31 results about "Antenna boresight" patented technology

A dual polarized variable beam tilt antenna having a superior Sector Power Ratio (SPR). The antenna may have slant 45 degree dipole radiating elements including directors, and may be disposed on a plurality of tilted element trays to orient an antenna boresight downtilt. The directors may be disposed above or about the respective dipole radiating elements. The antenna has a beam front-to-side ratio exceeding 20 dB, a horizontal beam front-to-back ratio exceeding 40 dB, a high-roll off, and is operable over an expanded frequency range.

A radar antenna has a reflector and maximum gain along its boresight. The reflector has a periphery, typically circular, rectangular or elliptical. A plurality of Global Positioning System (GPS) satellite signal receiving antennas are rigidly, mechanically attached to the reflector near its periphery. The plurality of GPS satellite signal receiving antennas are connected pairwise to a phase comparator for comparing a plurality of first phase differences induced by a first GPS satellite signal received concurrently between the plurality of GPS satellite signal receiving antennas. A Phase comparator measures the phase difference of the signal received at GPS satellite signal receiving antennas pairwise thus performing a differential phase measurement. This differential phase measurement is supplied to a computer for identifying an ambiguous boresight position using the phase differences measured by the phase comparator. The position of the GPS satellites is known with respect to the geo-location of the antenna. Thus, the boresight angle is derived from the phase difference of the carrier signal from the GPS satellite being received and the mechanical alignment information between the GPS satellite receiving antennas and radar antenna boresight stored during calibration / manufacture of the radar antenna. The ambiguity in the computed boresight position is resolved by making differential phase readings using the same GPS antennas from a second GPS satellite signal supplied by a second satellite.

A system and method for increasing the performance of a satellite communication system by using a multivariate analysis approach to optimize the pointing of the boresight of a satellite-mounted antenna. Optimizing the pointing of the boresight of the antenna minimizes sidelobe generation, and thus Co-Channel Interference (CCI) in geographic areas served by the system. By minimizing CCI, the overall system performance of the communication system is optimized. To optimize the pointing of the boresight of the antenna, the overall performance of the satellite communication system is determined, and the boresight of the antenna is iteratively repointed in the direction of increasing system performance until the optimized boresight pointing is determined. Alternatively, the frequency re-use plan of the satellite communication system may be analyzed to determine a high density cell region and the boresight may be pointed to the high density cell region.

A system for estimating an antenna boresight direction. The novel system includes a first circuit for receiving a Doppler measurement and a line-of-sight direction measurement corresponding with the Doppler measurement, and a processor adapted to search for an estimated boresight direction that minimizes a Doppler error between the Doppler measurement and a calculated Doppler calculated from the estimated boresight direction and the line-of-sight direction measurement. The line-of-sight direction measurement is measured relative to the true antenna boresight, and the calculated Doppler is the Doppler calculated for a direction found by applying the line-of-sight direction measurement to the estimated boresight direction. In a preferred embodiment, the first circuit receives a Doppler measurement and a line-of-sight direction measurement from each of a plurality of pixels, and the processor searches for an estimated boresight direction that minimizes a sum of squares of Doppler errors for each of the pixels.

A system and processes for aligning an antenna boresight from a position which is internal to a structure on which the antenna is mounted is described. The system includes a laser tracking system and a plurality of targets disposed on a surface of the antenna.

An antenna reflector includes a central segment with a peripheral coupling portion and a plurality of peripheral segments, each provided with a reflector portion and a shield portion. A proximal portion of each shield portion is dimensioned to couple with the peripheral coupling portion, a reflector portion edge of each peripheral segment is dimensioned to couple with adjacent reflector portion edges and a shield portion edge of each peripheral segment is dimensioned to couple with adjacent shield portion edges. The central segment and the reflector portion of the peripheral segments together form a reflector dish. The shield portions together provide a circumferential shield extending from a periphery of the reflector dish along an antenna boresight of the reflector dish.

A method and apparatus for calibrating such a spot beam antenna by use of scanned spot beam signal characteristics measured by a plurality of ground based navigation receivers is disclosed.

The invention discloses a light spot aligning method based on a four-quadrant detector. The light spot aligning method specifically comprises the following steps of focusing an incident beam onto a photo-sensitive surface of the four-quadrant detector by a lens, and enabling the four-quadrant detector to convert a received light signal into four paths of electric signals; amplifying the obtained four paths of electric signals by an amplifying circuit, transmitting the signals to the signal processing unit, and sequentially performing A / D (analog to digital) conversion and Kalman filtering on the four paths of amplified electric signals in the signal processing unit; performing self-adaptive threshold judging on the four paths of processed electric signals, controlling the action of a cradle head according to judging results, and enabling the cradle head to drive the four-quadrant detector to act, so as to adjust the position of the incident light beam, and align the incident light spot. The light spot aligning method solves the problem of difficulty in aligning of the light spot due to simultaneous existence of light spot drifting and malalignment between light beam and antenna visual axis.

The invention discloses a fast aiming device for a waveguide antenna, which includes an aiming base, an angle indicating device and an aiming point indicating device. The aiming base is an inverted T-shaped structure, which includes a base and an installation shaft vertically connected to the base. The surface is flat, and the lower surface of the base is recessed with a card slot, which is connected with the waveguide antenna; the angle indicating device is fixed on the upper surface of the base; the aiming point indicating device includes a laser pointer and an optical sight; the laser pointer is set on the installation shaft On the upper end, the optical sight is arranged directly above the laser pointer, the laser pointer is provided with an optical axis adjustment device, and the optical sight is provided with a visual axis adjustment device. The invention can realize fast aiming of visible aiming points at different distances on the premise of ensuring the aiming accuracy of the waveguide antenna in the measurement of the microwave radiation field, and improve the convenience of aiming the waveguide antenna in the measurement of the radiation field.