Abstract: An adaptive antenna reception apparatus includes a reference signal level determination section, reception level detection sections, and beam formers. The reference signal level determination section determines the level of a reference signal for generating an error signal used for antenna adaptive control on the basis of a reception level of each antenna before beam forming. The reception level detection sections calculate antenna weighting factors for the respective paths on the basis of the multiplex signals received through the respective antennas and the error signal output from the reference signal level determination section. The beam formers receive the received multiplex signals and form antenna directivity beams for the respective paths in accordance with the antenna weighting factors output from the reception level detection sections.

Abstract: A method for accurately tracking and communicating with a satellite from a mobile platform, wherein the satellite has an antenna which performs both transmit and receive functions from a single antenna aperture. The method involves using an inertial reference unit (IRU) of the mobile platform to initially acquire the signal from the satellite. A sequential lobing process is then used to more accurately center the antenna aperture relative to the receive beam from the satellite. The antenna is then used to transmit data or other information, and the antenna pointing is maintained by an additional IRU local to the antenna with higher accuracy and lower latency than the IRU of the mobile platform. Periodically, transmissions from the antenna are inhibited and the sequential lobing process is repeated to eliminate for any inertial reference drift error.

Abstract: A method and apparatus for predicting uplink and/or downlink beamforming in a wireless communication system employing an antenna array. The method and apparatus may predict uplink and/or downlink weights as a function of previous uplink and/or downlink weights. An interpolation of a sample of uplink weights and/or downlink weights is used to predict a future uplink or downlink weight.

Abstract: A system for directing a receiving lobe of an adaptive antenna array toward an aircraft in flight includes an aircraft position vector calculator and an antenna weight vector generator. The aircraft position vector calculator receives aircraft position information from an aircraft tracking service and calculates, based upon the aircraft position information it receives, an aircraft position vector g. An antenna weight vector generator receives the aircraft position vector g from the aircraft position vector calculator and generates, based upon the aircraft position vector g, an antenna element weight vector w. The antenna weight vector w is applied to the elements of an adaptive antenna array to direct a receiving lobe of the array towards an aircraft in flight.

Abstract: In a communication device that includes an antenna array including multiple antennas, a method and apparatus is provided for determining whether to employ an antenna array beamforming technique. The communication device determines a bearing from the communication device to the communication unit and a direction of arrival for a signal received from the communication unit by the communication device via each of the multiple antennas. In addition, the communication device determines a distance from the communication device to the communication unit, and also determines multiple signal quality metrics based on multiple signals received by the communication device from the communication unit. The communication device then determines whether to employ an antenna array beamforming technique based on any one or more of the determined bearing and the determined direction of arrival, the determined distance, or the determined signal quality metrics.

Abstract: A system and method for establishing a beam forming phase reference line remote from an antenna system is taught. By providing a phase reference line at a selected position in the signal path the present invention allows for a beam forming matrix to be utilized in providing distributed amplification without requiring additional power sharing matrix arrangements. Moreover, disposing of the phase reference line at a selected point in the signal path according to the present invention allows for multi-mode communications wherein both switched beam and adaptive beam forming may be utilized.

Abstract: An arrangement for controlling radar transmissions for a system of antennas disposed on a moving platform. The radar transmissions are allocated to an antenna face for a future transmission. To effect an adequate allocation, a prediction arrangement is provided to predict the angular position of the moving platform and the antenna faces. Preferably an antenna is assigned that realizes the smallest off-broadside angle of the radar transmission.

Abstract: A phased array antenna phase shifter having one or more serially connected stages, the stages allowing a transmission signal to pass through to a radiating element. Each of the stages have three or more delay lines for imparting a different respective delay on the transmission signal and a network of switches to select which of the delay lines within the stage will carry the transmission signal. As the signal is passed through each of the stages, the signal will experience the cumulative delays from the stages of the phase shifter. The delay lines in each stage comprise delay lines of different respective lengths, a delay is imparted on the transmission signal as it passed along the length of the selected delay line. The network of switches comprises micro electromechanical systems (MEMS) switches.

Abstract: A system for directing a receiving lobe of an adaptive antenna array toward an aircraft in flight includes an aircraft position vector calculator and an antenna weight vector generator. The aircraft position vector calculator receives aircraft position information from an aircraft tracking service and calculates, based upon the aircraft position information it receives, an aircraft position vector g. An antenna weight vector generator receives the aircraft position vector g from the aircraft position vector calculator and generates, based upon the aircraft position vector g, an antenna element weight vector w. The antenna weight vector w is applied to the elements of an adaptive antenna array to direct a receiving lobe of the array towards an aircraft in flight.

Abstract: Signal processors that support transmit or receive beams of two dimensional array antennas generate an appropriate distribution of phase shifts and/or time delays for each of the elements in the antenna array. The signals are processed by row and by column, where corresponding elements are grouped using intermediate frequency tagging, i.e., the elements of a first column are translated to a first intermediate frequency, the elements of a second column are translated to a second intermediate frequency, etc. Signals from elements of like rows are then summed and subjected to a row delay. The delayed signals are then summed and passed through a filter bank, where the summed signal is partitioned in accordance with the plurality of intermediate frequencies into a plurality of column signals. The column signals are subjected to a respective column delays, are translated to a common intermediate or baseband frequency and are summed to establish a received beam signal.

Abstract: An array antenna receiving device which compensates a phase deviation to perform an efficient beam forming while keeping phase difference information between receivers determined by the arrival direction of a user signal in a communication area to which an antenna element is directive and the array of antenna elements in a radio base station. An analog beam former provides a composite beam so that a phase difference between adjacent beams may have a fixed value determined by beams to be selected. A phase compensator provides digital signals of receivers with phase correction quantities based on any one of the digital signals so that phase differences between the antenna elements may have a fixed value.

Abstract: A planar array antenna for use with an earth-based subscriber unit generates receive or transmit communications beams through the use of digital beamforming networks (210, 211) which provide beam steering in a first dimension. In another dimension, the communications beams are synthesized by way of a waveguide structure (300, FIG. 3) which is repeated for each row of the antenna array. The waveguide outputs are weighted due to the positioning of coupling slots (350) or coupling probes (450) which transfer carrier signals to and from each waveguide. The slots or coupling probes from the waveguides are coupled to a group of barium strontium titanate (BST) (360, FIG. 3) or micro-electromechanical systems (MEMS) switch (460, FIG. 4) phase shift elements which are under the control of a control network (221, 222, FIG. 2). The resulting signals are radiated by the antenna elements of the planar antenna array (310, FIG. 3) to form a communications beam.

Abstract: An algorithmic technique which allows antenna arrays that are used for interferometric direction finding to have elements with arbitrary orientation. This technique allows the phase errors associated with non-identical element orientation to be estimated, without explicit knowledge of either the polarimetrics of the array elements or the polarimetrics of the source. It relies upon the fact that there exists a single number which describes the polarimetric interaction, and that this number can be estimated and then utilized to remove the phase component due to polarimetric interaction. This technique makes it feasible to incorporate direction finding arrays into articles that could benefit from such arrays, but because of size or shape constraints, were previously not able to do so.

Abstract: A direction of arrival (DOA)-aided digital beamforming (DBF) subsystem (300 FIG. 3) is provided for mitigating interference and increasing the frequency reuse factor in communication systems. The DOA-aided DBF subsystem is used to accurately position beams and nulls in at least one antenna beam pattern. By accurately directing beams at desired locations and nulls at undesired locations, the DOA-aided DBF subsystem provides a more efficient processing of antenna beam patterns in communication systems. The DOA-aided DBF subsystem is used in geostationary satellites, non-geostationary satellites, and terrestrial communication devices. The DOA-aided DBF subsystem uses a unique algorithm to determine DOA information that allows more efficient beam management and allows more subscribers to be served, while saving spectrum and power.

Abstract: A "just in time" pipelined signal processing architecture for a phased array antenna simultaneously updates the weights of all phase control elements of the antenna with reduced wiring complexity and fast beam steering updates. Signal propagation paths between a pipelined communication link--through subarray control processors distributed along the pipeline link--and phase control elements of the antenna array are provided with respectively different serial pipelined transport delays. These delays are such that all phase control signals produced by the subarray control processors are applied simultaneously to their associated subsets of antenna phase control elements. The use of serial (FIFO) delays to equalize pipeline and weight processing latency allows each subarray controller to process and forward serial beam vector data at the same data rate at which it is received from an upstream host processor.

Abstract: An optical antenna pointing controller for an optical antenna system having an optical antenna and biaxial gimbal mechanism coupled to the optical antenna and mounted on the satellite is provided. Feedback control in the controller is gain-stabilized by a nominal compensator, and disturbance is suppressed by a robust compensator, further, a target satellite is captured quickly with the aid of a reference model and feedforward, thus providing quick response without dependency on the band width of feedback control system.

Abstract: Apparatus for calibrating a phased array antenna having a plurality of active modules and a test manifold. An RF antenna, which is both a transmitting and receiving antenna is positioned at a far field range from the antenna to be calibrated. A receiver is connected to the output of the far field receiving antenna and the output of the test manifold of the antenna to be calibrated for the transmit calibration and a transmitter is connected to the far field transmitting antenna and the test manifold for a receive calibration, a command phase and amplitude for each steering angle of each module of the antenna being calibrated. The phase and amplitude data from the test manifold is compared with the phase and amplitude data of the far field range to obtain an error signal, and the error signal is combined with the command amplitude and phase iteratively until the error signal is minimized for each module of the antenna.

Abstract: An apparatus and method for calibrating a plurality of sensors having a predetermined spatial distribution.

Abstract: Disclosed is a method for the management of the beam of an electronically scanned rotating antenna. For each antenna rotation, the sequencing of the commands is organized in three phases associated with zones of the space: a first phase of preparation of the requested aiming operations before their entry into the visibility cone of the antenna; a second phase of carrying out the requested aiming operations present in the visibility cone; a third phase of identifying the requested aiming operations that have come out from the visibility cone and have not been carried out. Application to multi-function radars.

Abstract: An antenna array (10) includes a plurality of antenna elements (12), each of which is associated with a transmit-receive TR module (14). The antenna elements and their associated TR modules are grouped into sets, which in the illustrated embodiment are sets of four. Each set of four TR module/antenna elements is associated with one phase and gain controller (18.sub.X), which is part of a distributed phase and gain controller. The beam direction is commanded by a central radar control computer (RCC) (22), which transmits beam direction and other information to all the separate phase/gain controllers. Each separate phase/gain controller accesses local memory to obtain data relating to the location within the array of those antenna elements which it controls. Each phase/gain controller then calculates the necessary phase shift for each antenna element it controls, taking into account the phase and gain errors associated with the TR module associated therewith.

Abstract: An antenna system for transmitting radio waves in the same direction as the direction of arrival of incoming radio waves. The arrival direction is detected by a fast Fourier transform processor. The transmitting direction is adjusted by phase-shifting radio waves from a feeder on the basis of the detected arrival direction. Further, signals in the system are transmitted through optical fibers in order to decrease the processing time.

Abstract: Disclosed is a method and apparatus for calibrating phased array receiving antennas that includes circuitry for generating a pair of calibration signals separable one from the other. The signals are injected into the delay elements of the antenna from opposite ends of a complementary calibration cable. The delay produced in the calibration signals is individually measured, and the delays summed and averaged to produce a delay measurement independent of delays produced by the calibration cable and accordingly delay measurement variations caused by environmental effects on the calibration cable.

Abstract: A phased array system comprising a plurality of elements each element being arranged to transmit/receive signals with a predetermined phase and/or amplitude with respect to other elements of the array, whereby a beam steering function is afforded, each element of the array including a transducer, the trnasducers of the array elements being placed in communication with at least three reference stations which are spaced apart in three dimensions such that data communication between each transducer and the reference stations can be used to define the position of each element relative to the stations and wherein the phase and/or amplitude of signals transmitted and/or received by the elements is determined in dependence upon the said relative position thus defined, whereby improved beam steering accuracy is afforded.

Abstract: A system and method for controlling the times of activation and deactivation of transmit amplifiers, receiver amplifiers and receiver protectors of multiple T/R modules during successive transmit and receive cycles of an active aperture phase array antenna of a radar system. The corresponding elements of each T/R module are delayed to operate like elements simultaneously. The delayed application of this T/R signal to the like element is varied for operating unlike elements of the array at predetermined times relative to one another. A system and method for determining the required delay is disclosed.

Abstract: In a system having plural signal-carrying channels, a phase shift is introduced between a signal in one of the channels and a reference signal for calibrating the individual channels. The reference signal is obtained by adding samples of signals in other ones of the channels. The phase shift is introduced by phase-shift apparatus responsive to a command signal directing a continuous monotonic increment of phase. The phase incrementing introduces a frequency shift (a serrodyne), which produces a beat-frequency signal for mixing a channel signal with the reference signal. The beat-frequency signal is phase locked to a modulation patern of a command signal, whereby a measurement of phase (or delay) can be made between the two signals for calibration of each channel within the system.

Abstract: An improved means of decorrelating phase quantization errors in a phased array radar antenna using digital randomization at each of the array elements to reduce peak steering erorrs and to reduce peak sidelobe levels of the antenna. A random phase adjust term is provided to each of the array's antenna elements which comprises a distributed controller (DC) co-located with a digital phase shifter. The distributed controllers are each programmed with a random phase adjust term which represents a phase shift adjustment statistically independent from element to element. The random phase adjust term is stored in a memory located in each disbtributed controller. The distributed controller drives each element's digitally controlled phase shifter in response to a beam steering command received over a serial line. The performance improvement achieved with this decorrelation method is equivalent to that obtained by using more expensive phase shifters and adding costly randomized cables in the path to each element.

Abstract: This antenna system has a plurality of elementary antennas configured into an array, wherein there is a reception (or transmission) channel associated with each antenna or sub-array of antennas, said reception channel having, in series:an active reception module,delay means capable of selectively introducing a pure delay of propagation of the signal picked up by the elementary antenna so as to produce a gradation of delays for the different respective elementary antennas, said gradation of delays enabling the definition of a desired pointing in the direction of the wave to be received with respect to the orientation proper to the array;and an analog/digital converter receiving, at input, the analog signal received, to deliver, at output, a corresponding digitized signal to a beam forming computer.

Abstract: An antenna control data transfer system having antenna elements, phase shifters changing the phase of electromagnetic waves transmitted or received by the antenna elements, and phase shifter control circuits controlling the phase shifters, wherein each of the phase shifter control circuits includes an address holding circuit storing an address for identifying the phase shifter control circuit, a data input circuit for receiving data, and a data output control circuit for selectively outputting the received data or inhibiting the data output in accordance with a control signal from a signal processor.

Abstract: A beam steering module for rapidly applying control signals to a plurality of digital phase shifters in a phased array antenna system. The module can receive and store a plurality of phase shift commands for a plurality of phase shifters. The commands may be quickly applied to the phase shifters to rapidly steer the beam from the antenna array.

Abstract: The method and system for reducing phase error of phased array radar beam steering controllers having digitally controlled phase shifters includes the monitoring of individual digitally controlled phase shifter elements, determining an additive phase correction to reduce the number of failed phase shifter elements, determining whether said additive phase correction is achievable by comparing the stuck bit state at each said failed changers element with said additive phase correction and adjusting the phase commands to the nearest values which can be achieved if the additive phase correction is unachievable.

Abstract: A conformal array antenna system is disclosed comprising a structural base body having a shape suitable for a surface of an airplane or a ship, and a plurality of antenna units disposed on the structural base body. Signals received by these antenna units are converted into digital signals and fed to a digital beam forming circuit which synthesizes such digital signals to form a multiplicity of beams. The antenna units and the digital beam forming circuits may be connected by electrical transmission lines or optical fibers.

Abstract: An active array system is disclosed with electronic roll stabilization of the difference patterns, and with arbitrary partitioning of the phase scanned aperture with no hardware changes. The array system comprises a large number of radiating elements forming the array, with individual transmit/receive active modules coupled to each radiating element. In each active module, the received signal is amplified and then divided into three signal components. Two of the signal components are passed through a bi-state phase shifter for selectively phase shifting the signal component by 0 to 180 degrees. The selectively phase shifted receive signals are then coupled to the respective azimuth and elevation difference channels. The third signal component is coupled to the sum channel network. The respective sum and difference channels all provide summing functions on the respective sum and difference signals from each module.

Abstract: In, for example, a passive direction-finding radio receiver employing a multi-beam antenna which has e.g. ninety-six feeds which form a corresponding number of overlapping reception beams, the output signal amplitudes of the various feeds can be compared with a reference to yield a sequence of binary digits, e.g. as shown in FIG. 2. The position of a radio source is given by the position in the sequence of the center of the largest group of "1"s. In order to quickly determine this position the sequence is subjected repeatedly to a processing operation in which each "1" which does not have "1"s as its two immediate neighbors is changed to a "0", thereby repeatedly stripping the two end "1"s off each group of "1"s until none remain. The required position is that of the single "1" or pair of "1"s present immediately before all have become "0"s.

Abstract: An RF signal receiving/transmitting apparatus for use with a phased array antenna having a plurality of antenna elements comprises a plurality of signal processing circuits, each circuit being connected to and associated with one of the antenna elements and including a signal distributing/combining device connected to its associated element, a plurality of sampling gates for spatially sampling a distributed signal or applying analog samples to the distributing/combining device, and analog-to-digital or digital-to-analog converters connected to an analyzer for analyzing/generating a plurality of digital samples which are received or to be transmitted by the antenna elements.

Abstract: Conventionally, if several tasks have to be carried out simultaneously by receivers and transmitters, then a number of them are required, each having its own antenna.By employing the invention a single receiver or transmitter having one antenna can carry out a number of simultaneous tasks.A receiver has an array of antenna elements which receives signals and transmits them along conductors. Junctions include variable control means to apply a variable proportion of the signals on a conductor to one of a series of channels, each junction also giving a particular variable phase shift. By correctly selecting the amplitude and phase shift the outputs on the channels correspond to signals from respective directions of sensitivity of the receiver, and may be considered to represent a number of beams.

Abstract: Proper operation of a beam steering unit for a phase array antenna, is verified by simulating the pattern of wave energy which would be radiated to an observation point in space when the beam steering unit is connected to phase shifters associated with elements of the antenna. The simulated pattern thus obtained may be compared with a preset pattern for the observation point during a scanning operation of the beam steering unit, and an alarm or other indication is obtained when the difference between the simulated and the preset pattern exceeds a certain limit. The simulated pattern is obtained by storing phase angle data from the beam steering unit in a memory at areas corresponding to phase shifters associated with elements of the phased array antenna.Observation angle data corresponding to the angle of the point in space relative to the antenna array is generated, the observation angle data being a function of observation angle, antenna element spacing and radiation wavelength.

Abstract: This invention relates to apparatus and a method of controlling the amount of delay or phase-shift which is applied to a signal received at or transmitted from each transducer in a multi-transducer antenna to produce a beam directed at a specific target point. For each transducer a first look-up table is used for storing first digital words representative of the included angle between the lines joining the target to a reference point, and the same reference point to a transducer. A second look-up table is associated with the first look-up table for each transducer, and stores second digital words representing delay or phase-shift control signals corresponding to ranges of the target relative to the reference point for each of said first digital words. Each first look-up table is addressed with an address signal representing the direction of the line from the reference point to the target, to obtain a corresponding first digital word.

Abstract: Steerable phased array antennas of the tapered type in which the antenna ment power is maximum at the center of the array and tapers off on either side thereof. The phase shifters of each antenna element are of the binary digital type with the number of stages and hence the phase accuracy being maximum for the high power center antenna elements and tapering off on either side thereof. Redundant stages for the binary phase shifters can be provided to increase reliability.