Abstract: A user terminal and a method of using the user terminal disclosed. The method may comprise: storing, at a user terminal (UT), a dataset that comprises a plurality of elements, wherein each of the plurality of elements is associated with a unique predetermined terrestrial location; using the dataset, determining an element (Ek) from among the plurality of elements based on a proximity of the UT to the respective unique, predetermined terrestrial location of the element (Ek); and then determining one of the plurality of satellite beams with which to utilize satellite communication.

Abstract: A user terminal and a method of using the user terminal disclosed. The method may comprise: storing, at a user terminal (UT), a dataset that comprises a plurality of elements, wherein each of the plurality of elements is associated with a unique predetermined terrestrial location; using the dataset, determining an element (Ek) from among the plurality of elements based on a proximity of the UT to the respective unique, predetermined terrestrial location of the element (Ek); and then determining one of the plurality of satellite beams with which to utilize satellite communication.

Abstract: A computer comprises a processor programmed to identify a plurality of sets of channels. Each set of channels includes first, second and third channels. The first and second channels in each set include uplinks respectively in first and second neighbor beams and have a first bandwidth overlap. The first and third channels in each set share a target and a third downlink included in the third channel has a second bandwidth overlap with a first downlink included in the first channel. the second bandwidth overlap includes a bandwidth corresponding to at least a portion the first bandwidth overlap, such that a signal spectrum in the first bandwidth overlap is included in the second bandwidth overlap. The computer is further programmed to optimize a bandwidth reduction across the plurality of sets of channels.

Abstract: A computer comprises a processor programmed to identify a plurality of sets of channels. Each set of channels includes first, second and third channels. The first and second channels in each set include uplinks respectively in first and second neighbor beams and have a first bandwidth overlap. The first and third channels in each set share a target and a third downlink included in the third channel has a second bandwidth overlap with a first downlink included in the first channel. the second bandwidth overlap includes a bandwidth corresponding to at least a portion the first bandwidth overlap, such that a signal spectrum in the first bandwidth overlap is included in the second bandwidth overlap. The computer is further programmed to optimize a bandwidth reduction across the plurality of sets of channels.

Abstract: An apparatus for defining and generating boundaries of satellite coverage. The apparatus includes a processor that is configured to select a plurality of beam points, from a set of points on a coordinate system, to be included within a beam definition, and determine a number of ellipses capable of enclosing the selected beam points while excluding all remaining points of the set of points. The processor then assigns the selected beam points to a corresponding ellipse, and optimizes geometric information for each ellipse to enclose the beam points assigned thereto. A coverage beam is then defined based on a contour resulting from the combined shape of all the ellipses using the optimized geometric information.

Abstract: An apparatus for defining and generating boundaries of satellite coverage. The apparatus includes a processor that is configured to select a plurality of beam points, from a set of points on a coordinate system, to be included within a beam definition, and determine a number of ellipses capable of enclosing the selected beam points while excluding all remaining points of the set of points. The processor then assigns the selected beam points to a corresponding ellipse, and optimizes geometric information for each ellipse to enclose the beam points assigned thereto. A coverage beam is then defined based on a contour resulting from the combined shape of all the ellipses using the optimized geometric information.

Abstract: A triple use satellite system includes a VSAT population including a VSAT, and a satellite including a broadcast beam for a broadcast service and spot beams for a broadband service, where each of the spot beams provides broadband service to VSATs in separate coverage areas in a geographic region and the broadcast beam provides a broadcast service to the VSAT population in the geographic region.

Abstract: A high capacity satellite communications system including a satellite with a beam for a forward downlink focused on a geographic area for which disproportionately higher capacity is desired, a hub located in a geographic area for which disproportionately lower capacity is desired, compared to the location of a VSAT, and the VSAT located in area where a beam for a forward downlink received by the VSAT from the satellite does not overlap with a beam for a return downlink received by the hub from a satellite.

Abstract: A triple use satellite system includes a VSAT population including a VSAT, and a satellite including a broadcast beam for a broadcast service and spot beams for a broadband service, where each of the spot beams provides broadband service to VSATs in separate coverage areas in a geographic region and the broadcast beam provides a broadcast service to the VSAT population in the geographic region.

Abstract: An apparatus for positioning a directional antenna of a remote ground terminal which transmits and receives signals to and from a satellite via the antenna. The apparatus includes a signal generator for producing a frequency variable reference signal having a variable duty cycle, and a controller which operates to analyze the signals received from the satellite and to vary the duty cycle of the reference signal in accordance with an identification tag forming part of the received signals. The apparatus further includes a detector which receives the reference signal and produces an antenna pointing signal having an average amplitude proportional to the duty cycle of the reference signal.

Abstract: The effects of long-term drift in a local reference oscillator are compensated by dividing the local reference oscillator frequency by one of three divider patterns (nominal ratio, add a cycle, delete a cycle) so that the symbol clock of the remote terminal is equal to the outroute symbol rate. The number of add a cycle and delete a cycle divider patterns are counted and stored. The average of the number of add a cycle and delete a cycle patterns is used to control the transmit frequency of the remote terminal to correspond to the outroute symbol rate. Thus, the clock recovery process generates a frequency calibration number used to track the frequency of the remote terminal local reference oscillator and to adjust the transmit frequency of the remote terminal accordingly.

Abstract: The frequency and power of transmissions in a mobile communication system, such as an air-to-ground telephony system, are stabilized without a priori knowledge of the system gain factors or frequency references. The ground station monitors the available channels and modifies a vacant channel broadcast message to provide information that the channel is available. In this way, the air terminals have knowledge of all available channels. The ground station transmits a pilot signal. Upon request by a user for a dial tone at the air terminal, the air terminal selects a vacant channel and scans for the pilot signal. The air terminal estimates a distance to the ground station and sets a power level of a seizing transmission based on the estimated distance. The air terminal also estimates a Doppler frequency shift of the selected channel due to the relative movement of the air terminal with respect to the ground station and sets a frequency of the seizing transmission based on the estimated Doppler frequency shift.

Abstract: A TDMA system operates without the requirement for a reference burst. A station in the TDMA system monitors the bursts from other stations to determine the virtual reference. The virtual reference is then used as the basis, at the station, for transmitting its own burst. For carrier-based TDMA systems, the station can also determine a virtual carrier reference. This is implemented by measuring the received carrier from a plurality of bursts. The received carrier frequency of all of the bursts that have been received can then be averaged, and after correcting for frequency translation introduced by the transponder, the result can be employed as a virtual carrier reference.

Abstract: A collision detection mechanism includes a transmission protocol which locates a gap in a station's transmission, of fixed duration and position, relative to start of transmission. Collision detection is enhanced since random timing of collisions normally results in filling in the gap. This condition is more readily detectable than detecting the simultaneous presence of energy from two transmitters. The transmission protocol is followed unless the transmitting station detects a collision, in which event gap creation is inhibited. The gap detecting equipment may be located at a network head end.