Abstract: A multi-beam satellite has an input section to receive uplink spot beams in a first range of frequencies and an output section to transmit downlink spot beams in a second range of frequencies. An IF section is coupled between the first antenna and second antenna. It down-converts the uplink spot beams in the first range of frequencies to intermediate signals in an intermediate range of frequencies, flexibly and selectively switches and filters the intermediate signals in the intermediate range of frequencies, and up-converts the intermediate signals in the intermediate range of frequencies to the downlink spot beams in the second range of frequencies.

Abstract: In a communication satellite constellation which uses CDMA and multiple spot beams for point-to-point communication, a system is provided for broadcasting regionally related information within a spot beam by establishing a Frequency/Walsh Code Tiling over the Earth's surface, and enabling a user terminal at a given position to tune to an appropriate frequency and Walsh Code to receive the information broadcast from a satellite over a forward beam downlink. The information, e.g. regional messages such as local weather or traffic, is transmitted to the satellite from a ground station or gateway that receives the information from a Broadcast Processing Center. In a preferred embodiment a dedicated Frequency Division Multiplex (FDM) channel within each spot beam transmits the regional broadcast messages at the Tiles in accordance with the Walsh Code designations of the Tiles.

Abstract: A communications satellite method and are provided for controlling a configuration of spot beams produced by a communications satellite. A plurality of spot beams are generated by a communications satellite while maintained at a first orbital position with respect to a first portion of the earth. The plurality of spot beams are configured in a first cell pattern to substantially encompass a first portion of the Earth. The satellite is moved to a second orbital position with respect to a second portion of the earth. Once moved, the satellite is reconfigured such that a second plurality of spot beams form a second pattern 85 to substantially cover the new portion of the earth of interest. A network of switches allows the satellite 10 to be reconfigured for operation from multiple orbital positions. The switching network directs individual feeds to different signal paths having different bandwidth and power capabilities.

Abstract: A demodulator of a W-CDMA base station comprises: a chip calculator for de-spreading signals received through sectors including antennas; a symbol calculator for using symbols of a control channel and a data channel from the de-spread signals, estimating a channel, and combining signals input through a multi-path; a frame calculator for combining the combined signals to perform transport format combination indicator decoding, feedback information decoding, frame sync estimation, SNR estimation, post-combining, and second de-interleaving; a storage unit for storing outputs of the chip calculator, symbol calculator, and frame calculator; a storage unit controller for controlling inputs/outputs between the chip calculator, symbol calculator, frame calculator, and storage unit; and a host interface for controlling inputs/outputs between the chip calculator, symbol calculator, frame calculator, and host.

Abstract: A telecommunications system and method is disclosed for allowing a base station to simultaneously transmit signals in several beams of a multi-beam antenna configuration. Antenna pattern control is maintained by employing orthogonal polarization orientation for every other beam. For example, the two orthogonal polarization directions can be approximately linear polarization slanted ±45°. To be able to transmit simultaneously in an arbitrary combination of more than one beam, the BS antenna array includes a separate feeder cable for each combination of beams corresponding to a particular polarization, from one feeder per beam to one feeder with all beams of that polarization.

Abstract: A satellite communication system having a spatial segment comprising at least one satellite, preferably in a geostationary orbit, carrying a multi-beam telecommunication payload and a terrestrial segment comprising access gateways to terrestrial networks each arranged to communicate with the satellite via a forward link uplink beam and a return link downlink beam and user terminals each arranged to communicate with a satellite via a forward link downlink beam and a return link uplink beam, wherein the forward link carries signals multiplexed in time and the return link carries signals multiplexed in frequency and time, the payload comprising; a forward link router for routing signals multiplexed in time from a forward link uplink beam on a frame basis to a forward downlink beam, a return link router for routing signals multiplexed in frequency and time from a return uplink beam on a frequency bank basis to a return link downlink beam, and a mesh communication router for receiving signals multiplexed in freque

Abstract: An apparatus for reducing the amount of circuitry required to process satellite communication signals uses a beamformer to reduce the number of signals coupled to the communications circuitry, thereby reducing the amount of communication circuitry required to process received signals.

Abstract: A method and computer program to configure feeds on a satellite (300, 310, 320) to provide for redundant coverage when a satellite (300, 310, 320) fails. Further, this method and computer program can enable the switching of feeds from commands from a ground station (30) to activate certain feeds and deactivate other feeds when demand for service changes. In addition, this method and computer program allow for repositioning of satellites so that when one satellite fails another satellite may take over its area of coverage by switching active feeds without the need for placing another satellite in orbit.

Abstract: A system and method for allocating uplink and downlink bandwidth in a communication system is presented. The communication system includes a communication platform, a plurality of spokes and at least one hub. The plurality of spokes and at least one hub communicate through the communication platform. Each spoke includes spoke uplink bandwidth and spoke downlink bandwidth and each hub includes hub uplink bandwidth and hub downlink bandwidth. The allocation of bandwidth among the spokes and hub may be dynamically adjusted based on the present user demands. Additionally, if the communication system is a packet switched system, empty packets may be discarded at the communication platform and the bandwidth that was previously allocated to the packets may be reallocated.

Abstract: A beam control subsystem (200, FIG. 2) provides acquisition, synchronization, and traffic beams (142, FIG. 1) to communication devices (130) within a footprint (144) of a system node (110), where each beam comprises a set of beamlets (140). The subsystem (200, FIG. 2) first acquires (302, FIG. 3) and synchronizes (304, FIG. 3 and FIG. 6) with each communication device. Acquisition involves selecting (402, 416, FIG. 4) and combining (404) sets of beamlets (506, 510, FIG. 5), and determining whether any devices within the sets are attempting to acquire the system. If so, synchronization is performed by varying (604, FIG. 6) beamlet weighting coefficients to find, based on modem feedback, a combination of coefficients that yields a maximum signal-to-interference+noise ratio for multiple users within a beam. The communication device is then handed off (612, 614) to a traffic beam. The subsystem (200) continues, based on modem feedback, to adapt (802, 804, FIG.

Abstract: A method and device for using a single antenna for simultaneously receiving radio frequency signals in a first radio frequency band and radio signals in a second radio frequency band different from the first radio frequency band.

Abstract: A transponder system that integrates redundancy and beam selection capabilities is disclosed. The transponder system comprises an amplifier network having a plurality of amplifiers; an antenna network, comprising a plurality of antennae; an output switching network, including a first output switching network switch, selectably coupling one of the amplifiers to one of the plurality of antennae at a first output switching network switch first switch state and to a second output switching network switch in a first output switch network switch second switch state, wherein the second output switching network switch is selectably coupled to a second one of the plurality of antennae in a second output switching network switch first switch state and to a third one of the plurality of antennae in a second output switching network switch second switch state.

Abstract: First and second waveguides which have respective axes thereof arranged parallel to each other are respectively held by dielectric feeders. A projection wall or a thick wall is formed as a correction part on a front surface of a waterproof cover which covers radiation parts of the dielectric feeders. Due to such a constitution, when radio waves transmitted from neighboring first and second satellites are converged by a reflector and are incident on the inside of respective waveguides, it is possible to delay a phase of radio waves which pass the waterproof cover by the correction part (projection wall or thick wall) so that it is possible to adjust such that radiation patterns of radio waves which are incident on the respective waveguides are reflected on a common portion of the reflector whereby the required reflector can be miniaturized.

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 connection request signal issued from a terminal (PS2) corresponding to a new call and received by an array antenna (2) is supplied to an adaptive array (14) and a parameter estimating unit (15). The parameter estimating unit (15) lowers a send power of a terminal (PS1) corresponding to an existing call by a predetermined level when it is detected from an output of the adaptive array (14) and a signal supplied from the antenna (2) that the connection request signal is received via a C-channel.

Abstract: The present invention provides a method for custom coding uplink signals and downlink beams in a satellite communications system. The method includes the step of applying, at a ground station (100), an outer code (102) to an uplink signal to produce an outer coded uplink signal. Next, the ground station (100) applies a selected reduced complexity inner code (104) to the outer coded uplink signal to produce a concatenated coded uplink signal. The ground station (100) transmits the concatenated coded uplink signal to a satellite (110). At the satellite (110), the inner code of the concatenated coded uplink signal is decoded (116) to produce an outer coded satellite data stream. Next, the satellite (110) applies a selected inner code (120) to a portion of the outer coded satellite data stream to produce a concatenated coded satellite data stream. The satellite (110) then transmits the concatenated coded satellite data stream in a downlink beam to a destination ground station (126).

Abstract: A GSO satellite constellation (10) and an NGSO constellation (20) may be used to send various types of communication signals and multimedia signals to an aircraft (30). The video signals are demodulated by a demodulator (46) and routed by a router (64) to TV monitors (72 and 74), as well as short-term video storage (78). Data can be received and transmitted by a low gain, narrowband transmitter/receiver (100) in order to provide voice, computer and control communications at all times during the flight of aircraft (30).

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: A satellite communication system includes a plurality of spacecraft in geosynchronous orbit, where each spacecraft provides a plurality of beams on the surface of the earth, and a plurality of ground stations individual ones of which are located in one of the beams for transmitting uplink signals to one of the spacecraft. Each spacecraft has a plurality of receivers for receiving a plurality of the uplinked signals from ground stations, a frequency translator for translating the received uplink signals to a transmission frequency of a plurality of downlink signals, and a plurality of transmitters for transmitting the plurality of downlink signals within the same beams as the corresponding uplink signals. In accordance with the invention the beams have at least one of different sizes and shapes, including circular and elliptical, and are non-contiguous over a least a portion of the surface of the earth.

Abstract: A flexible bandwidth satellite communications system, having two communications quartets with at least one controller spot beam per quartet. Each quartet comprises four transponders having multiple type bandwidth filters with controllable pass-bands controlled by a gateway located in an opposite quartet.

Abstract: A satellite communications system (10) provides for snap to grid variable beam size digital beamforming. 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. The beamforming subsystem (40) forms beams based on the processed signals wherein the beams match predetermined grid information. The beamforming subsystem (40) includes a grid database (50) containing predetermined grid information. A beamforming processor (60) converts the predetermined grid information contained in the grid database (50) antenna coefficients. An antenna management system forms beams based on the antenna coefficients.

Abstract: A device having a variable output electrical characteristic includes first and second output terminals and a number of switching circuits, each switching circuit having two states. One of the states produces a first electrical effect (such as an increased resistance) between the first and second output terminals, and the other state produces a second electrical effect (such as no change in resistance) between the first and second output terminals. A processor generates control signals that are applied to the switching circuits to place the switching circuits into a desired state such that the variable output characteristic between the first and second terminals is set to a desired value, which may be input from a user.

Abstract: An improved satellite communication device and system are provided. The satellite communication device uses yaw or roll-yaw steering to linearize angular track of uplink cells; one-dimensional linear “ratcheting” in an uplink antenna to maintain resource allocation of uplink cells along antenna columns; phased-array downlink antennas which can track earth-fixed downlink cells while compensating for the yaw (or roll-yaw) satellite steering; and variable rate TDMA service among downlink cells in a footprint. As a result, system overhead for performing new resource allocations between satellite handovers is minimized, thereby reducing resource management and increasing system capacity. Flexible bandwidth/capacity assignment of both uplink and downlink resources to earth locations via linear cell ratcheting, uplink RF peaking switch, and data-driven variable-TDMA downlink phased-arrays, is provided.

Abstract: A satellite communication system includes at least one spacecraft in geosynchronous orbit for providing a plurality of beams on the surface of the earth, and a plurality of ground stations individual ones of which are located in one of the beams for transmitting uplink signals to the spacecraft. The spacecraft has a plurality of receivers for receiving a plurality of the uplinked signals from ground stations, a frequency translator for translating the received uplink signals to a transmission frequency of a plurality of downlink signals, and a plurality of transmitters for transmitting the plurality of downlink signals within the same beams as the corresponding uplink signals. Each transmitter includes a combiner for combining together a plurality of frequency translated signals and a power amplifier, such as a TWTA, for amplifying the combined plurality of frequency translated signals.

Abstract: Antenna elements 20 are arranged at intervals “d” greater than &lgr;/2, e.g., 5&lgr;. A signal received by an antenna element 20 is sent by way of an antenna multiplexer 21 to a receiver 23, where the signal is demodulated. The thus-demodulated signal is sent to a phase-and-power detection section 25, where a phase and power of the signal are detected. On the basis of the result of such detection, a control section 26 calculates the phase and power of a transmission signal. On the basis of the result of the calculation, a transmission signal generation circuit 27 transmits a transmission signal to each of the antenna elements 20 by way of the antenna multiplexer 21.

Abstract: The invention relates to a geosynchronous satellite including antenna means for communicating with an area (34) of the terrestrial surface.

Abstract: A satellite broadcast system and method, particularly useful for television signals, allows for local as well as nationwide broadcast service by allocating greater satellite resources to the more important local service areas. This is accomplished by broadcasting a non-uniform pattern of local service beams and designing the system to establish different service area priorities through factors such as the individual beam powers, sizes, roll-off characteristics and peak-to-edge power differentials. Frequency reuse is enhanced by permitting a certain degree of cross-beam interference, with lower levels of interference established for the more important service areas.

Abstract: A method and apparatus for providing remote control of the output power level of an amplifier. The method uses pulse width or pulse density modulated signal proportional to the power level of the amplifier. This signal is detected and filtered to provide a control voltage to the apparatus mentioned below. The apparatus includes an amplifier, and a comparator having a first input coupled to an output terminal of the amplifier, a second input coupled to a control signal, and an output terminal coupled to an input terminal of the amplifier. The amplifier and comparator operate to form a feedback loop which functions to equalize the voltage level of an output signal present at the output terminal of the amplifier to the voltage level of the control signal. The equalization of the voltage level of the output signal of the amplifier to the voltage level of the control signal is effected by adjusting the drain current flowing through the amplifier.

Abstract: A communications satellite method and are provided for controlling a configuration of spot beams produced by a communications satellite. A plurality of spot beams are generated by a communications satellite while maintained at a first orbital position with respect to a first portion of the earth. The plurality of spot beams are configured in a first cell pattern to substantially encompass a first portion of the Earth. The satellite is moved to a second orbital position with respect to a second portion of the earth. Once moved, the satellite is reconfigured such that a second plurality of spot beams form a second pattern 85 to substantially cover the new portion of the earth of interest. A network of switches allows the satellite 10 to be reconfigured for operation from multiple orbital positions. The switching network directs individual feeds to different signal paths having different bandwidth and power capabilities.

Abstract: A position-beam correspondence data table in which a plurality of areas on the ground and beams from the communication satellite each covering each area are correlated to each other is previously prepared, a current position of the mobile satellite communication terminal is computed by a position computing means at a point of time when the mobile satellite communication terminal is not executing communications such as when a power for the mobile satellite communication terminal is turned ON, or when a prespecified key is pressed down, a beam corresponding to the computed current position is red out from said position-beam correspondence data table, a beam to be used in the area including the current position is decided, and a beam switch request command for switching to this beam is transmitted to the communication satellite.

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 cellular communications system comprising a space based system comprising a first set of cells, and a ground based system comprising a second set of cells. The space and ground systems can optionally function substantially autonomously, with each using spectrum from at least one predetermined frequency band.

Abstract: A portable telephone comprising an external antenna connector portion 7 for connecting it to an external antenna 2 can detect hook conditions by providing a detecting terminal 73 utilizing a shield portion 72 of the external antenna connector portion 7. In an on-hook condition where the portable telephone is mounted on an on-vehicle adapter 1, corresponding shield portions 72, 73 and 32 of the external antenna connector portions 7 and 3 provided on both the portable telephone and the on-vehicle adapter come into contact with each other. On the other hand, in an off-hook condition where the portable telephone is disengaged from the on-vehicle adapter or the on-vehicle holder, the corresponding shield portions are out of contact from each other. The hook conditions can be thus detected by detecting the change in the contact between the shield portions.

Abstract: An earth station (8) receives a return signal (3) via more than one satellite link (4a, 4b) from a mobile terminal (2) using TDMA. The earth station (8) selects one or more of the satellite links (4a) for transmitting a forward signal (15) on the basis of the quality of signal (3; 15) received via each link. The earth section (8) allocates frequency channels to the mobile terminals (2) according to their location on the surface of the earth, so that the propagation time to and from those mobile terminals (2) which share the same frequency channel is approximately the same. The satellite (4a; 4b) includes an antenna which generates an array of beams which are individually pointed to fixed regions of the earth, until the elevation of the satellite (4a; 4b) relative to a fixed region falls below a minimum value, in which case the corresponding beam is redirected to a new area, while the other beams remain pointed at the corresponding fixed areas.

Abstract: A satellite antenna pointing system has a reflector antenna for receiving an uplink signal from an earth based ground station and a satellite based phased array assembly for transmitting a downlink signal. Because extraterrestrial communications suffer significant losses during transmission, accurate pointing of both uplink and downlink antennas is desired in order to reduce required signal strength. The present invention uses two different methods for pointing the uplink and downlink antennas.

Abstract: An apparatus for forming a beam in a base station is provided and includes a plurality of channel cards for processing and outputting signals to be transmitted to each channel; a signal synthesizer/distributor for synthesizing the signals from the channel cards and compensating phases of the signals; a channel controller for controlling beams of the signals from the signal synthesizer/distributor according to a demand of a mobile communication terminal and outputting the controlled beam signals; a middle frequency generating block for receiving the signals from the channel controller and synthesizing the signals in each frequency to generate middle frequency signals; a transmitter for converting the middle frequency signals received from the middle frequency generating block into signals in a transmitting band; an RFB for amplifying the signals from the transmitter into signals in an output band and controlling phases of transmitting and receiving signals; and an antenna connection block for switching the sig

Abstract: A radio communication system comprises a communication channel between a transmitter having parts operating according to a plurality of radio standards and having a plurality of antennas and a receiver having parts operating according to a corresponding plurality of radio standards having at least one antenna. In such a system the communication channel comprises a plurality of paths having a range of characteristics. Data for transmission is generated by one or more applications and is transmitted using an appropriate radio standard.

Abstract: This invention describes a method to generate large numbers of spot beams for multiple-beam satellite systems using smaller apertures. This is done by dividing the basic spot beam that has 3 to 4 dB of gain drop within the beam into a number of smaller 1-dB sub-beams. This has the effect of reducing the required peak gain for the antenna by 2-3 dB, thus reducing its size by as much as 50%. The frequency band allocated to the basic beam will be divided among the sub-beams. However, the frequency re-use among the basic beams can be maintained. Frequency allocations have to be coordinated among all beams. This concept is especially applicable to phased arrays using digital beam formers. The DBF complexity is a function of the number of array elements, and is less dependent on the number of beams. Reducing the array size, and consequently reducing the number of elements helps in reducing the complexity, power and mass of the DBF.

Abstract: A land mobile-satellite communication system comprises: at least one communication satellite station; a plurality of portable communication terminals for communicating with each other through a communication link to be formed to include the at least one communication satellite station; and a plurality of mobile repeater stations mounted on mobiles located on the earth for repeating the communication in the communication link formed between the portable communication terminals and including the at least one communication satellite station. Preferably, the system includes a plurality of communication satellite stations, each mounted on a respective one of a plurality of low earth communication satellites, and each including a mechanism for communicating each other through inter-satellite links.

Abstract: A dynamic repeater configuration for satellite systems is disclosed that allows for multiple broadcast of channel information and multiple subchannel allocations on uplink and downlink beam signals. The apparatus comprises an input multiplexer, a subchannel routing switch matrix, a channel routing switch matrix, and an output multiplexer. The input multiplexer receives the uplink signal and produces at least a first channel signal therefrom. The subchannel routing switch matrix receives the uplink signal, separates at least one channel signal into at least one subchannel, routes the subchannel from a selected uplink subchannel into a selected downlink subchannel, and recombines the selected downlink subchannels into a second channel signal. The channel routing switch matrix routes the first channel signal into a first downlink channel signal and the second channel signal into a second downlink channel signal. The output multiplexer combines the first and second downlink channels into the downlink signal.

Abstract: A communication station for generating or receiving an angularly dispersed array of radiation beams, comprising an array of radiating elements (100) defining an array antenna (1); and a beam former (120), the beam former comprising a passive network having a first side (X) carrying a plurality of beam ports for electrical signals corresponding to the beams and a second side (Y) carrying a plurality of antenna ports corresponding to the radiating elements, each beam port being connected to a plurality of antenna ports via a network (50) of power divider (52) and phase shifter (53) components, the phase shifts of which are in integer multiples of a predetermined constant, so as to generate the array of beams; in which the array antenna (1) has triangular or hexagonal symmetry and the array of beams has triangular or hexagonal symmetry.

Abstract: A satellite-based communications system operating at high data rates includes a plurality of satellites each having uplink and downlink antennas for transmitting and receiving a plurality of signal utilizing a plurality of spot beams to and from a plurality of coverage areas at a predetermined range of frequencies. The system also includes a plurality of user terminals for transmitting and receiving signals to and from the plurality of communications satellites at the predetermined range of frequencies and at one of the first plurality of data rates. Each of the user terminals having a steerable antenna for tracking relative movement of each of the user terminals with respect to each of the plurality of communications satellites are for tracking movement of each of the plurality of communications satellites in order to maintain communications with the plurality of communications satellite.

Abstract: A satellite-based communications system operating at high data rates includes a plurality of communications satellites each having an uplink and a downlink antenna for receiving and transmitting a plurality of spot beams which may be fixed or scanned. The fixed beams may be directed to areas of high satellite use. The scanned beams may be rapidly scanned between areas of use insufficient to support a dedicated beam. The scanned beam allows potentially nearly ubiquitous coverage by using high frequency beams. To rapidly scan, beam forming networks have a plurality of phase coefficients that may be changed so that the angle of the beam may change. A controller coupled to the beam forming network may be used to change the phase coefficients in response to beam inputs such as the desired beam and configurations of the other beams on the satellite.

Abstract: Receiving apparatus for receiving satellite broadcasting electric wave to be mounted mobile vehicle being realized at low cost and not influence by the weather etc. The apparatus is provided with an antenna of which directivity pattern can be varied, and by a geomagnetism sensor mechanically coupled with said antenna to detect present orientation of the antenna, and comprising antenna controlling means by which the directivity pattern of the antenna is directed towards objective broadcasting satellite based on said detected orientation output. When an electric wave from a gap-filler station is to be received, the antenna is controlled to become non-directivity pattern automatically. For the antenna, a microstrip patch antenna having a plurality of conductive patches arranged in a plane is used.

Abstract: An earth station receives a return signal via more than one satellite link from a mobile terminal using TDMA. The earth station selects one or more of the satellite links for transmitting a forward signal on the basis of the quality of signal received via each link. The earth section allocates frequency channels to the mobile terminals according to their location on the surface of the earth, so that the propagation time to and from those mobile terminals which share the same frequency channel is approximately the same. The satellite includes an antenna which generates an array of beams which are individually pointed to fixed regions of the earth, until the elevation of the satellite relative to a fixed region falls below a minimum value, in which case the corresponding beam is redirected to a new area, while the other beams remain pointed at the corresponding fixed areas. In this way, beam-to-beam handover is reduced, while maintaining the boresight of the antenna pointing at the nadir.

Abstract: A telecommunications satellite channelizer (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 channelizer (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 communications system for determining the position and velocity of an object using a plurality of GPS signals transmitted by a plurality of GPS sources includes an interrogator remote from the object and responsive to the plurality of GPS signals. The interrogator transmitts an RF signal including GPS source information and at least one of frequency information and time and code phase information of at least one of the GPS signals. The system also includes a transponder positioned on the object and responsive to the RF signal and the plurality of GPS signals. The transponder tracks one of the plurality of GPS signals in response to the GPS source information and the frequency information and time and code phase information. The transponder generates a correlation snapshot and transmits the snapshot to the interrogator.

Abstract: An adaptive transceiver architecture which reallocates communications resources in real time based on the amount of bandwidth being used in communications channels in the system. The transceiver receives communications signals from a plurality of communications beam spots. Each communications beam spot has a predefined bandwidth divided into non-overlapping subbands. The transceiver further comprises a plurality of front end signal conditioners for receiving communications signals from an equal plurality of communications beam spots. A predetermined number of the conditioned signals are then combined by an interconnect. The interconnect receives composite signals from the front end signal conditioners, and it combines at least first and second communications signals from first and second respective composite signals to form an output processing signal.

Abstract: A satellite-based communications system operating at high data rates includes a plurality of communications satellites each having an uplink and a downlink antenna for receiving and transmitting a plurality of spot beams which may be fixed or scanned. The fixed beams may be directed to areas of high satellite use. The scanned beams may be rapidly scanned between areas of use insufficient to support a dedicated beam. The scanned beam allows potentially nearly ubiquitous coverage by using high frequency beams. To rapidly scan, beam forming networks have a plurality of phase coefficients that may be changed so that the angle of the beam may change. A controller coupled to the beam forming network may be used to change the phase coefficients in response to beam inputs such as the desired beam and configurations of the other beams on the satellite.

Abstract: A communication satellite transmitting system includes communication signal amplifiers (e.g., traveling wave tube (TWT) amplifiers) with outputs that are multiplexed among multiple transmit horns, each of which transmits a downlink communication signal to a corresponding geographic cells. In one implementation, each TWT amplifier is multiplexed among at least three transmit horns.