Abstract: In a cellular telecommunications network, uplink interference, as measured by a base station in a target cell, and co-channel interference, as measured by mobile units in a co-channel cell are reduced by increasing the base station antenna tilt angle. However, increasing the base station antenna tilt angle reduces the effective coverage area of the target cell. To obtain an optimum base station antenna tilt angle, interference reduction and target cell coverage area reduction are quantified for each of a number of candidate base station antenna tilt angles. An interference reduction-to-target cell coverage area reduction ratio can then be established for each of the candidate base station antenna tilt angles. The optimum base station antenna tilt angle can then be identified as the one candidate base station antenna tilt angle that reflects the maximum interference reduction-to-target cell coverage area reduction ratio.

Abstract: A tracking system for maintaining an alignment between a reflector antenna and a source of electromagnetic radiation, includes a reflector for reflecting electromagnetic radiation generated from a electromagnetic radiation source, a receiver, and a rotary sub-reflector which is positioned in front of the reflector for deflecting the radiation reflected by the reflector to the receiver and for generating triggering signals for measuring the strength of signals of the reflected radiation, whereby the sub-reflector is arranged at an inclination with respect to the reflector by an offset angle.

Abstract: A novel means of scanning a circularly polarized reflectarray antenna. The reflectarray is an array of metallic elements arranged on a surface designed to compensate for the various path lengths of the optical rays from an illuminating feed to the reflecting surface and then to the antenna aperture. With appropriate design, the phase in the aperture can be made to vary linearly in any desired direction and also to produce a radiated beam normal to the constant phase surface. In the case of circular polarization, this path length compensation can be accomplished by rotation of the individual elements.

Abstract: An optical reflector antenna utilizes a subreflector that is offset from the optical axis of the antenna and that revolves about the optical axis to scan the beam from the antenna in a circular path about the axis of the antenna to facilitate the search for and acquisition of a satellite for subsequent tracking and communications. The subreflector is mounted on a rotatable shaft that is aligned with the optical axis of the antenna. When the shaft is not being rotated, one or more springs hold the subreflector in a fixed position aligned with the optical axis of the antenna to facilitate tracking and communications. When the shaft is rotated, rotational forces cause the subreflector to shift to and remain at a position that is offset from the optical axis and the rotation of the shaft causes the offset subreflector to revolve about the optical axis of the antenna, thus scanning the beam from the antenna to facilitate the search for and and the acquisition of the satellite.

Abstract: An electronically scanned antenna that is manufactured using semiconductor material and device fabrication technology. The antenna has a semiconductor substrate having a plurality of stubs projecting from one surface. The semiconductor substrate may be silicon, gallium arsenide, or indium phosphide, for example. A first conductive layer formed on the surfaces of the semiconductor substrate and along sides of the stubs so that the stubs are open at their terminus. The conductive layers form a parallel plate waveguide region. A diode array having a plurality of diode elements is formed in the semiconductor substrate that are disposed transversely across the semiconductor substrate and longitudinally down the semiconductor substrate between selected ones of the plurality of stubs. The diode array may comprise an array of Schottky or varactor diodes, for example.

Abstract: Methods for estimation of the relative locations (baseline vectors) of two or more GPS signal antennas relative to each other and for estimation of line biases associated with each signal processing channel associated with each GPS signal antenna. Double difference carrier phase signal measurements are formed, using floating integer and fixed integer solutions for the phase integer ambiguities, and baseline vectors between the GPS signal antennas are estimated. Single difference phase integer ambiguities are obtained and approximations for line biases are computed. Single difference carrier phase measurements are used to estimate baseline vectors and line biases, using fixed phase integer ambiguities with the estimated baseline vectors and line biases as initial conditions, and are processed by Kalman filtering or other suitable signal processing. Angular orientation or attitude of a vehicle body on which the GPS signal antennas are placed is determined from the baseline vectors.

Abstract: A wireless telecommunication antenna mount has a platform which carries a plurality of antennas. The platform is mounted on a pedestal in an angularly adjusted position. The pedestal is mounted on the top of an electric power transmission tower in a position above the tower.

Abstract: The present invention provides a method and apparatus for expediently determining the azimuthal orientation of a total station. In one embodiment, the present invention is comprised of a total station having a vertical axis. The total station also includes a rotational alidade portion adapted to rotate about the vertical axis, and an electronic distance measuring portion. The present invention also includes a satellite-based position determining system antenna coupled to the total station. In the present invention, the satellite-based position determining system antenna is offset from the vertical axis. That is, in the present invention, the satellite-based position determining system antenna is not disposed coincident with the vertical axis of the total station.

Abstract: A beam steering control for a mobile satellite communications antenna, includes an antenna having a steering mechanism; a dynamic rate sensor for producing a signal related to the rate of change of position of a vehicle to which the antenna is mounted; and a control system for controlling the steering mechanism, the control system including a satellite tracking loop, an inertial stabilization loop, a calibration algorithm for dynamically calibrating the rate sensor, and a satellite acquisition algorithm for determining a azimuth angle of the antenna relative to an inertial reference.

Abstract: A two-axis satellite antenna mounting and tracking assembly including a universal joint for mounting the antenna to support structure. A pair of linear actuators offset at 90.degree. to each other about the universal joint are operated in full-on/full-off fashion to control the azimuth and elevation orientations of the antenna. Satellite tracking is effected by maximizing received signal strength.

Abstract: A computer vision system is disclosed that utilizes a spinning array of podetectors. The array is rotated about the focal plane of a lens and scans all the possible orientations and positions of the edges of the unknown object. In one embodiment, the photodetectors are elongated so as to provide for maximum light gathering ability along the direction of elongation and a minimum light gathering ability in the direction perpendicular to the direction of elongation. In other embodiments, optical means are used to focus the image onto conventional photodetectors while still having the ability to more efficiently determine edge segments of unknown objects. The system efficiently and rapidly implements the wavelet projection transform to characterize-multi-scale edge segment features of an image of an unknown object. An imaging radar system that utilizes a spinning antenna system having frequency scanning provisions is also disclosed.

Abstract: A steerable antenna system for adjusting the elevation of an antenna for communication with a central facility via a satellite. The steerable antenna system includes a motor, a spindle drivingly engaged to the motor, and a chassis fixedly disposed on the spindle. The chassis has a stop disposed about its periphery. A first waveguide is fixedly disposed on the chassis and a second waveguide is disposed on an antenna. A ring cam is mounted on the chassis, and a grooved is formed in the ring cam. A first portion of a lever arm is pivotally mounted on the chassis and a second portion of the lever arm is disposed in the groove of the ring cam. An antenna is hingedly mounted on the chassis and to the lever arm. A solenoid, disposed on a base of the steerable antenna system, is configured to engage a portion of the ring cam. In use, when the solenoid is activated, power from the motor is used to adjust the elevation of the antenna.

Abstract: Systems and methods for thermal imagining are described. An apparatus includes a rotatable radial scanning antenna. The systems and methods provide advantages in that fires can be detected, and their positions determined, over substantial distances and through obscurants such as smoke and/or rain.

Abstract: A microwave antenna device on PCMCIA network cards for notebook computers includes; extended base, which is connected to input port of PCMCIA network card, has pivot acceptor symmetrically located on the outer side of extended base, T-shaped pivot which is capable of 180-degree rotation about the vertical axis, is then supported by pivot acceptor. Tunnel is inside pivot and extended base, in which HF (high frequency) transmitting wire from input port passes through up to the top of pivot. Plate which is capable of 90-degree rotation in both clockwise and counter-clockwise direction is hooked up on pivot. Plate which is capable of 90-degree rotation in both clockwise and counter-clockwise direction is hooked up on pivot. Plate or bar microwave antenna is capped on pivot and connected through HF transmitting wire. In accordance with the above description, plate microwave antenna has the advantage of foldable for transportation easy to setup, receiving angle optimisable and preventing from breaking design.

Abstract: An antenna is shaped to provide a predetermined contour and is mounted for universal movement on its support. An electronically controlled drive mechanism is operatively associated with the antenna to rotate the antenna to preselected positions corresponding to specific target locations. A fixed feed horn excites the antenna to generate a first radiation pattern which conforms to the shape of a primary desired target location when the antenna is moved to a first position and a second radiation pattern which conforms to the shape of a secondary desired target location when the antenna is moved to a second position. By further designing the antenna shape, multiple contoured beams for multiple target locations are obtained.

Abstract: An antenna dish system for tracking satellites includes an antenna dish having peripheral edges. A tripod stand has first and second front legs and a rear leg. An apex is formed by the interconnection of the two front legs and the rear leg. A first linear actuator is mounted on the first front leg and has an output shaft connected to a peripheral edge of the antenna dish. A second linear actuator is mounted on the second front leg and has an output shaft connected to a peripheral edge of the antenna dish. A universal joint is positioned at the apex of the tripod stand and mounts the antenna dish to the tripod stand. The universal joint constrains rotation of the antenna dish about the normal axis, but allows pitch and yaw motion of the antenna dish. A controller is connected to the first and second linear actuators for controlling their output shafts and enabling controlled motion of the antenna dish, such as for tracking satellites.

Abstract: An antenna unit comprises at least one base mount metal member fixed to a strut; a fixing structural portion for rotatably fixing the at least one base mount metal member to the strut so as to be capable of rotating around the strut; an antenna integral-type radio transmitter-receiver apparatus fixed to the base mount metal member; and an elevation adjustment mechanism for adjusting an elevation of the antenna integral-type radio transmitter-receiver apparatus. An azimuth adjustment of the antenna integral-type radio transmitter-receiver apparatus is carried out by rotating the base mount metal member together with the antenna integral-type radio transmitter-receiver apparatus around the strut.

Abstract: A phased array antenna having stacked-disc radiators embedded in dielectric media. The phased array antenna has a rectangular arrangement of unit cells that are disposed on a ground plane. A lower dielectric puck with a high dielectric constant is disposed on the ground plane. An excitable disc is disposed within the perimeter of and on top of the lower dielectric puck. An upper low dielectric constant dielectric puck that has a dielectric constant lower than that of the lower dielectric puck is disposed on the excitable disc. A parasitic disc is disposed within the perimeter of and on top of the upper dielectric puck. Dielectric filler material having a dielectric constant that is lower than that of the lower dielectric puck surrounds the dielectric pucks. A radome 18 is disposed on top of the parasitic disc and the unit cell. Two orthogonal pairs of excitation probes are coupled to the lower excitable disc.

Abstract: A positioner includes an output platform and a two axis bearing-suspension which permits the output platform to rotate about two orthogonal axes. The output platform is positioned by a pair of actuators which are mounted, as is the bearing suspension, to a positioner base. The actuators include bevel gears which engage ratchets to couple the actuators and the platform.

Abstract: The radio frequency unit of a millimeter wave terrestrial radio includes a housing with a front face and a back face, a microwave radio frequency transceiver electronics package within the housing, an antenna affixed to the front face of the housing, and appropriate signal connections and feeds. One portion of a dovetail support structure, preferably the male dovetail fitting, is affixed to the back face of the housing. The other portion of the dovetail support structure, preferably the female dovetail fitting, is mounted to a mounting structure. The dovetail support structure allows the radio frequency unit to be readily mounted to and demounted from the mounting structure. A reference plane defined between the radio frequency unit and the mounting structure allows the radio frequency unit to be precisely oriented relative to the mounting structure.

Abstract: Dual-axis hinge assemblies comprising mechanical devices which provide integrated synchronous rotation of a support element, such as a space antenna shaft, attached to a vertical hinge shaft about its own axis while simultaneously pivoting the support shaft about a horizontal hinge shaft having a second axis which extends in a direction perpendicular to the axis of the vertical hinge shaft. The hinge assembly is adapted to be mounted parallel to a side surface of a spacecraft body and restrained by a holddown device, and is biased to cause the space antenna to pivot on the horizontal hinge shaft from restrained position to deployed position and to simultaneously turn on its own axis about a vertical hinge shaft when the restraint is removed, to aim the antenna reflector disk in a predetermined direction.

Abstract: A mobile tracking antenna for microwave signals from a satellite or distant transmitter includes a micro- electromechanical system produced by semiconductor processing. Specifically several micro faceted reflector segments have their facets selectively controlled by a feedback control system and reflects the signal onto a four sector horn which then by error signals actuates electrostatic positioning means on the micro facets to center the signal on the optimum receiving portion of the horn. Each segment covers a portion of the 360.degree. receiving spectrum. The particular segment is selected by a maximum signal being received.

Abstract: An integrated point-to-point microwave radio frequency unit/antenna system includes a microwave transceiver/antenna unit, a housing support element affixed to the microwave transceiver/antenna unit, and a mounting structure support element engaged to the housing support element. The mounting structure support element includes a fixedly adjustable ball-and-socket element, with either the ball or the socket affixed to the housing support element and the other affixed to an attachment structure. The mounting structure support element permits the microwave transceiver/antenna unit to be adjusted in three degrees of freedom.

Abstract: A mobile satellite communication system includes an antenna assembly mountable on a vehicle and a satellite tracking assembly. The antenna assembly includes an antenna device for receiving first satellite signals from a first satellite in a first frequency band and for transmitting and receiving second satellite signals to and from a second satellite in a second frequency band, and a drive subassembly for rotating the antenna device relative to the vehicle in response to a control signal. The satellite tracking assembly maintains the antenna device pointed at the first and second satellites as the vehicle moves. The system further includes a receiver coupled to the antenna device for receiving the first satellite signals and a transceiver coupled to the antenna device for transmitting and receiving the second satellite signals. The first satellite signals may be video and imagery data signals transmitted in the Ku band by a direct broadcast satellite.

Abstract: Systems that distribute live television programs to passengers of an aircraft by way of satellites of a direct broadcast satellite (DBS) system when the aircraft is in range of the satellites and distributes time-delayed television programs when the aircraft is out of range of the satellites. The present invention provides for real-time reception and storage of live television programs in a storage medium (in compressed digital format) and presentation to passengers during that time when the aircraft is within the coverage area of satellites. The stored programming is distributed to the passengers later in the flight, when the aircraft is out of range of the satellites. The stored programming includes all channels transmitted by the satellites. Thus, a large number of programs are made available to the passengers on a time-delay basis. A low-cost system is disclosed that distributes a single television channel to overhead monitors and headphones.

Abstract: A system that provides live television programming to passengers by integrating direct broadcast satellite services into an in-flight aircraft entertainment system. The present invention is a satellite television system that has an antenna disposed on the aircraft that is pointed at a plurality of satellites that are part of a direct broadcast satellite system. The antenna is controlled by an antenna controller and antenna interface unit that send control signals and process status signals to steer the antenna. The antenna is steered to lock it onto RF signals transmitted by the satellites. The antenna interface unit downconverts the received RF signals to provide left hand circularly polarized RF signals and right hand circularly polarized RF signals that contain different sets of television channels. The downconverted RF signals are processed by a receiver/decoder that decodes them to provide video signals corresponding to different television channels.

Abstract: A satellite television system that provides live television programming to passengers by integrating direct broadcast satellite services into an in-flight aircraft entertainment system. The system has an antenna disposed on the aircraft that is pointed at a plurality of satellites that are part of a direct broadcast satellite system. The antenna is controlled by an antenna controller and antenna interface unit that send control signals and process status signals to steer the antenna. The antenna is steered to lock it onto RF signals transmitted by the satellites. The antenna interface unit downconverts the received encoded RF signals to provide encoded left hand circularly polarized RF signals and right hand circularly polarized RF signals that contain different sets of television channels. The downconverted encoded RF signals are processed by a receiver to provide encoded video and audio signals of different television channels. The receiver does not decode or D/A convert the downconverted signals.

Abstract: A method and apparatus for aiming a satellite dish includes an adjustable gnomon. The adjustable gnomon is calibrated. Using setting information generated by computer softwvare, a user sets the gnomon according to the calibration numbers returned by the computer software. The user then lock the setting into place. After locking the gnomon into position, the user employs the gnomon to aim a satellite dish or other directional antenna. Aiming the antenna requires aligning the antenna such that a shadow cast by the gnomon substantially coincides with a predetermined target.

Abstract: A tracking antenna for non-geostationary satellites is mounted on a three-axis positioner comprising an azimuth axis, an elevation axis mounted perpendicularly on the azimuth axis and a pseudo-azimuth axis mounted perpendicularly on the elevation axis and supporting the antenna. The positions of the axes are controlled by a pointing unit. The method of pointing the antenna carries out the following steps simultaneously when the position of the satellite is such that the elevation axis exceeds a predetermined elevation value: modifying the position of the azimuth axis at constant speed and modifying the position of the elevation axis and the pseudo-azimuth axis to track the satellite.

Abstract: A device for scanning in a scanning axis includes a periodic array of conductive plates disposed along the scanning axis. The device has a periodic array of ferroelectric material slabs disposed along the scanning axis, each slab being disposed between a pair of adjacent conductive plates, adjacent slabs being separated by one of conductive plates. Each of the slabs has a receiving face and a radiating face substantially parallel to each other. Input transmission means feed an input electromagnetic signal to the periodic array of slabs in a propagation direction so that the input electromagnetic signal is incident on the receiving faces of the slabs and so that the electrical component of the input electromagnetic signal received at each receiving face has a component parallel to the scanning axis.

Abstract: A method and a device are disclosed relating to the stabilization of mechanical bodies. The method is based on supporting the body to be stabilized at its mass center, whereby no acceleration in any direction causes a torque induced by the inertial forces in the body. The body thus maintains its position in relation to the earth gravity field, even if accelerations and various kinetic states were effective at the point of support. Inching of the body from the desired position is compensated by a slow control system using actuators functioning on a contact-free principle. As a particularly advantageous embodiment, the invention can be applied for stabilizing bodies attached to moving objects.

Abstract: An apparatus is disclosed which computes the full-step number of full-step drive pulses at each control period, generates microstep drive pulses on the basis of the full step number so as to make a drive angle at each control period correspond to a full-step unit, and drives a motor drive current on the basis of the microstep drive pulses.

Abstract: A small aperture satellite ground station communications antenna is disclosed. A rectangular section of a curved parabolic reflector is provided having first and second rectangular dimensions. An azimuth elevation pedestal for positioning the reflector is provided such that the antenna bore sight is aligned with a geostationary satellite. The reflector is supported by the pedestal to permit rotation of the reflector about a third polarization axis for the antenna. The rotation along the polarization axis permits the reflector to be optimally positioned such that its long dimension is aligned with an orbital arc of a geostationary satellite. Angle scales are provided on all three axes to facilitate repositioning to other satellites based on an initial satellite location, which serves as a reference for the scales.

Abstract: A base support for a moveable antenna. The base support is attached to an upstanding mounting member and the antenna is attached to a support structure connected to a base member. The support structure is operatively connected to a worm gear assembly which includes a motor driven worm and worm gear disposed between the base member and support structure to effect movement of the antenna about a predetermined axis. The motor driven worm is supported at an outboard end by a first bearing assembly and supported at its opposite end by a pair of spaced apart bearing assemblies to prevent backlash between the motor driven worm and worm gear. A second worm gear assembly including a similarly supported motor driven worn and worm gear can be interposed transversely between the first support structure and a second support structure to effect movement of the antenna about a horizontal axis.

Abstract: A tracking array antenna system is provided. When a signal from the target is received normally, control mode of an AZ axis and an electronic XEL axis is changed over according to whether or not a moving platform is inclined about the XEL axis for detecting inclination of the moving platform. When the moving platform is not inclined, beam-switch (BSW) about the electronic XEL axis is performed, and the beam-switch tracking (BST) about the AZ axis using the result with an angular rate feedback (ARFB) is performed. When the moving platform is inclined, zero rate control (ZRC) about the AZ axis and BST about the electronic XEL axis are performed. In this way, tracking and stabilization are performed without not only the gimbal-lock but also the use of a gyrocompass.

Abstract: A positioning device orients an antenna element, or an entire antenna of multiple elements, or other payload requiring positioning relative to a supporting base. The antenna element is pivotally mounted upon the base, and a strut extends from the antenna element to an actuator assembly which moves the strut to adjust the orientation of the antenna element. The actuator assembly has two linear actuators which extend from the base, respectively, to opposite ends of a lever which, in turn, connects via a pivot to an end of the strut distant from the antenna element. The lever pivot is located between the ends of the lever at a location closer to one of the ends than to the other of the ends of the lever, such as a two-to-one ratio of lever arm lengths. Use of a first of the actuators by itself serves for the primary source of adjustment of the position of the antenna element.

Abstract: A multi-loop control system for a gimballed antenna that employs devices for measuring both absolute line-of-sight (an autotrack receiver or beacon tracker) and relative angular position (a resolver). The control system uses both signals simultaneously, thereby increasing the performance and pointing accuracy capability. Two control loops operate simultaneously to provide for optimum performance. The first loop is an inner high-bandwidth control loop that uses the relative gimbal angle measurement to control pointing of the antenna along a precommanded profile. The inner loop may run alone to provide for coarse pointing. When available, the line-of sight measurement is used in a low-bandwidth outer loop to provide corrections to the command profile of the inner loop. Control logic is provided that allows switching between several control modes.

Abstract: A receiver (100) that includes an antenna (101) employs a method and apparatus for producing diversity gain of a signal (106) received by the antenna (101), wherein the signal (106) is subject to a time-variant fading condition. Upon receiving the signal (106), the receiver (100) determines a signal quality metric of the signal (106) and compares the signal quality metric to a quality threshold. When the signal quality metric is below the quality threshold, the receiver (100) orients a predetermined antenna pattern (304) of the antenna (101) to improve the signal quality metric, thereby producing the diversity gain.

Abstract: The invention relates to a device for positioning antennas, the device comprising an assembly having an antenna-carrier mast movably mounted in a reserve provided between a particular absorbent wall of the measurement chamber and the adjacent wall of the envelope of the chamber; the mast passes through the particular wall via an associated slot to extend into the measurement chamber, each antenna is mounted to slide along the mast without interfering mechanically with any other antenna carried by the mast, thereby making it possible to position a desired antenna at a desired location while retracting the other antennas inside the reserve, behind the above-mentioned particular wall.

Abstract: A direction adjustment indicator for a satellite radio wave receiving antenna comprises a demodulating circuit to demodulate a satellite radio wave received by the antenna, a peak holding circuit always to output a held peak value of the demodulated output of the demodulating circuit, a comparator circuit and a display element. The comparator circuit compares the instantaneous value of the demodulated output and the held peak value, and outputs a signal when both values are equal and another different signal when both values are not equal. The display element gives two different kinds of display in accordance with the signals. While the azimuth angle of the antenna is varied in one direction, a peak value of the demodulated output is held and while the angle is varied in the opposite direction, the optimum azimuth angle is displayed for which the instantaneous value of the demodulated output agrees with the held peak value.

Abstract: This plane array antenna for receiving satellite broadcasts is an optimal combination of the plane array antenna main body having a tilt angle, a converter connected with the antenna main body through the power supply portion, and the rotation mechanism for rotating the antenna main body within almost a horizontal plane for tracking the azimuthal angle direction. The plane array antenna main body has the power supply portion formed at the center of the rotation and the converter includes a dielectric substrate having a microstrip channel formed on the substrate and a casing accommodating the substrate. The converter is fixed downwardly of the antenna main body and supports the antenna main body. The power supply portion includes the power supply probe with an insulation covering, and has its front end portion inserted into a space formed with the antenna body, a central portion extending through the casing of the converter, and the lowest end portion combined with the microstrip channel.

Abstract: A reflecting mirror-equipped GPS receiving antenna apparatus comprises a reflecting mirror and a microstrip type of antenna for receiving radio waves transmitted from GPS satellites. The reflecting mirror is supported by a base member so as to be swingable about a horizontal axis as well as rotatable about a first vertical axis. The antenna is supported above the reflecting mirror so as to be rotatable about a second vertical axis which is coaxial with the first vertical axis.

Abstract: A base support for a moveable antenna employing a stepping motor and stepping motor controller to move the antenna in fine increments. The base support is attached to an upstanding mounting member. An antenna is attached to a first support structure connected to a base member. The support structure is operatively connected to a worm gear assembly and motor driven worm gear disposed between the base member and the support structure to effect movement of the antenna about a predetermined axis. The worm gear is driven by a stepping motor. The stepping motor is controlled by a stepping motor controller to control incremental movement of the antenna. A second worm gear assembly can be interposed transversly between the first support structure and a second support structure to effect movements of the antenna about a horizontal axis. A second stepping motor and second stepping motor controller are used to drive the second worm gear and effect incremental movement of the antenna about the horizontal axis.

Abstract: A receiver connected to the satellite dish antenna receives signals from an electronic compass for generating a magnetic direction signal. The approximate latitude and longitude values of the parked vehicle are displayed and the user of the system manually selects the latitude and longitude coordinates corresponding to the parked vehicle location. The receiver determines an initial search position for the satellite dish antenna based upon the magnetic reading and the entered latitude and longitude values. The satellite dish antenna is moved from an unstowed position to an initial search position. The satellite dish antenna is then moved in a first rectangular spiral search pattern to obtain a rough-tune position corresponding to the detection of a signal peak for a selected audio subcarrier frequency in a selected channel of a target satellite. The frequency selected is not present in corresponding selected channels of satellites near the target satellite.

Abstract: A stabilized antenna system is installed on a moving platform such as a ship to track a communication satellite. The antenna system examply employs either X1-Y-X2 or Y1-X-Y2 antenna mount. Rolling and pitching of the moving platform are offset by mechanically steering outside and intermediate axes, X1 and X, or Y1 and Y axes. The innermost axis is electronically steered to prevent instability which is caused by the mechanical steering, thereby improving reliability of the antenna system. The frame for rotatable supporting the array antenna is also supported by the radome rotatably. Further, the access hutch for maintainance is opened at the center of the radome and just below the array antenna.

Abstract: A satellite television receiver antenna for use on seaborne vessels comprises a Cassegrain antenna including a parabolic main reflector, and a hyperbolic sub-reflector mounted at an angle slightly opposite from the center axis of the parabolic reflector, the sub-reflector being driven by a motor to rotate so as to cause the antenna reception pattern to perform a conical scan around the main axis of the parabolic reflector. The rotational speed is an even multiple of the frequency of any amplitude modulation of the received signal, or of any electrical interference, and the received signal is measured at points rotationally spaced apart 180 degrees, so that the effects of modulation and/or electrical interference are cancelled. The measured signal strength at four positions spaced rotationally by 90.degree. is used to derive power signals to drive pulse width modulation control azimith and elevation motors.

Abstract: An embodiment of the present invention is a system for automatically pointing a directional antenna. The system comprises two GPS antennas mounted at horizontally opposed extremities of the directional antenna, the placement is such that the GPS antennas lie on a line having a normal vector approximately parallel to a boresight of the directional antenna. The outputs from the GPS antennas are downconverted to a measurement frequency and differentially phase compared for each of a plurality of radio visible GPS satellites. A measurement controller that receives the phase comparisons. A navigation computer receives measurements from the measurement controller and uses a microprocessor to calculate the GPS latitude and longitude and the attitude angles of the pair of GPS antennas. A servo points the directional antenna at a particular target communications satellite, based on the computed azimuth, elevation, latitude, and longitude, as provided by the navigation computer.

Abstract: A receiver connected to the satellite dish antenna receives signals from an electronic compass for generating a magnetic direction signal. The approximate latitude and longitude values of the parked vehicle are displayed and the user of the system manually selects the latitude and longitude coordinates corresponding to the parked vehicle location. The receiver determines an initial search position for the satellite dish antenna based upon the magnetic reading and the entered latitude and longitude values. The satellite dish antenna is moved from an unstowed position to an initial search position. The satellite dish antenna is then moved in a first rectangular spiral search pattern to obtain a rough-tune position corresponding to the detection of a signal peak for a selected audio subcarrier frequency in a selected channel of a target satellite. The frequency selected is not present in corresponding selected channels of satellites near the target satellite.

Abstract: The antenna particularly for domestic, collective or community installations, receives plural telecommunication beams and comprises a preferably paraboloidal fixed reflector with an axis of symmetry. At least one grating of annular diffraction members is substantially symmetrical with regard to the axis and is placed parallel to the reflector. The grating defines first and second focal points symmetrical to the axis towards which are susceptible to converge first and second beams directed substantially parallel to straight lines going through the centre of the grating and through first and second focal points respectively. A microwave head can sweep the focal plane along a focal line, or several microwave heads are positioned on a gantry thereby receiving or emitting plural beams, though the reflector is fixed.

Abstract: Disclosed is an apparatus and method for shaping a beam of radiation from a circularly polarized beam shaping antenna to create a predetermined radiation pattern. A circularly polarized feed horn generates the beam of radiation to be shaped. Circularly polarized radiator elements attached to a ground plane are positioned to receive the beam of radiation. Each radiator element is physically rotated about an axis relative to the ground plane to alter its phase. The radiator elements are then operable to individually radiate a beam of radiation to form a combined radiation beam creating the predetermined radiation pattern.