from the patch field in the nadir direction.

Abstract: An antenna system includes a circularly-polarized antenna element with a Down/Up ratio in a proximity of a local horizon of no better than ?12 dB. An antenna radome encloses the antenna element, the radome providing a drop of antenna pattern near a local horizon and having an upper transparent area and a lower semi-transparent area. The semi-transparent area is has a generally hemispherical shape. The semi-transparent area includes a circular metallized portion with vertical and horizontal slots, the metallized portion extending part of the way downward from an equator of the generally hemispherical shape. The metallized portion includes passive discrete electrical elements connected across at least some of the slots. The metallized portion can include multiple areas having different degrees of transparence. Each such area has a specified impedance. The discrete elements are capacitors, inductors and/or resistors. The metallized portion can have a plurality of circular rows separated by the horizontal slots.

Abstract: An antenna system includes an electromagnetic radiator assembled on a ground plane. The ground plane containing a nontransparent area in a center of the ground plane and a semitransparent area surrounding the nontransparent area. The nontransparent area is circular in shape. The semitransparent area is generally circular in shape and contains at least one slot. A plurality of vertical conducting elements are in proximity of a boundary between the nontransparent area and the semitransparent area on a bottom side of the ground plane. The vertical conducting elements are arranged in a circle around a center of the electromagnetic radiator.

Abstract: An antenna assembly includes a GNSS stacked patch antenna located in a metal cavity and a matching parasitic element, the matching parasitic element includes a set of conductors not connected to the antenna. Each conductor has an external end and internal end, the external ends being conductively coupled to the housing of the cavity. The conductors of the matching parasitic elements can be radially arranged. External ends of conductors are additionally connected to each other by a ring-shaped conductor. Internal ends of conductors can be connected to capacitive elements, which can be discrete capacitors and/or segments of conductors.

Abstract: A vehicular positioning system utilizing multiple optical cameras having contiguous fields of view for reading coded markers having pre-determined positions for determining the position of vehicle inside a structure with a high degree of accuracy. The vehicle positioning system provides for the direct installation and use of a positioning apparatus on a vehicle with a limited number of coded markers to determine the vehicle's position to within millimeter level accuracy.

Abstract: An antenna assembly includes a GNSS stacked patch antenna located in a metal cavity and a matching parasitic element, the matching parasitic element includes a set of conductors not connected to the antenna. Each conductor has an external end and internal end, the external ends being conductively coupled to the housing of the cavity. The conductors of the matching parasitic elements can be radially arranged. External ends of conductors are additionally connected to each other by a ring-shaped conductor. Internal ends of conductors can be connected to capacitive elements, which can be discrete capacitors and/or segments of conductors.

Abstract: A right-hand circularly-polarized patch antenna comprising a ground plane and a patch connected to each other with one or more wires for which the wire shape and location of the end points are selected such that they do not cause an antenna mismatch, and the electrical current carried in the wires produces an extra electromagnetic field subtracted from the patch field in the nadir direction.