Abstract: Estimating an antenna pointing error includes receiving a signal sent from a reference located within a region. A polarization ratio is evaluated over the region. A minimum polarization ratio variance for the polarization ratio is established. A location corresponding to the minimum polarization ratio variance is identified. An antenna pointing error is estimated from the identified location.

Abstract: A digital polarimeteric system employs a signal time stretching technique and digital signal processing of the time-stretched signal to accurately measure the polarization of a received RF signal with commercially available digital hardware. A superheterodyne receiver down converts received RF signal components to IF, and analog-to-digital converters sample the signal components at much lower sampling rates than would normally be required to accurately measure the signal polarization. Each signal sample is “time stretched” by storing each sample in M locations in a memory, such that N samples occupy M×N memory locations. A digital signal processor applies incremental phase shifts to the digital samples until a phase-shifted combination of the digital samples yields a minimum null output. The phase shifts producing the minimum null identify the polarization of the received signal.

Abstract: A base station for a wireless communication system is capable of transmitting signals that match the polarization state of a mobile station by including an antenna arrangement having at least one set of transmit antenna elements and at least one set of receive antenna elements, a transformation mechanism having at least one antenna port coupled to the antenna arrangement and at least one beam port, and an adaptive measurement and control mechanism coupled to the transmit and receive antenna port signals and configured to measure and adaptively control attributes of the transmit and receive antenna port signals.

Abstract: Previous MIMO systems have used spatially diverse antenna elements in order not to reduce the number of orthogonal channels that can be realized. The present invention recognizes that this leads to large antenna sizes, as compared to multiple beam antenna systems which use closely spaced antenna elements. In order to provide a compact antenna unit, while still allowing a MIMO system to be exploited, the present invention recognizes that polarization diversity only can be used in a MIMO system without the need for spatially diverse antenna elements. Closely spaced antenna elements are used and this enables a compact MIMO antenna unit to be provided. In addition, such MIMO systems with polarization diversity but no spatial diversity can advantageously be used in line of sight situations and also combined with multi-beam antenna systems to further increase capacity.

Abstract: Methods and apparatus for detecting objects. In one embodiment, a person entering a secured or “Safe Zone™” is illuminated with low-power polarized radio waves. Differently polarized waves which are reflected back from the person are collected and measured. In a preferred embodiment, concealed weapons are detected by calculating the difference of a pair of differences (Delta A and B) of different polarized reflected energy (upper and lower curves in the two graphs) in the time domain, and by using signal processing methods and apparatus to improve the reliability of the detection process.

Abstract: The composition of an object within a wireless communication channel is determined by analyzing a symmetry characteristic of a polarization pattern of a received signal. The signal is transmitted through the communication channel using a known polarization. A receiver receives the signal and determines a symmetry characteristic of the polarization pattern of the received signal. The symmetry characteristic is matched to a stored symmetry characteristic to determine the composition of the object. Based on the composition of the object, the susceptibility of the wireless communication channel to wind-induced fading can be determined.

Abstract: An antenna system enabling a link between an airborne object sending out a signal E with any polarization and a moving body equipped with a dual-polarization antenna comprises at least one device to determine the position of the moving body and of the airborne object, and an assembly for positioning the antenna. The system comprises at least one polarization combiner receiving two signals H and V coming from the dual-polarization antenna, the signals H and V resulting from the signal coming from the airborne object; the combiner being adapted to recombining the signals H and V in order to obtain a signal E optimizing the link balance between the moving body and the airborne object.

Abstract: The present invention relates to a system for tilting polarization and steering main beam of airship antenna comprises: a 1st GPS receiver, which is located in the airship; a 2nd GPS receiver, which is located in the ground station; an airship antenna database for extracting the radiation pattern information of airship antenna and polarization information according to the posture of the antenna based on the position information of the airship; a ground station antenna database for extracting the radiation pattern information of ground station antenna and polarization information according to the posture of the antenna based on the position information of the ground station; a polarization and main beam direction correction operating device for computing the correction value of polarization and main beam direction of the airship antenna and the ground station antenna based on the position information of the airship and the ground station received from the 1st GPS receiver and the 2nd GPS receiver; and an airsh

Abstract: A broadband, 4-bit MMIC phase shifter for use in a phased array antenna is provided. The four bit selectable phase shifter for use in a phased array antenna of the present invention, which selectably causes an input signal to be shifted in phase, includes a first bit for selectively providing a 180° phase shift, wherein the first bit is a line/reflected bit; a second bit for selectively providing a 90° phase shift, wherein the second bit is a reflected bit; a third bit for selectively providing a 45° phase shift, wherein the third bit is a reflected bit; and a fourth bit for selectively providing a 22.5° phase shift, wherein the fourth bit is a high pass/low pass bit. The phase shifter of the present invention is compact, broadband and has good insertion loss and balance, yet uses a standard 0.25 mm PHEMT process with standard bias voltages.

Abstract: A satellite location determination system for a constellation of satellites includes a plurality of optical transceivers. Each optical transceiver is associated with a respective satellite and includes an optical synthesizer, transmission conditioning optics, a telescope assembly, reception conditioning optics, and an optical to electronic signal converter. The optical synthesizer produces phase-coherent optical laser pulses. The transmission conditioning optics appropriately conditions the characteristics of the phase-coherent optical laser pulses. The telescope assembly receives an output of the transmission conditioning optics and transmits an optical transceiver output into space for reception by an optical transceiver associated with another of the satellites. The telescope assembly also receives an optical transceiver output from another of the satellites. Reception conditioning optics appropriately conditions the characteristics of the optical transceiver output received from another of the satellites.

Abstract: A dual-polarization common aperture antenna having fully populated common aperture dual polarized arrays. The inventive antenna includes a first and second arrays of radiating slots disposed in a faceplate. The second array is generally orthogonal and therefor cross-polarized relative to the first array. The first array is waveguide fed and the second array is stripline fed. In the illustrative implementation, the first array and the second array share a common aperture. The common aperture is fully populated and each array uses the aperture in its entirety. The first and second arrays of slots are arranged for four-way symmetry. Each slot in the first array is a vertically oriented, iris-excited shunt slot fed by a rectangular waveguide and centered on a broad wall thereof. The second array is a standing wave array in which each slot is an air cavity backed slot fed by an inverted micro-stripline offset from a center thereof.

Abstract: An antenna system and an associated method are provided that are capable of providing improved cross-polarization isolation, thereby negating the otherwise deleterious effects of cross-coupling between orthogonally polarized signals that occur within a dual orthogonally polarized antenna, such as a phased array antenna. Thus, the antenna system can more reliably transmit and/or receive dual orthogonally polarized signals over a wide range of elevation and azimuth scan angles.

Abstract: An antenna array includes two pairs of linear polarized antennas mounted to a perimeter portion of an airframe with one pair having a polarization normal to the airframe and the other pair having a polarization tangential to the airframe. The antenna array eliminates the cross-polarization problem of an electromagnetic wave incident upon the array when using linear polarized perimeter mounted antennas.

Abstract: Method and device for enhancing performance of a base station (112) transceiver by detecting signal received from a mobile transceiver (140) by at least two antennas (H, V), thereby producing a plurality of received signal portions, determining the polarization of a signal transmitted to the mobile transceiver (140) according to the detected polarization characteristics, providing the reassembling the received signal from the received signal portions according to the detected polarization characteristics and alternatively dithering the polarization of the transmitted signal.

Abstract: A planar, ray-imaging, electronically steered array antenna, whose radiating array elements are disposed on a planar surface above an electrically conductive ground plane that enhances the antenna gain. The conductive ground plane forms an integral part of the antenna, and the required dimensions of this ground plane depend on the array height, and on the lowest elevation coverage angle from the (possibly tilted) ground plane. The antenna is further characterized by a modular design that tailors the required antenna gain and azimuthal directivity through the stacking of identical antenna segments side by side. The antenna can generate, with the aid of a multiple-beam microwave network or a two-ended series-feed network, a pair of symmetrically steered beams from an incident wavefront received by a linear (column) or planar array, in conjunction with reflections from a bottom metal plate.

Abstract: A solid state active aperture high power polarization agile transmitter, either single or dual polarization, employing nonreciprocal antenna elements, designed such that it can be used in an Electronic Warfare (EW) system that is more efficient and less expensive. Antenna beam steering is accomplished with variable phase shifters that are used to set the RF signal phase of each element. The beam steering function is implemented with a hardware architecture where the phase shifters are built-in ahead of the power amplifiers such that these low power phase shifters impart phase delays to low power signals without wasting RF signal power and hence improving efficiency. These power transmitter devices are also more reliable, lighter in weight and smaller in size.

Abstract: An antenna system and an associated method are provided that are capable of providing improved cross-polarization isolation, thereby negating the otherwise deleterious effects of cross-coupling between orthogonally polarized signals that occur within a dual orthogonally polarized antenna, such as a phased array antenna. Thus, the antenna system can more reliably transmit and/or receive dual orthogonally polarized signals over a wide range of elevation and azimuth scan angles.

Abstract: A method for aligning an antenna polarization axes of a dual polarized end-user terminal having an antenna. The antenna is aligned with a satellite in relation to azimuth and elevation. The end-user terminal is configured in an alignment mode to produce a first output corresponding to a first component of a received signal parallel to a first polarization axis of the antenna and a second output corresponding to a second component of the received signal parallel to a second polarization axis of the antenna. The first polarization axis is orthogonal to the second polarization axis. The method includes the steps of: receiving a linearly polarized signal; autocorrelating the first output and the second output to produce a measurement of autocorrelation; and adjusting the antenna polarization axes to minimize the measurement of autocorrelation.

Abstract: A digital polarimeter employs a signal time stretching technique to apply polarization phase shift characteristics to digitally generated polarization agile signal components. An RF signal to be transmitted is down-converted to an intermediate frequency and digitally sampled at a rate feasible with currently-available analog-to-digital converters. Horizontal and vertical signal components of the sampled IF signal are generated by processing the digital signal samples. Each digital signal sample is “time stretched” by storing each sample in M memory locations, such that N samples occupy M×N memory locations. Because each sample is stored in M memory locations, each incremental phase shift from one memory location to the next corresponds to 1/Mth of the actual sampling interval. The stretching process effectively increases the digital sampling frequency, yielding sufficient phase resolution.

Abstract: A method of determining the position of a satellite in a near geosynchronous orbit includes receiving at least one main lobe signal from an antenna on a first GPS satellite. A GPS signal, including GPS time and Doppler, is received from a pseudolite positioned on the Earth and an approximate position of each of a plurality of second GPS satellites is determined from an onboard almanac. Side lobe signals and accompanying noise are received from antennas on the plurality of second GPS satellites. The GPS signal and known sequential data bits are used for sorting or integrating the side lobe signals from the accompanying noise and the position of the satellite in a near geosynchronous orbit is determined using the one or more main lobe signals and the sorted side lobe signals.

Abstract: The present invention utilizes a dual polarization reception system (200) that utilizes the energy available in orthogonal polarizations to effectively increase link margin, thereby allowing for adequate signal quality reception in difficult environments. A co-polarized and a cross-polarized signal are separately downconverted and demultiplexed. The signals from each demultiplexed output are then sampled and weighted. The weighted samples for each polarity are combined in soft decision combining/decoding circuitry (255, 360), and this circuitry determines the most likely state of a received symbol's transmitted value.

Abstract: A system and method providing narrow antenna beam polarity and/or angular diversity for subscriber stations in a point-to-multipoint RF data transmission system employs a subscriber multibeam antenna. Coangular pairs of antenna beams have orthogonal polarity and each pair is angularly diverse. The subscriber transceiver uses a plurality of inputs and at least one output. Polarization diversity for a subscriber is provided by employing one of the coangular pairs of antenna beams to receive corresponding polarization diverse signals from a hub. Angular diversity is provided by receiving transmissions on two angularly diverse beams from two hubs. At a hub the bit error rate of transmissions from a subscriber and/or signal levels of available frequencies with different polarizations are monitored and the optimal beam, frequency and polarization for transmissions from the subscriber are determined. Changes in frequency, beam or polarization for transmissions to the hub are communicated to the subscriber.

Abstract: The base station has an antenna system comprising a housing for fixing it to a support and one or several radiating slots. It is designed for transmitting, in a first direction substantially perpendicular to the front surface of the housing, an electric field with polarization oriented along a second direction substantially parallel to the front surface, and for transmitting, in another direction closer to the second than to the first direction, an electric field with polarization substantially oriented along the first direction. The base station is well adapted to indoor environments in microcells or picocells. It can be fixed vertically on a wall or be horizontally suspended to a ceiling, without requiring separate antenna systems for these two installation modes.

Abstract: A planar, ray-imaging, electronically steered array antenna, whose radiating array elements are disposed on a planar surface above an electrically conductive ground plane that enhances the antenna gain. The conductive ground plane forms an integral part of the antenna, and the required dimensions of this ground plane depend on the array height, and on the lowest elevation coverage angle from the (possibly tilted) ground plane. The antenna is further characterized by a modular design that tailors the required antenna gain and azimuthal directivity through the stacking of identical antenna segments side by side. The antenna can generate, with the aid of a multiple-beam microwave network or a two-ended series-feed network, a pair of symmetrically steered beams from an incident wavefront received by a linear (column) or planar array, in conjunction with reflections from a bottom metal plate.

Abstract: A system and method for dynamically varying traffic channel sectorization within a spread spectrum communication system is disclosed herein. In a preferred implementation, the system is operative to convey information to at least one specified user in a spread spectrum communication system and includes a first network for generating, at a predetermined chip rate, a first pseudorandom noise (PN) signal of a first predetermined PN code. The first PN signal is then combined with a first information signal in order to provide a resultant first modulation signal. The system further includes a second network for providing a second modulation signal by delaying the first modulation signal by a predetermined delay inversely related to the PN chip rate. A switching transmission network is disposed to selectively transmit the first and second modulation signals respectively to first and second coverage areas.

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 directivity antennas each directed to 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: An antenna driving circuit for connecting an antenna to two transmitters is disclosed. The antenna driving circuit includes a hybrid combiner that has two isolated inputs. The hybrid is configured so that when a first signal is input to the first input, substantially one half of the energy of the first signal is output at the first output and the first signal is phase shifted by about −90 degrees at the first output. Substantially one half of the energy of the first signal is output at the second output and the first signal is phase shifted by about 0 degrees at the second output. When a second signal is input to the second input, substantially one half of the energy of the second signal is output at the second output and the second signal is phase shifted by about −90 degrees at the second output. Substantially one half of the energy of the second signal is output at the first output and the second signal is phase shifted by about 0 degrees at the first output.

Abstract: The disclosure relates to a process of cyclic detection in diversity of polarization of digital cyclostationary radioelectric signals. The process consists in acquiring the signals on a network of at least two of antennas, in calculating a cyclic covariance matrix on a first moment, and on a second moment, of a spectral correlation of the digital signals acquired, and in detecting peaks of spectral correlation by comparing a likelihood ratio with a detection threshold determined statistically. The invention is applicable notably to digital radioelectric signals emitted by a satellite.

Abstract: A duplex polarization adaptive system is described. The system provides polarization diversity for base station antennas under both receive and transmitting conditions. Since the base station provides polarization diversity in both transmit and receive modes, no polarization diversity is needed in the handheld unit. Even though the handheld unit does not provide polarization diversity, a duplex communication system, that uses polarization diversity for both the uplink and the downlink is provided, because the base station provides polarization diversity for the uplink and the downlink paths. By installing the two-way diversity at the base station, the overall cost of implementing diversity is reduced because one base station can typically serve many handsets. The base station antenna determines the polarization state of signals received from a remote unit, such as a handheld unit, using a polarization diverse antenna system. The base station then transmits using the same polarization state.

Abstract: A microwave receiving antenna system (30) is described which is used to determine an originating direction of microwave radiation. The system has a birefringement phase plate (34) which splits radiation incident on it into two components which undergo a differential phase delay as they pass through it. The amount of differential phase delay induced varies with angular position around the phase plate (34) from 0 at an angular position of 0° to &lgr; an angular position of 360°. By determining the differential phase delay (assuming a previously existing relationship) the originating direction of the radiation can be determined.

Abstract: Methods for automatically detecting GPS hardware are provided. The methods attempt to determine the protocol of a GPS receiver by adjusting variables related to the protocol of the GPS receiver. The variables may include baud rate, protocol, or any other desired variable. Following determination of the proper configuration settings, the methods determine the communications port to configure with the appropriate settings.

Abstract: The invention includes methods and systems to improve the signal diversity between a repeater and a base station in a wireless communication system. A communications device transmits a wireless signal. The repeater receives two versions of the wireless signal using a first receiver system and a second receiver system. The repeater transmits two versions of the wireless signal that correspond to the two received versions. The repeater transmits the two versions with different signal polarizations so they can be isolated from one another at the base station. The base station receives the two versions from the repeater and isolates each version based on the difference in polarization. The base station processes the two diverse versions to produce a high-quality signal. The use of different polarizations to provide diverse signals between the repeater and the base station lowers signal power requirements and increases the capacity of CDMA systems.

Abstract: A receiving system 100 is disclosed which includes at least one antenna 101 providing a plurality of antenna beams providing signal diversity between communicated signals. A first processing branch 103 is included for processing a first plurality of signals appearing within a first plurality of the antenna beams. The first processing branch 103 includes a plurality of signal paths, some of which include delays 105, each receiving a one of the first plurality of signals from a corresponding one of the first plurality of antenna beams. Delays 105 apply a predetermined amount of delay proportionate to the corresponding one of the beams. First processing branch 103 further includes a combiner 106 for combining the first plurality of signals after output from the plurality of signal paths. A second processing branch 104 is provided for processing a second plurality of signals appearing within a second plurality of the antenna beams.

Abstract: The information signals are transferred to end users, customers, or service subscribers using at least two signal sources, generally satellites, and polarized radiation. Two polarization modes are employed, with the preferred modes being left-hand and right-hand circularly polarized radiation, although other polarization modes may be employed. The total number of channels can be divided among the polarization modes and transferred to end users either through the use of polarization switching in the receivers to selectively switch between the satellites, or by switching elements in the satellites (sources) to switch between polarization modes used for transmission.

Abstract: A beam forming network having a division network for a hexagonal structure of elements, where the neighboring elements in the same column, having the same primary polarization, have three-way power division. The neighboring elements in adjacent columns, having a different primary polarization, have four-way power division. In the combining network, seven signals are combined from outputs of elements having the same polarization. Three of the signals will come from adjacent elements in the same column, and four signals will come from feeds in adjacent columns that are diagonal to the center element. The overlapping element configuration covers a large geographical area with reduced interference between neighboring elements. A waveguide implementation of the beam-forming network of the present invention is provided in which waveguides are structures so as to avoid crossovers, thereby eliminating interference and simplifying construction and assembly techniques.

Abstract: Problems of fading in a multi-path environment are ameliorated, and the presence of reflective surfaces is turned from a disadvantage to an advantage, by employing a third polarization direction that effectively creates a third communication channel. This third communication channel can be used to send more information, or to send information with enhanced spatial diversity to thereby improve the overall communication performance. A transmitted signal with three polarization directions is created with a transmitter having, illustratively, three dipole antennas that are spatially orthogonal to each other. A received signal having energy content in three polarization directions is detected by a receiver having, illustratively, three dipole antennas that are spatially orthogonal to each other.

Abstract: An antenna array system includes a first array for operating in a transmit mode and a receive mode and a second array spaced apart for operating in the receive mode. A receiver adjusts a receive radiation pattern in the receive mode and provides a control signal for a transmit radiation pattern of the transmit mode.

Abstract: The antenna for receiving and/or transmitting linearly polarized signals includes at least a first radiating element (24, 26) circularly polarized in one direction and at least a second radiating element (28, 30) circularly polarized in the other direction. The signals with substantially equal amplitudes supplied by the radiating elements circularly polarized in opposite directions are combined to supply a linearly polarized signal. The linear polarization direction is a function of the variable phase-shift (&Dgr;&phgr;) between the combined signals. A phase-shifter (32) adjusts the polarization direction of the antenna. The adjustment can be automated.

Abstract: A method and apparatus for generating microwave signal frequencies. An incident reference signal is provided. A first stimulus signal is also provided, the first stimulus signal having a first polarization and having a first predetermined relationship with the incident reference signal. A second stimulus signal is also provided, the second stimulus signal having a second polarization and having a second predetermined relationship with the incident reference signal. The incident reference signal is split into a first polarization reference signal and into a second polarization reference signal. The first stimulus signal is coupled with the first polarization reference signal to provide first polarization mixed signals. The second stimulus signal is coupled with the second polarization reference signal to provide second polarization mixed signals.

Abstract: To improve null depths in an antenna pattern of a first polarization, formed with nulls in at least one angular region, a further antenna pattern of a second polarization, substantially orthogonal to the first polarization, is concurrently formed. In the angular region, the amplitudes of the copolar components of the further antenna pattern are substantially equal to the amplitudes of the crosspolar components of the antenna pattern of the first polarization, and the phases of the copolar components of the further antenna pattern of the second polarization are substantially opposite to the phases of the crosspolar component of the first polarization.

Abstract: A demodulator with a cross polarization interference canceling function for canceling interference of cross polarization in the main polarization includes a demodulating unit for demodulating a baseband signal of the main polarization, a phase control unit which controls the phase of an interference signal, which is a baseband signal of cross polarization, based upon an error in the demodulated signal, and an interference cancellation unit which cancels an interference signal component from the demodulated signal of the main polarization.

Abstract: A method for processing received radio signals that are subject to unwanted change during propagation through the atmosphere, from a transmitter to a receiver array. The multiple signals are received as cochannel signals at the antenna array, and are processed to eliminate the effects of modification of the signals during propagation, wherein the processing step includes cumulant-based signal recovery without regard for the geometrical properties of the antenna array. In the invention as disclosed, two different information signals having two different polarization states are transmitted, and at least one of the transmitted signals is subjected to an unwanted change of its polarization state. The received signals are processed to separate and recover the two information signals without regard to their polarization states.

Abstract: A communications system in which a communications channel is defined at least in part by an electromagnetic wave having a carrier frequency and an electric field vector, the extremity of which traces a non-linear periodic path at a second frequency between the carrier frequency and zero from the perspective of an observer looking into the axis of propagation of the wave. The transmitter of the communications system launches a wave having such characteristics and modulated with information in a suitable manner. The receiver of the communications system is sensitive to the periodic path and second frequency. Either the periodic path, the second frequency, or both provide selectivity that can be used to define multiple communications channels.

Abstract: An antenna feed for a 94 GHz radar combining quasi-optic and microwave integrated circuit (MIC) techniques. The optical components (15-23) couple MIC receive and transmit boards (FIGS. 2, 3 and 4) to the antenna, which may be a steerable cassegrain. Co-polar and cross-polar received signals are coupled out of the optical system by transmitting/reflecting grids (3 and 5) and the transmit signal may be similarly coupled into it (7). The MIC's have antenna patch arrays which are oriented to suit the respective polarization plane and associated grid. The use of a Faraday rotator (17) in conjunction with a grid (5) in the optic path permits spearation of the transmit path (13) from the receive path (25), each then having it own MIC (FIG. 4 and FIG. 3). Alternatively, duplexing is performed in a common MIC (FIG. 6).

Abstract: Problems of fading in a multi-path environment are ameliorated, and the presence of reflective surfaces is turned from a disadvantage to an advantage, by employing a third polarization direction that effectively creates a third communication channel. This third communication channel can be used to send more information, or to send information with enhanced spatial diversity to thereby improve the overall communication performance. A transmitted signal with three polarization directions is created with a transmitter having, illustratively, three dipole antennas that are spatially orthogonal to each other. To take advantage of the signal with the third polarization direction, the receiver also comprises three mutually orthogonal antenna dipoles.

Abstract: GPS receivers are provided that reduce all types of interference signals with a simple receiver structure that includes an antenna system having a reference antenna element and a plurality of auxiliary antenna elements, a plurality of phase shifters and a power combiner. The receiver also includes a downconverter, a digital GPS processor and an analog-to-digital converter (ADC). Each antenna element generates a single output signal in response to all polarization components of a GPS signal. In response to a composite signal of interference signals and GPS signals, the reference antenna element provides a reference signal and the auxiliary antenna elements provide auxiliary signals which each has a phase difference from the reference signal that is a function of its respective auxiliary antenna element's location in an antenna array space and of paths of the interference signals.

Abstract: An array antenna for use in, e.g., a radar includes a plurality of pairs of vertical polarization antenna elements and horizontal polarization antenna elements. A particular transmission/receipt module is connected to each pair of vertical and horizontal polarization antenna elements. A beam controller forms a transmission/receipt digital beam while a local signal generator controls a transmission/receipt frequency. The beam controller is connected to the transmission/receipt modules via a data bus and I/O (Input/Output) sections included in the modules.

Abstract: Positioning system for locating a mobile body comprising a plurality of earth based spread spectrum (SS) broadcasting stations arranged geographically in a cellular pattern. Each SS broadcasting station include a modulator providing a channel signal structure which is substantially orthogonal with respect to adjacent stations in the cellular pattern, each channel signal including navigation beacon data including a unique beacon identification, station latitude and longitude, time.sub.-- slot and phase characterizations and selected parameters of adjacent stations. In one embodiment, each modulator provides a chirped SS signal in which the navigation beacon is a frequency tone that is repeatedly swept over a selected frequency band for each station. In a further embodiment, each modulator provides a GPS like direct sequence SS signal in which the navigation beacon is a PN coded broadcast.

Abstract: A beam forming apparatus and method for forming a plurality of directional beams within a sector, as well as a full sector coverage beam is disclosed, wherein uplink reception diversity is maintained, through provision of a either a single facet antenna or a pair of single facet antennas. Two implementations are disclosed: a first implementation employs orthogonal polarization diversity from a single antenna facet, whereas a second implementation employs space diversity from a pair of spaced apart antenna facets. A first implementation employing polarization diversity comprises an antenna having an array of dipole pairs, dipoles of each pair being positioned orthogonally from each other. The dipole pairs are driven on a downlink, to form a plurality of directional beams having first polarization, and a full sector coverage beam having second polarization.

Abstract: Positioning system for locating a mobile body comprising a plurality of earth based spread spectrum (SS) broadcasting stations arranged geographically in a cellular pattern. Each SS broadcasting station include a modulator providing a channel signal structure which is substantially orthogonal with respect to adjacent stations in the cellular pattern, each channel signal including navigation beacon data including a unique beacon identification, station latitude and longitude, time_slot and phase characterizations and selected parameters of adjacent stations. In one embodiment, each modulator provides a chirped SS signal in which the navigation beacon is a frequency tone that is repeatedly swept over a selected frequency band for each station. In a further embodiment, each modulator provides a GPS like direct sequence SS signal in which the navigation beacon is a PN coded broadcast.