Abstract: System and method for resolving phase ambiguities of various transducer arrays, including non-coplanar interferometer antennas on an aircraft skin, in order to determine the direction of arrival of a signal received by the array and emitted by a source remote from the array.

Abstract: A substrate is provided with a multiplicity of electrically conductive elements, and the elements are interconnected to form an antenna structure for desired application. Either the antenna pattern itself may be altered according to the invention, or one or more feed points may be changed, or all of the above. As such, the electrically conductive elements may be interconnected to change the directionality of the antenna pattern, the gain, the frequency response, or other operational characteristics. The electrically conductive elements may be arranged in the form of an inchoate antenna pattern or regular array. Switches at key points of the structure enable the pattern to be changed dynamically. Such switching may be carried out in real time in accordance with transmissions/reception characteristics, or in advance using simulations associated with the switched elements.

Abstract: A transmit and receiving system including a first array including at least one antenna element disposed to provide a transmit antenna. The system further includes a second array having a second different plurality of antenna elements disposed to provide a receive antenna. The first array is coupled to a switching system, which is operative to selectively form at least one transmit beam. The second array is coupled to a beam combining system, which is operative to selectively form a plurality of receive beams.

Abstract: A shared beamformer flexibly allocates beams among phased array antenna apertures of a satellite (or other type of platform). By sharing the beamformer among the apertures, if one aperture is not providing useful coverage (due to orientation, traffic volume, signal frequency, signal polarization, etc.), the beams may be reallocated to one or more other apertures that are providing useful coverage. To share the beamformer among the phased array antenna apertures, a selector network (e.g., one or more switches) is used to select which particular apertures are to send or receive signals.

Abstract: According to one embodiment of the invention, an antenna adjustment method, system and network element is provided. The system includes a mechanism for gathering information on interference in predetermined radio cells, a mechanism for arranging the gathered information radio cell-specifically for processing, a mechanism for determining a tilting factor for each predetermined radio cell, wherein the tilting factor relates to the interference the radio cell produces to other cells, and a mechanism for searching for the radio cells having the antenna tilting factors that fulfill a set criteria.

Abstract: A radio LAN master station system which provides long distance communication and suffers from small interference by another system located inside and/or outside of a service area comprises a transceiver, and a plurality of directional antennas each directed to a respective section with some angular spacing, through a power distributor which couples said transceiver with said antennas. Polarization plane of any antenna is orthogonal to polarization plane of an adjacent antenna.

Abstract: A low profile, vehicle mounted, in-motion tracking, satellite antenna includes a pair of antenna assemblies mounted in parallel on a rotatable platform. Each antenna assembly includes two subreflectors with a plastic matching element. The outputs of the two antenna assemblies are coupled with a single phase shifter. The combined outputs are retransmitted to a receiver inside the vehicle. The satellite antenna also includes a receiver for receiving channel selection data and/or for providing two-way communication with equipment inside the vehicle. The antennae, transmitter and receiver are self-powered by a storage device which is charged by a wind driven generator. A retractable radome lowers to a lower profile when the antenna is not in use.

Abstract: An angle scanning radar system having a group antenna controlled via a beam-shaping network, a coupling device that allows the group antenna to be operated for both the transmitting and receiving directions, and a device to mix radar receiving signals with radar transmitting signals to form a mixed baseband signal, and to digitally evaluate the mixed baseband signal with regard to the solid-angle information.

Abstract: Methods, apparatuses and systems directed to a wireless network interface supporting directional antenna diversity. Directional diversity, in one embodiment, makes use of antennas with higher gain and non-overlapping patterns to provide communication over a greater area and select the best antenna to receive signals transmitting wireless frames or packets. Certain embodiments optimize wireless network systems using Orthogonal Frequency Division Multiplexed (OFDM) signals where spatial diversity protection provided by spatially-separated, omni-directional antennas is not required. In other embodiments, use and selection of directional antennas allows for sectorization resulting in performance gains such as extended coverage areas, noise reduction, enhanced efficiency, and increased throughput.

Abstract: A method and apparatus for a base station including an antenna array calculates a direction of a weight vector of a transmission beam to maximize in-phase component power for a common channel signal in a transmission channel signal for transmission to a mobile station and to minimize a sum of quadrature-phase power component and interference power for other mobile stations inside and outside a cell due to a transmission channel signal for the mobile station.

Abstract: An antenna beamformer consisting of optical irises coupled to Wavelength Division Multiplexers (WDMs). The ports of the WDMs are coupled to lens ports, where each lens port corresponds to a different antenna beam. The optical irises are optical filters with selectable center frequencies and selectable passband widths. Selection of different center frequencies and passband widths enables the selection of different ports of the WDMs, which allows the selection of one or more antenna beams. The beamformer may also have controllable delay lines to provide for additional beam steering.

Abstract: The invention relates to an antenna system (1) comprising several antennae (2), which can be connected to at least two receivers (4, 4?) via a combination unit. According to the invention, a signal processing unit (5) for evaluating the output signals of the receivers (4, 4?) and a control unit (10) are provided, by means of which at least one of the antennae can be switched to transmit mode in order to conduct a self-test. These antennae (2) transmit test signals with a test frequency that is pre-set by a first receiver (4). Said test signals are fed into at least one other antenna (2) that, via the combination device (3), is connected to the second receiver (4?) whose frequency is tuned to the test frequency. In order to conduct the self-test, the receiving levels of the second receiver (4?) are recorded as actual values and compared with predetermined set values. This results in the realization of an antenna system in which a function check is conducted with the least possible amount of complexity.

Abstract: A radar system with a radar sensor (10) which comprises a transmitting module (20), a receiving module (22) and a supply network (64), wherein the transmitting module (20) comprises a first plurality of partial antennas (26, 28, 30, 32, 34) and the receiving module (22) comprises a second plurality of partial antennas (46, 48, 50), and wherein the supply network (64) operates at least one partial antenna (30) of the transmitting module (20) together with at least one partial antenna (48) of the receiving module (22) in a first operating mode, to obtain a first, low angular resolution, and wherein the supply network operates one group of partial antennas (26, 28, 30, 32, 34) of the transmitting module (20) together with a group of partial antennas (46, 48, 50) of the receiving module (22) in a second operating mode to obtain a second high angular resolution.

Abstract: An adaptive array terminal (2000) includes a reception adaptive array unit (2030) extracting a reception signal from a base station by multiplying signals from respective antennas (#AN 1–#AN 2) of an array antenna by respective reception weights, a transmission adaptive array unit (2090) applying to respective antennas of the array antenna a plurality of signals generated by multiplying by a transmission signal by transmission weights to form transmission directivity, and a transmission weight calculator (2070) calculating transmission weights added with a specified constraint in accordance with designation in a reception signal.

Abstract: Transmit/Receive (T/R) module that provides multiple simultaneous ground to satellite links with rapid pointing and acquisition. The (T/R) module incorporates independent gain and phase control. Left-hand or right-hand circular polarization can be supplied to dual feed antennas. Present invention allows each antenna to be independently polarized. Low-cost componentry is utilized throughout. On-board control of the (T/R) module is obtained using a complex programmable logic device (CPLD) and a micro controller. CPLD provided separate control of four phase shifters, attenuators, channel polarization as well as transmitter on/off control. Telemetry is provided through built-in test (BIT) routine.

Abstract: A mobile communication terminal apparatus which performs radio communication with base stations using an adaptive array antenna which obtains an antenna output by multiplying output signals from the respective antenna elements of an array antenna by weighting factors using multipliers, and adding the resultant data using an adder estimates the arrival direction of radio waves from the base station, and starts adaptive control on the adaptive array antenna, at the time of handover from the one base station to the other base station, by using as initial values the weighting factors obtained in accordance with the arrival direction estimation result obtained prior to the handover.

Abstract: An apparatus (and corresponding methodology) for discovering beacon signals in a spread spectrum radio communication system is selectively operable in one of two modes. The first mode employs a local reference timing signal, while the second mode employs a GPS-derived reference timing signal. Preferably, the first mode identifies a baseline beacon signal that satisfies a constraint based upon time delays for detected beacon signals which are indicative of the relative distance of the transmitting base stations, thus providing selection of a baseline beacon signal that originates from a relatively close base station. The index of the baseline beacon signal is recovered and then used together with relative timing derived from the local reference timing signal to assign indices to other detected beacon signals.

Abstract: An antijam module (10) for GPS utilizing the vertical and horizontal polarizations of signal output by each antenna element in an array of antenna elements. This effectively doubles the number of channels from the conventional number of channels (N) to 2N. Each of these channels is uniquely weighted in accordance with conventional teachings such that the system operates with a capability to null 2N?1 jammers. Another aspect of the invention is the provision of a system and method for moving the reference channel from one channel to another in respect to the detection of received power levels. In specific implementations, the applied weights are dithered in a predetermined direction and a predetermined amount to ascertain when and whether to pass the reference channel designation.

Abstract: An approach position input device includes a plurality of antennas arranged in the form of a lattice. An oscillator applies a high-frequency ac voltage to the antennas. A signal processing circuit processes signals from the antennas. A change-over switch including switching elements sequentially changes over a connection between the antennas and the signal processing circuit. CPU sends a selection signal to the change-over switch for antenna selection. CPU calculates an approach position of a human body according to signals from the signal processing circuit. CPU instructs the change-over switch to apply the ac voltage from the oscillator only to the antenna selected according to the selection signal.

Abstract: System and method for signal processing and beam forming. A system for processing signals includes a first phase shifter, a second phase shifter, a first variable time delay system, and a second variable time delay system. Additionally, the system includes a first signal processing system and a sampling system. Moreover, the system includes a switching system and a measuring system.

Abstract: Method and device for the detection of one or more mobiles within a communications network, the method comprising at least one step for the “acquisition” of at least one RACH type signal exchanged between a mobile and a base station of the network and a step to measure the angle of arrival of the signal, the measurement step being synchronized with a parameter of the exchanged signal. Application to the GSM network.

Abstract: A transverse device array phase shifter includes an overmoded waveguide structure having a top conductive broad wall surface, a bottom conductive broad wall surface and opposed first and second conductive side wall surfaces. At least one transverse device array circuit is positioned in the waveguide circuit. Each circuit comprises a generally planar dielectric substrate having a microwave circuit defined thereon, and a plurality of spaced discrete phase shifter elements. The substrate is disposed within the waveguide structure generally transverse to the side wall surfaces. A bias circuit applies a voltage to reverse bias the phase shifter elements. The transverse device array phase shifter circuit causes a change in phase of microwave or millimeter-wave energy propagating through the waveguide structure.

Abstract: A wireless communication method and antenna system for determining the direction of arrival (DOA) of received signals in azimuth and elevation, (i.e., in three dimensions), to form a beam for transmitting and receiving signals. The system includes two antenna arrays, each having a plurality of antenna elements, two first stage multi-mode-port matrices, at least one second stage multi-mode-port matrix, an azimuth phase detector, an elevation amplitude detector, a plurality of phase shifters and a transceiver. The antenna arrays and the first stage multi-mode-port matrices form a plurality of orthogonal omni-directional modes. Each of the modes has a characteristic phase set. Two of the modes' phases are used to determine DOA in azimuth. The second stage multi-mode-port matrix forms a sum-mode and a difference-mode used to determine the DOA of the received signals in elevation. A beam is formed in the direction of the received signals by adjusting the phase shifters.

Abstract: Wireless communication and beamforming is improved by depopulating one or more ports of a passive beamformer such as a Butler matrix and/or by increasing the order thereof. In an exemplary implementation, an access station includes: a Butler matrix having “M” antenna ports and “N” transmit and/or receive (TRX) ports; wherein at least a portion of the “M” antenna ports and/or at least a portion of the “N” TRX ports are depopulated. In another exemplary implementation, an access station includes: a Butler matrix that has multiple antenna ports and multiple TRX ports; a signal processor; and a signal selection device that is capable of coupling the signal processor to a subset of the multiple TRX ports responsive to a signal quality determination, the signal selection device adapted to switch the signal processor from a first TRX port to a second TRX port of the subset of TRX ports.

Abstract: A signal processing unit carries out signal processings necessary for a receiving/transmission processing of an adaptive array antenna. The signal processing unit also carries out a signal processing necessary for determining phase errors in quadrature modulation and quadrature detection to be done by radio units, namely, for determining a rotation amount of an initial phase correction value. The radio units in a base station apparatus carry out frequency conversion processing, amplification processing, quadrature modulation processing, quadarture detection processing, A-D or D-A conversion processing and the like between the baseband signals and radio frequency signals. An initial phase correction value determining unit determines rotation amounts of initial phase correction values, based on power-measuring received signals inputted from the radio units, and outputs to the signal processing unit as initial phase correction value signals.

Abstract: A process for locating radio sources by a two-channel high resolution radiogoniometer including a network of a specified number N of sensors. The process multiplexes the signals supplied by the N sensors on the inputs of only two receivers. Then, with the aid of a calculation device coupled to the outputs of the two receivers, the angles of arrival of the waves emitted by the sources are estimated on the basis of an estimation of the covariance matrix of the signals supplied by the two receivers.

Abstract: A reconfigurable wide band phased array antenna for generating multiple antenna beams for multiple transmit and receive functions. The antenna array comprises multiple long non-resonant TEM slot antenna apertures with RF MEMS switches disposed within the slots. The RF MEMS switches are positioned directly within the feed lines across the slots to directly control the coupling of RF energy to the slots. Multiple RF MEMS switches are used within each slot, which allows multiple transmit/receive functions and/or multiple frequencies to be supported by each slot. The frequency coverage provided by the slot antenna has a greater than 10:1 frequency range.

Abstract: A dynamically variable beamwidth and/or variable azimuth scanning antenna includes a plurality of active radiating columns and a plurality of continuously adjustable mechanical phase shifters. The columns define a beam having a beamwidth and an azimuth scan angle. Each phase shifter has an independent remotely controlled drive and is directly electrically connected to a respective radiating column. The phase shifters are independently operated to vary the beamwidth and/or azimuth scan angle of the beam defined by the plurality of active radiating columns.

Abstract: In order in simple manner to switchably cover a wide angle in sectors using an antenna array with broad main lobe, an antenna elements are so arranged, that the elements can be individually selected, so that some elements of the array can be operated in-phase and other elements operated in phase-opposition relative to each other. In order to determine the entry direction of a received signal, it is possible to operate the antenna array with non-symmetric antenna diagram, or however also to additively influence the symmetry of antenna characteristic by the use of a supplemental receiver element.

Abstract: A self-structuring antenna (SSA) system employs a memory device to store switch states for antenna configurations that are determined to produce acceptable antenna characteristics. Each antenna configuration corresponds to a respective combination of switch states known as a switch configuration. Using the stored antenna configurations as a starting point for the process of searching for an antenna configuration that produces acceptable antenna characteristics under particular operating conditions may reduce the search time.

Abstract: A receiver for improving reception ability of digital broadcasting service by switched beam-forming is disclosed. The receiver includes: an array antenna having a plurality of antenna elements for receiving signals of the digital broadcasting service; a demodulation unit for demodulating the receiving signals corresponding to each of antenna elements in the array antenna; beam-forming unit for generating a predetermined number of beam-forming signal by applying a beam-forming weights in order to direct to a predetermined direction according to the modulated signal from the modulation unit; and beam selection unit for selectively receiving signals of desired direction according to the beam forming signal. The present invention effectively eliminates multipath based on space filtering by utilizing beam-forming method with an array antenna for improving receiving performance of digital television broadcasting with VSB.

Abstract: Disclosed are an adaptive beamforming apparatus and method that despreads an input signal, and determines whether a symbol of despread signal belongs to a pilot sub-channel or non-pilot sub-channel of the despread signal. One of two beamforming algorithms is accordingly enabled. If the symbol belongs to the pilot sub-channel, a first algorithm is used to calculate a weight vector, and if the symbol belongs to the non-pilot sub-channel, a second algorithm is used to calculate the weight vector. A current weight vector is updated using newly calculated weight vector, and a beam pattern is formed based on the updated weight vector.

Abstract: An array antenna system comprising an array of antenna elements and a receiver which uses a subset of the signals from the antenna elements, the selection of the subset of signals which should be used for a particular user is made on the basis of measurements of potential performance of the receiver with each subset of signals, combined, rather than of each individual signal.

Abstract: A method for scanning of antenna array, wherein on output signals from radiating elements are applied phases offset in order to obtain signals with approximately equal phases. The obtained signals are subsequently summated. The method is characterized in that before application of phase control the output signals from radiating elements are grouped by means of summation of the signals with approximately equal phases in order to form equivalent group signal. Subsequently the phase offset is applied on all group signals and subsequently all group signals are summated.

Abstract: Disclosed is a method and apparatus for multipath mitigation using an antenna array. An antenna array made up of a plurality of antennas is used to receive satellite signals from satellites. Various configurations of antenna arrays is disclosed, including a linear vertical antenna array and a horizontal antenna array in which the antenna elements are located in a horizontal plane. A switch sequentially connects each of the antenna outputs to a single processing path to generate a common additive signal. The common additive signal is provided to satellite channel processors, each of which processes the signals from an associated satellite. A phase shift correction signal associated with each of the antennas is generated and synchronously applied to a carrier phase reference signal. A blocking signal may be applied to the satellite channel processors in order to block the processing of signals from an unwanted satellite.

Abstract: Disclosed is a radar apparatus which receives a transmitted signal reflected from an object by switching between a plurality of antennas, wherein the plurality of antennas are divided into a plurality of groups, and at least one of the plurality of antennas contained in each of the groups is a common antenna.

Abstract: A phase shift control voltage distribution scheme for a phased array utilizing voltage-proportional phase shift devices employs a digital-to-analog converter that supplies respectively different analog voltages to a sample-and-hold switch network coupled to analog voltage control inputs of the plurality of voltage-proportional phase shift devices. In order to impart a phase shift control voltage to one or more phase shift elements of the array, a control unit supplies a prescribed combination of a digital control code to the digital-to-analog converter and a switch control code to sample-and-hold switches of the switch network.

Abstract: The beam pattern associated with a multi-beam antenna array is adjusted if a first beam of the beam pattern is overloaded. A lobe of a second beam of the beam pattern can be steered away from a main lobe of the first beam. Also, if a user is located in an area covered by a second beam which is adjacent to the first beam, a third beam of the beam pattern can be selected for effectuating communication with the user. If a user is located in an area covered by the first beam, another beam of the beam pattern can be selected for effectuating communication with the user.

Abstract: A circuit for the selective activation of a plurality of antennas (L1 to L4) from a common end stage (8) contains a first selector switch (10) at a terminal (6) of the end stage (8), the switch contacts (12, 22) of which are each connected to a switch contact (20, 26) and via an antenna (L1, L2) each to one fixed contact each of a twin selector switch (14, 24). The fixed contacts of the twin selector switch are each connected via a further antenna (L3, L4) to the other terminal (18) of the end stage and these are also connected to the other switch contacts (16, 28) of the twin selector switch.

Abstract: The invention relates to a system and method for processing a signal being emitted from a target signal source 20 into a noisy environment, wherein said target signal source 20 is located in a target signal source direction &phgr;s with regard to the position of a transducer array 10, the method comprising the following steps: receiving, transforming and filtering said signal according to filter coefficients of a beamformer 30I, 30II in order to generate at least one beamformer output signal y′i(n), i=1 . . . N, the filter coefficients defining a desired predetermined filter characteristic of the beamformer; and generating a control signal t(n) representing said target signal source direction &phgr;s. It is the object of the invention to improve such a system and method in the way that clear signal reception is achieved for any target signal source direction &phgr;s with only a minimum of computational effort and memory capacity.

Abstract: Disclosed is a control apparatus capable of more effectively utilizing radio resources. Mobile stations positioned close to each other are treated as one group, and a direction and width (radiation angle) of a beam radiated from an adaptive array antenna 11 is controlled for each group so that one beam capture one group. To be concrete, a plurality of mobile stations are classified into groups by a classification section 19, and an area to which each group moves is estimated by a directivity determination section 20. The adaptive array antenna 11 is controlled by the directivity control section 15 so that one beam can cover an area in which one group is positioned and the area to which this one group moves.

Abstract: Antennas having a circular array of radiating elements are arranged to enable continuous 360 degree scanning of a sum and difference beam pattern. With a 108 element circular array, a sub array of 27 contiguous elements may be step scanned to 108 positions while maintaining sum and difference antenna patterns. Each scan step may require only two switch adjustments, one to initiate excitation of a contiguous leading element and terminate excitation of the trailing element, and the other to change coupling of a middle element from a divided power port of a left power divider to such a port of a right power divider. Configurations using sub arrays whose element complement is not evenly divisible into the total number of array elements, using sub arrays consisting of an odd number of radiating elements, or employing minimized feed network complexity are disclosed.

Abstract: A satellite antenna system (30) that employs a small phased antenna array (46) acting as redundant antenna. Because the phased array (46) is steerable, it can be selectively directed to any of the cells (16) on the Earth (12) in the event that the LNA in an antenna channel (32) fails. The phased array (46) is switched into each antenna channel (32) after the channel front end (40) where a switch (56) used to switch in the phased array (46) is after the amplification in the channel (32). Therefore, the switch (56) does not significantly affect the noise figure of the channel front end (32).

Abstract: A dynamically reconfigurable antenna system is disclosed which may be configured with low cost discrete analog components. Particularly, the antenna elements, phase shifters, and beam forming network of the current smart antenna system are configured from RF transmission lines, RF couplers and RF switches in a system which is able to dynamically reconfigure its beam forming signals to point in a direction of greatest signal strength. The smart antenna system may be configured on portable devices to accomplish greater signal reception and transmission when used in a wireless network.

Abstract: An antenna array comprising at least two groups of antennas where each group comprises at least two pairs of antennas. Each of the pairs in a group contains orthogonally polarized antennas and at least one antenna in a pair is similarly polarized to one antenna in at least another pair in the group. The antenna array further comprises circuitry coupled to the antenna groups to select and activate certain antennas in a group to enable the antenna array to operate in either a beam forming/steering mode, a diversity mode or a MIMO mode or any combination thereof. The antennas in the groups are activated based on the characteristics of the signals being transmitted or received by the antenna array.

Abstract: A main control unit in a radio reception apparatus selects from an adaptive array reception mode and a single route reception mode, in accordance with a prescribed condition. When the adaptive array reception mode is selected, the main control unit performs first control to operate a plurality of radio reception units and an adaptive array operational processing unit. When the single route reception mode is selected, the main control unit performs second control, so that one radio reception unit is selected as a first radio reception unit to operate and an operation of a radio reception unit other than the first radio reception unit and the adaptive array operational processing unit is stopped.

Abstract: The present invention relates to a beamforming method for smart antenna arrays, and in particular relates to a beamforming method for smart two-dimensional antennas. Smart antennas employ arrays of low gain antennas connected to a combining/beamforming network. Smart antennas can provide enhanced coverage through range extension, hole filling and improved building penetration. By improving transmission and reception at the base station, the tolerable path losses can be increased whereby the range of the base station can be improved. A first aspect of the invention thus provides a method of generating low sidelobe beampatterns for 2-dimensional arrays. A further aspect addresses the feedback signalling techniques which are presently being considered by standard bodies for four antennas in large arrays. The invention is suitable for CDMA wireless cellular systems, as presently determined for third generation cellular wireless networks, and other wireless systems such as TDMA systems and wireless LANs.

Abstract: A configurable directional antenna includes a center antenna element, a plurality of second antenna elements, and a switch matrix. Each second antenna element, together with the center antenna element, defines an antenna sector. A first portion of the second antenna elements is disposed at an inner radius around the center antenna element. A second portion of the second antenna elements is disposed at an outer radius around the first portion antenna elements. Each antenna sector comprises one of the radially inner antenna elements, one of the radially outer antenna elements, and a conductor extending between the one radially inner and the one radially outer antenna element. The switch matrix comprises first electronic switches for selectively grounding selected ones of the second antenna elements, and second electronic switches each for selectively connecting together the second antenna elements of one of the antenna sectors with the associated conductor.

Abstract: An approach to antenna design optimizes gain, beam pattern, polarization response, and other qualities through self-replicating patterns based upon iterative transformations and candidate geometric shapes. In the preferred embodiment Hausdorff structures are used to realize &lgr;n-arbitrary different radiation patterns, including patterns optimized for multiple frequencies. The most preferred approach applies a sequence of different Hutchinson operators to different geometric subsets, thereby achieving patterns which are not only arbitrary in terms of wavelength/frequency, but also permit variable radiation patterns and variable polarization other desirable criteria. In addition to the use of variable scaling, geometric patterns, and the like, multiple structures may be placed within the same spatial footprint to permit reception over more bands.

Abstract: The present invention provides an antenna system including a body for use in determining N unknown parameters values relating to an object located in the vicinity of the system. The system further includes an antenna array comprised of a plurality of elements that are spaced to reduce ambiguities in the subsequently determined N values. In one embodiment, several pair of elements are used. The spacing between the elements comprise the pairs and the spacing between pairs reduces ambiguities. The antenna system also includes a beamformer for producing a plurality of beams and a device for using the plurality of beams to determine N values associated with the object. The amplitude of the plurality of beams can be compared to obtain coarse data on the object.