Abstract: This invention reduces the number of amplifiers needed and thus reduces the weight of a multi-beam transmitting system. Each input beam is connected respectively to each switched terminal of an input switch. The fixed terminal of the input switch is connected to the input of an amplifier the output of which is connected to the fixed terminal of an output switch. Each switched terminal of the output switch is connected respectively to transmit feeds which are located off-set from the prime focus of a transmit reflector antenna. Both the input and the output switches are switched synchronously. The invention includes MMIC and high Tc superconducting transmit systems. The invention includes design to prevent single point failures and a design to transmit a large amount of RF power.

Abstract: The footprint of a first satellite is reconfigurable in orbit by ground control to switch on and off different transponders. Each transponder is connected to a corresponding downlink antenna feed, each of which transmits a downlink beam independent of the others. The satellite can be moved into different orbits or otherwise changed to service new geographic areas by using different combinations of the transponders. In one embodiment, the satellite includes an antenna and components for an uplink beam corresponding to each downlink beam. Various subsets of the downlink antenna feeds are mechanically linked to move in unison using gimbals, each subset using a corresponding gimbal and mechanical driver. The first satellite is sufficiently reconfigurable that it may serve as a back up satellite to a plurality of other satellites in a constellation of satellites.

Abstract: An antenna system (1) transmits return signals, for example, in the band Ka, based on signals received from a distribution network in the band from 2.5-3 GHz. The return signals are transmitted through the network from a user receiver (PC) with a frequency lying below 65 MHz, they are processed in a frequency converter (up-C) between the network and the antenna system so as to be delivered to the antenna system with a frequency lying in the 2.5-3 GHz band, and frequency management data received in the downstream channel are used in the frequency converter (up-C) for selecting the frequency in the 2.5-3 GHz band.

Abstract: A system and method for providing a global positioning system (GPS) enabled antenna system are provided. The GPS enabled antenna may be used, for example, on a wireless communications device such as a wireless handset. The wireless communications device includes a GPS switching module coupled to a conventional communications antenna, including its associated circuitry. The GPS switching module is adapted to selectively couple the communications antenna to GPS matching circuitry. In this arrangement, the GPS matching circuitry adjusts impedance at approximately 1575 MHz to more closely match the communications antenna to GPS circuitry in the wireless device.

Abstract: The present invention relates to a method for adaptively controlling a transmission radiation pattern. Radio signals coming through a plurality of paths are received and demodulated for each path. The received level or received quality of each demodulated signal is compared to each other to select a signal with the highest level or most excellent quality. A path corresponding to a selected path is set at a path for transmission. When a plurality of signals each with an almost equal level or received quality exists in signals demodulated for each path, a history of transmission power control command (TPC) transmitted from a communication partner is referred. In other words, the reception condition in a communication partner is checked. Thereby, it is judged whether or not the currently selected path is appropriate as the path for transmission.

Abstract: An combined satellite and terrestrial antenna system for a structure is disclosed. The antenna system that includes a terrestrial antenna, a satellite antenna, a satellite receiver, and an AM/FM receiver. The terrestrial antenna includes a multi-band terrestrial antenna mounted on a mounting assembly including a low noise amplifier circuit and a bezel. The bezel is adapted to contain the low noise amplifier. The satellite antenna is concentrically mounted with respect to the terrestrial antenna. The mounting assembly is connected to the satellite receiver for reception of satellite and satellite retransmitted signals by a satellite-terrestrial-retransmitted-satellite cable. The mounting assembly is also connected to the AM/FM receiver for reception of AM/FM terrestrial signals by a terrestrial AM/FM cable. A method for mounting the combined satellite and terrestrial antenna system on a structure is also disclosed.

Abstract: To provide an antenna unit in which a coaxial cable is firmly connected and fixed to an antenna substrate by an easy soldering process and freedom in pattern formation and mounting of parts on the antenna substrate is improved.

Abstract: A satellite communications system uses multiple ground stations and one or more satellites for communicating between mobile subscribers and a land-based communications network, such as the PSTN or the Internet. Multiple ground stations geographically dispersed minimize toll charges incurred routing calls from a mobile subscriber through the land network by reducing the need for long-distance calling. Further, because each ground station communicates with a given satellite using the same frequency spectrum, the subscriber capacity of the system increases and/or bandwidth requirements for the communications link between ground stations and satellites may be reduced. The present system uses ground-based beamforming techniques enabling each satellite to transmit signals in multiple transmission beams, each beam supporting one or more mobile subscribers. Each beam may reuse the same frequency spectrum, thereby increasing the number of subscribers supported by each satellite.

Abstract: An LNB (low noise block down converter) that can have a plurality of receivers connected includes a conversion unit receiving a plurality of types of polarized wave signals transmitted from each of a plurality of satellites to convert the plurality of polarized wave signals into a plurality of intermediate frequency signals, an amplify switch connected to the conversion unit to receive the plurality of intermediate frequency signals as inputs, and having a plurality of outputs connected to a plurality of output ports, respectively, determining a status according to a select signal and providing an amplified intermediate frequency signal, and a first control unit receiving digital serial data to select a satellite from an external source via an output port and providing a select signal according to the digital serial data.

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 satellite communications system uses multiple ground stations and one or more satellites for communicating between mobile subscribers and a land-based communications network, such as the PSTN or the Internet. Multiple ground stations geographically dispersed minimize toll charges incurred routing calls from a mobile subscriber through the land network by reducing the need for long-distance calling. Further, because each ground station communicates with a given satellite using the same frequency spectrum, the subscriber capacity of the system increases and/or bandwidth requirements for the communications link between ground stations and satellites may be reduced. The present system uses ground-based beamforming techniques enabling each satellite to transmit signals in multiple transmission beams, each beam supporting one or more mobile subscribers. Each beam may reuse the same frequency spectrum, thereby increasing the number of subscribers supported by each satellite.

Abstract: A method within and wireless communications unit (WCU) arranged to operate in a fixed wireless network including a transceiver for receiving and transmitting signals within the network; an antenna system having adjustable visibility to the fixed wireless network; and a controller, coupled to the transceiver and the antenna system, to control the transceiver and to adjust the visibility of the antenna system such that the visibility of the WCU to the fixed wireless network is adjustable.

Abstract: A communications payload configuration comprising a multi-port amplifier that incorporates remotely controllable travelling wave tube amplifiers (TWTAs) for allowing their output power to be adjusted depending on the traffic demand and the payload operational conditions. The power delivered by each TWTA is controlled by adjusting the TWTA anode voltage in response to a command signal received from the ground station. If a TWTA fails, the power delivered by each of the remaining TWTAs is increased by gross anode voltage control. The power lost by the failure is thus recovered by increasing the power of the remaining TWTAs. This power control is done in a constant efficiency way by also readjusting the TWTA collector voltages.

Abstract: Mechanisms for selecting a set of antennas for use in a wireless communication system are disclosed. The selected set of antennas is for use in communicating data in a wireless local area network (WLAN) comprising an access point and a plurality of mobile stations. The access point includes a baseband chip capable of adapting various radio frequency (RF) units. Each RF unit in turns includes a plurality of RF sub units, each of which connects to a plurality of antennas. The access point thus includes a number of antennas that, together with the RF units and the baseband chip, form a smart antenna. To identify the selected set of antennas to communicate with a particular mobile station, the access point initially uses a first set of antennas each in a RF sub unit. From this first set of antennas, the access point identifies a first set of winner antennas and a first set of non-winner antennas.

Abstract: An antenna system which is capable of having omnidirectional transmitting and receiving capabilities is disclosed. The antenna system includes a plurality of directional antennas coupled to a transceiver, wherein the antennas are configured to have their main lobes extend in different directions. In a specific embodiment, there are six directional antennas configured to have their main lobes extend substantially along the positive and negative x-axes, the positive and negative y-axes, and the positive and negative z-axes of a three-dimensional Cartesian system. The six directional antennas may also be configured to transmit and receive signals to and from overlapping free space regions to give it omnidirectional coverage. Also disclosed are a network device which employs such antenna system, a wireless network system which employs a plurality of network devices each having such antenna system, and a method and software module to transmit and receive data using such antenna system.

Abstract: A system and method for adjusting satellite communication signal transmit power for signals transmitted to a localized region within a satellite coverage area utilize real-time information on weather conditions (172) and/or actual path losses (174) within the localized regions to adjust the effective isotropic radiated power (EIRP) of the satellite beams (188) to minimize the total radio frequency (RF) power required for transmission. The transmission system may be realized using a variety of antenna types for transmitting spot beams and/or area coverage beams. Representative antenna implementations include multi-beam antennas having a low-level beamforming network and hybrid matrix amplifier system, phased-array with independent input amplitude control and beamsteering for each beam, and a phased-array feeding a confocal imaging system for single broadcast beam per polarization.

Abstract: A communication system transmits and receives communications within a sectorized cell between at least one primary station and at least one secondary station. The communication system includes a unit for generating and shaping a beam; an antenna for transmitting and receiving signals within said beam; and a unit for directing the beam. The shaped beam is directed at a plurality of predetermined directions; either continuously or discretely.

Abstract: A power system for a satellite includes a high power amplifier that has a control input. The high power amplifier has a minimum effective isotropic radiated power. A controller is coupled to the control input. The controller generates a control signal to adjust a saturated power output of the high power amplifier to the minimum effective isotropic radiated power.

Abstract: A satellite system includes a plurality of orbit slots having a first orbital and a second orbital slot. A first satellite occupies a first orbital slot and generates a first set of uniform beams. A second satellite located in a second orbital slot generates a second set of uniform beams. A tiling pattern on the face of the Earth has a plurality of cells, with each of the cells having a defined frequency for communication. The first set of beams and the second set of beams are generated according to parameters to avoid interference between them. The parameters may include satellite orbit separations, beam size, multiplicity of band reuse, and ground station received beamwidth.

Abstract: A reception signal of a horizontally polarized wave and a reception signal of a vertically polarized wave from one satellite are amplified by a first pair of low noise amplifiers, and a reception signal of a horizontally polarized wave and a reception signal of a vertically polarized wave from another satellite are amplified by a second pair of low noise amplifiers. One of the low noise amplifiers is selected in accordance with the polarized wave and the satellite, and the signal from the selected low noise amplifier is supplied to a further low noise amplifier through a coupling circuit. The coupling circuit includes extending portions extended in strip conductor shapes from the first pair of low noise amplifiers and an extending element extended in a strip conductor shape from an input of the next stage low noise amplifier. The extending portions and the extended element are arranged so as to closely face each other.

Abstract: The system comprises transmitters transmitting programs or multimedia data to a satellite, each program being transmitted on an uplink frequency channel, and program multiplexing means onboard the satellite receiving programs and routing them onto a single downlink frequency channel. A configuration station on the ground comprises means for transmitting system data on an uplink frequency channel and configuration means onboard the satellite selectively associate uplink frequency channels and a downlink frequency channel in response to some of the received system data.

Abstract: A communication system including a first transceiver located on a first platform at a predetermined altitude. A first antenna is located on the first platform and connected to the first transceiver. A second antenna is connected to the other end of the first transceiver. A second transceiver is located on a ground hub physically and independent of the first platform. A third antenna is located on the ground hub and connected to the second transceiver. The third antenna is adapted to communicate with the second antenna. The first platform is maintained in a stratospheric orbit. A beamforming system is connected to the second transceiver and mounted on the ground hub. The beamforming system provides a beamformed signal from the second transceiver to the first transceiver effective to drive the first array antenna to radiate multiple beams to a surface, whereby the multiple beams create time varying and dissimilar footprints thereon.

Abstract: A scalable switch matrix and demodulator bank architecture for a satellite payload processor wherein the demodulators are connected to the output ports of the switches as the data load on the uplink beams varies. The switch matrix includes a first switch layer for receiving the uplink transmission beams and a plurality of demodulators connected to the output parts of the first switch layer. The number of demodulators is limited by the number of active uplink sub-bands which is generally less than the number of sub-bands per beam times the number of transmission beams. Thus, only a relatively few number of demodulators are distributed among the uplink transmission beams as required. This results in a readily scalable architecture having higher demodulation utilization rates than dedicated demodulation architectures.

Abstract: A “power adaptive circular” (PAC) transmission scheme that can support both spatial multiplexing and transmit diversity for multi-carrier MIMO systems and has a number of desirable characteristics, including the ability to: transmit a variable number of symbol streams, provide transmit diversity for each transmitted symbol stream, support coded interference estimation technique at a receiver, and use power efficiently. In one method, at least one stream of symbols is received for transmission on a plurality of subbands and from a plurality of antennas. The at least one stream of symbols is multiplexed such that (1) the symbols in each stream are transmitted from the plurality of antennas (e.g., diagonally across the subbands and antennas) and (2) the at least one stream starts in the same subband. A stream of multiplexed symbols is formed for each antenna and further processed, and may be transmitted at full power available for the antenna.

Abstract: A wireless network includes a satellite antenna assembly with a reflector dish and at least one low-noise block converter (LNB) positioned opposite the reflector dish. A wireless transceiver transmits video and data information to one or more users located in a surrounding area. An interface unit is coupled to provide communication signals to the wireless transceiver. The unit is also configured for connection to an interactive data network so that the one or more users are provided with connectivity to the interactive data network via the wireless transceiver. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted With the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.72(b).

Abstract: Wireless communication methods and systems using multiple sectored cells. In one example, each cell of a cellular coverage area is divided into a number of sectors. A number of different half duplex or full duplex channels are used in each cell to communicate between a base station and a number of subscriber stations located in the cell. At least some of the channels may be reused in other cells of the coverage area. Additionally, some channels may be reused both amongst sectors of a given cell and in other cells of the coverage area. The sectored cells are arranged with respect to one other such that interference amongst similarly oriented sectors of different cells using one or more same channels is reduced.

Abstract: A method and device for using a single antenna for simultaneously receiving radio frequency signals in different L-band and GPS data band radio frequency bands embodied by example in a circuit having a directional coupler configured to direct a signal input at a first port into two second ports. Filters are coupled to receive the output of each second port, the filters being configured to reflect radio frequency energy in radio frequency bands other than the GPS data radio frequency band. The directional coupler is further configured to direct the reflected radio frequency energy into another port of the directional coupler. A filter is coupled to the other port of the directional coupler and is configured to reflect radio frequency energy in radio frequency bands other than the L-band radio frequency.

Abstract: An analog-to-digital (A/D) converter bank with digital down conversion (DDC) is used to substitute a very-high-speed A/D converter for the UWB transceiver. The A/D converter bank has flexibility and scalability operation functions including the number of low-speed A/D converters, adaptive amplifiers, digital FIR filters or one Mth frequency band digital FIR filter, with operating in parallel, as well as analyzed sequence and synthesized sequence switches. The A/D converter bank for the UWB transceiver has a aliasing free and does not have a phase distortion. The DDC, which has scalability to deal with a multirate operation, is used to shift bandpass signals into baseband signals and decimate the baseband signals according to different down samplings.

Abstract: A system for transmitting data to a plurality of satellites is provided. A first satellite in an orbital slot has an associated receive antenna, and is configured to receive signals in a first range of frequencies. A second satellite in the orbital slot has an associated receive antenna. The second satellite is separated from the first satellite by at least a first separation angle, and is configured to receive signals in the first range of frequencies. A first earth uplink antenna, located at a first earth location, is capable of transmitting a first uplink beam at the receive antenna of the first satellite. A second earth uplink antenna, collocated at the first earth location, is capable of transmitting a second uplink beam at the receive antenna of the second satellite. The first uplink beam includes first signals at the first range of frequencies, and the second uplink beam includes second signals at the first range of frequencies.

Abstract: A multilayer radio frequency interconnect apparatus includes a plurality of laminated printed wiring boards made of a dielectric material with low loss characteristics for radio frequency electromagnetic radiation. In operation, a RF signal launches from a first signal conductor 24. A vertical transition from the first signal conductor 24 to a second signal conductor 44 is realized by a 3-wire transmission line. The center conductor of the 3-wire transmission line is a RF via 30. The two outer conductors are RF ground vias 32 and connect the first RF ground conductor 22 to the second RF ground conductor 42. These two RF ground vias 32 are isolated from the ground planes 40, 46 which are located between RF signal layers 20, 38. The advantage of this ground isolation is to maintain the 3-wire transmission line characteristic impedance and to reduce disturbance to electromagnetic fields such that a broadband design may be achieved. The RF ground vias are terminated at signal layers 20, 38.

Abstract: A system and method of providing scalable beam coverage for satellite communications to ground terminals. A single antenna being adapted to provide an adjustable range of narrow to wide area coverage is provided and a density of ground terminals in the coverage area is determined. A required total beam data rate is determined and the antenna is adjusted to generate single or multiple beams of variable beamwidths that correspond to the field of view required and the transmitted power and linearity are adjusted to the proper levels as determined from the density of ground terminals and required total beam data rate. The required total beam data rate capacity remains essentially constant over the adjustable range of narrow to wide area coverage.

Abstract: A signal processing circuit for satellite communications signal includes a first one dimensional digital beam forming circuit for forming a beam signal in a first direction and a second one dimensional digital beam forming circuit for forming a beam in a second direction. A direction filtering circuit is coupled between the first one dimensional digital beam forming circuit and the second one dimensional digital beam forming circuit. The filtering circuit determining a communications signal direction of the satellite communications signal and tunes the filter to reduce a filter bandwidth and a frequency range of said beam signal prior to processing through the second one dimensional digital beam forming circuit.

Abstract: A diversity receiver with simplified construction, excellent receiving signal quality even with very low fading speeds wherein, on the basis of a signal from a receiving unit capable of detecting the receiving signal intensity, an antenna changeover is effected when the receiving signal intensity falls below a changeover threshold value. When, at the termination of a first lapse time from the first antenna changeover, the receiving signal intensity is below that immediately before the first antenna changeover, an antenna changeover is again effected and any antenna changeover is prevented from being effected for a second lapse time from the second changeover. The second lapse time is set to be longer than the first lapse time.

Abstract: A repeater is disclosed which is usable to permit a satellite phone, normally requiring a direct line of sight link to an orbiting satellite, to communicate with the satellite when the satellite phone is otherwise obstructed from communicating with the satellite. The repeater is usable in any situation in which the satellite phone is blocked from a direct line of site to the satellite, such as inside a building, aircraft, or natural formation (e.g., cave).

Abstract: The present invention is directed to cellular systems and methods for providing a multi-beam antenna configuration within a base station without utilizing duplex filters. The multi-beam antenna configuration of the present invention produces overlaid beams in both the uplink and downlink to cover the same area. Each beam has orthogonally oriented polarization directions (e.g., linear polarized slanted ±45°) for the uplink and downlink. Adjacent uplink beams shall also have shifted polarization directions in order to attain polarization diversity between different beams. In order to implement this polarization configuration, for each beam, there is a selective filter in front of the low noise amplifier for the uplink, and no duplex filter in front of the amplifier in the downlink direction.

Abstract: A satellite communications system (10) provides for digital beamforming acquisition. The communications system (10) has an antenna configuration (20) for maintaining communications links with satellite networking equipment, and a signal processing system (30) for processing signals resulting from the communications links. A beamforming subsystem (40) dynamically forms traffic beams and overhead beams, wherein the overhead beams scan overhead areas of the satellite footprint. Overhead areas are defined by areas of the satellite footprint without active traffic channels. The beamforming subsystem (40) includes a channel database configuration (50) containing traffic channel input data and overhead channel input data. A beamforming processor (60) converts the input data contained in the channel database configuration (50) into traffic beams schedules and overhead beam schedules. An antenna management system (70) dynamically forms traffic beams and overhead beams based on the beam schedules.

Abstract: A system and method for automatically directing a communication antenna to point to a desired wireless communication transceiver, is presented herein. The system includes a position location receiver, which receives signals indicating the position location information of the antenna and a position location transmitter and a processing mechanism, which determines calibration information of the antenna. The calibration information is achieved by first establishing a reference vector between the location of the antenna and position location transmitter and establishing a vector reference space and then calculate the necessary elevation and azimuthal components, within the vector reference space, to identify the proper calibration of the antenna. Once the calibration information has been determined, an alignment mechanism automatically orients the antenna.

Abstract: Amplitudes and phases of different channels in an electromagnetic signal transmission network, whereof the sources are arranged in a triangular lattice, are determined by tiling the lattice with hexagons having six equal sides, the hexagonal tiles that are formed are distributed on the lattice such that two successive tiles along a direction in the lattice rectangular height equivalent to the triangular lattice are offset by an elementary step along the width direction. A Fourier transform is performed on the resulting tiles; directions are selected on the resulting new lattice corresponding to the transmission directions; an inverse Fourier transform is performed of the directions; and amplitude and phase coefficients to be applied to the transmission network different channels are deduced from the inverse Fourier transform.

Abstract: An elliptical satellite communication system including a constellation of satellites which orbit the earth at a height less than that necessary for geosynchronous orbits but which simulate the characteristics of geosynchronous orbits. The satellites' velocity near the apogee portion of their orbit approximates the rotational velocity of the earth, and during that period appear to hover over the earth. The ground stations on the earth always communicate with a satellite at or near its apogee, and hence that satellite appears to the ground station to hover over the earth. During the times when the satellite is outside the apogee portion, its communication is shut off to prevent any possibility of interfering with geosynchronous satellites and its power supply is used to charge a battery on the satellite. Thus, the power supply of the system can be reduced by an amount equivalent to the percentage of time the satellite is not used.

Abstract: A transponder system, which may be on a spacecraft, provides communications to and among user terminals for audio-bandwidth signals. The transponder includes a receiver for uplink signals, and a digital channelizer which separates the various independent uplinked signals. The separated uplinked signals are then grouped together with other signals destined for the same downlink beam, and routed to the corresponding beam input port of a beamformer. The beamformer, in turn, energizes or feeds those antenna elements which are required to form the desired antenna beam. In order to provide a capability for handling signals having a bandwidth greater than that of the audio signals, as might be required for providing the capacity to handle Internet signals, for example, a wideband augmentation equipment (WAE) is coupled in such a manner as to bypass the digital channelizer, to thereby provide a wideband path through the system, bypassing the narrowband channelizer.

Abstract: A wireless repeater for repeating a wireless signal without necessarily transforming the wireless signal is provided. The wireless repeater includes a plurality of external antennas, each external antenna configured to operate within one or more wireless frequency bands. The wireless repeater includes a plurality of internal antennas, each internal antenna configured to operate within one or more wireless frequency bands associated with the external antennas. An amplifier unit is connected to the external antennas and internal antennas. The amplifier unit is configured to identify a frequency associated with an incoming wireless signal from within a plurality of wireless frequency bands. The amplifier unit also determines a signal strength for the incoming wireless signal and adjusts the signal strength of the incoming wireless signal to compensate for a loss in signal strength between the external antennas and the internal antennas.

Abstract: A method for transmitting a power control signal in a mobile communication system. By altering the power control subchannel, the method reduces the delay between power measurement and power control by one power control group (PCG) in comparison with the conventional method. The power control subchannel is moved within the power control group so that a time equal to generating the power control bit is before the power control bit and a time equal to the sum of the round-trip propagation delay between base station and mobile unit and the time needed to perform gain control is after the power control bit.

Abstract: A means and method to increase the beam traffic capacity, especially in high user density regions, of a multi-beam antenna communication system with multiple signals at any frequency transmitted (received) when in a transmit (receive) mode by canceling interference with neighboring signals. An interference cancellation network is provided for canceling the interference caused by the sidelobe(s) of at least one signal with one or more of the other signals in the network. Each power divider divides its input signal into one reference fractional signal and at least one non-reference fractional signal. Phase shifters/attenuators shift the phase and attenuate the amplitude of at least one of the non-reference fractional signals. Each power combiner combines its input reference fractional signal with at least one non-reference fractional signal into a composite signal emerging from the combiner. The phase/attenuation settings are selected to optimize the signal to interference ratio for each communications link.

Abstract: A satellite system is provided that includes a receive antenna system to receive one of C-band and/or Ku-band signals and a transmit antenna system to transmit one of C-band and/or Ku-band signals. A payload section may be coupled between the receive antenna system and the transmit antenna system. The satellite system may provide broadband communications at C-band and/or Ku-band.

Abstract: A ground-based antenna for use with a satellite communications (SATCOM) system that reduces interference from geosynchronous earth orbit (GEO) satellites. Because GEO satellites that provide coverage of the continental United States (CONUS) are uniformly separated along an equatorial arc around the earth, the GEO satellites are approximately uniformly separated in sine space when viewed from a ground terminal located within CONUS over typical communications frequency bands, such as the Ka band (29-39 GHz) and the Ku band (10-15 GHz). The invention can reduce interference by providing an uniformly illuminated rectangular aperture, in which the horizontal dimension is chosen so when the aperture is normal to a transmission axis between the antenna and the Nth satellite of a SATCOM systems, the nulls of the antenna radiation pattern align with the N±1, N±2, N±3, . . . satellites.

Abstract: A telecommunications satellite channeliser (170) is provided for mapping RF signals between feeder links (160-162) and mobile link beams (210-212) based on a predefined frequency plan (FIGS. 7 and 8). The mobile link beams (240) define a coverage area (242) of a satellite (10). Each feeder link and mobile link beam comprises a plurality of feeder subbands and mobile subbands grouped to form feeder link channels (216-238) and mobile link channels (244-255). The channeliser (170) includes at least one feeder lead carrying a feeder link signal (160-162) associated with a ground station (14 and 16). A feeder link distribution network (175) is connected to the feeder leads and maps RF signals in the feeder links (160-162) onto a plurality of distribution leads as divided feeder signals. Channel multiplexers (182-184) are connected to the distribution leads.

Abstract: A mobile satellite set-top box provides a satellite modem for internet (URL) service, a DBS receiver for TV service, and a GPS receiver for navigational use. The satellite set-top box may be used in mobile or stationary applications such as recreational vehicles, trucks and sea vessels. The set-top box connects to a satellite dish and a GPS antenna for receiving satellite signals. These signals are directed to a motherboard (CPU) in the set-top box which processes user selected outputs such as TV, GPS display or a wireless connection to a personal computer.

Abstract: A satellite communication system which performs multicast switching on data cells. A switch 80 receives the data cells at a set of input ports IP1 and directs those including a multicast routing code to a first set of output ports OP2 or OP128. The switch 80 also directs data cells effectively omitting the multicast routing code to a second set of output ports OP1. One or more multicast replication modules 110, 130 are coupled to the first set of output ports and replicate data cells requiring multicast processing. During the processing, the multicast routing code is effectively omitted and the replicated cells are coupled to input ports IP2 or IP 128 so that the replicated data cells are transmitted to the second set of output ports OP1. An outbound processing module 100 is coupled to output ports OP1 for processing the data cells for transmission over a satellite downlink transmitter 104.

Abstract: A dual-band multiple beam antenna system for a communications satellite sharing a set of reflector antennas for the transmit and receive frequencies. One set of reflectors is common to both the downlink and uplink frequencies. The feed horns are diplexed and exhibit frequency-dependent radiation patterns that separate the phase centers over the downlink and uplink frequency bands to obtain dual-band performance. The focal point of the reflector is in close proximity to the phase center corresponding to the downlink frequency band. The phase center for the uplink frequency band is spaced a predetermined distance from the phase center of the downlink frequency band. According to the present invention, the uplink frequencies are defocused and the downlink frequencies are focused thereby creating identical radiation patterns at both frequency bands and over the coverage region of the communications satellite.

Abstract: A method and apparatus for producing contiguous spot beam communications coverage on the Earth's surface are disclosed. The apparatus comprises two contiguous beam patterns. The first contiguous beam pattern comprises a first set of cells and has a first set of frequencies. The second contiguous beam pattern comprises a second set of cells and has a second set of frequencies. The second contiguous beam pattern is spatially offset from the first contiguous beam pattern such that an edge of the first set of cells is offset from an edge of the second set of cells. Multiple two grid systems can maintain isolation performance of single grid system.