Abstract: A follower aircraft is guided to a lead aircraft using a datalink that determines range between the two. The lead aircraft has an antenna array and processing system for determining azimuth/elevation of the follower aircraft. The lead aircraft transmits a ranging message to the follower aircraft and stores a lead aircraft time of transmit (TOT) time. The ranging message is received at the follower aircraft and a follower aircraft time of reception (TOR) time is stored. A second ranging message is transmitted from the follower aircraft to the lead aircraft and a follower aircraft TOT time is stored. The second ranging message is received at the lead aircraft and a lead aircraft TOR is stored. A message is sent from the follower aircraft when follower aircraft TOT and TOR. The range and time offset is determined by the lead aircraft using follower aircraft TOT/TOR and stored lead aircraft TOT/TOR.

Abstract: A method for transmitting data from a transmitter to a receiver in an ad hoc large scale directional network includes the followings steps. A first training sequence is sent by a transmitter in an ad hoc directional network. The first training sequence is received by a receiver in the ad hoc directional network. The receiver determines a first apparent direction from which the first training sequence is sent. The receiver sends a second training sequence to the transmitter. The transmitter determines a second apparent direction from which the second training sequence is sent. The transmitter directs a signal with the first training sequence to the receiver. The transmitter sends the signal with the first training sequence to the receiver. The receiver receives the first training sequence. The receiver is directed to the first apparent direction to receive the signal.

Abstract: Information packets are error encoded for transmission through a communication channel (34) in a communication system (10) using a variable payload outer code and a common physical layer inner code. The variable payload outer code is selected for each packet based upon an application or service associated with the packet. Thus, less coding can be used for packets associated with error tolerant applications and more coding can be used for packets associated with error sensitive applications. A common header outer code is also used for the packets. The variable payload outer code is preferably applied at the system adaptation level within an interworking function (22, 24) in the communication system (10). The common header outer code and the common physical layer inner code are preferably applied at the data link layer.

Abstract: A central controller (40) executes a method (100) that selects and assigns channels to serve mobile subscriber units (30) in a space-based mobile telecommunication system (10). The method (100) is based on simultaneous consideration of a number of criteria that affect overall system performance of the mobile telecommunication system. Another method (200) assigns serving cells (15-18) by matching the available channel resources with actual caller demand as a function of time. The methods (100, 200) may be used in systems where the actual demand (i.e., offered subscriber traffic) and the number of channels available in each cell (15-18) is varying over time.

Abstract: In a satellite cellular communication system, subscriber traffic is shared between satellites whose antenna coverage patterns overlap during some portion of their orbit. When the power consumption of one satellite exceeds a predetermined level, subscriber units are transferred to cells of a second satellite whose antenna coverage pattern overlaps that of the first satellite. After the subscriber units are transferred, channel assignments are redone to prevent interference with subscriber units in other cells.

Abstract: A system for facilitating global cellular/trunked mobile communication is disclosed. This system permits communication with hand held and mobile mounted cellular telephones. The system permits two-way communications anywhere on or above the earth up to a particular height above the earth of several hundred nautical miles. The system employs a number of low-earth orbiting satellites moving about the earth in orbit. Links are provided from the satellites directly to the users and via the public switched telephone network to other users. The satellites are interconnected via links in a ring structure surrounding the earth. Switching is performed by each of the satellites. In addition, each of the satellites hands off a call as it moves out of the range of a particular user.

Abstract: A method and apparatus for controlling communication channel access in a communication system (10) determines channel allocations (106) which represent limits on communication channel access and conforms operations of the system (10) to the channel allocations. The channel allocations are determined by dividing a surface which emanates signals from communication units (26) into elemental areas, collecting past traffic data (102) describing past communication channel usage by the communication units (26) located in the elemental areas, generating a traffic model (104) for a future time interval based on the past traffic data, and determining the channel allocations (106) based on the traffic model.

Abstract: In a system that includes a constellation of satellite communication nodes, information packets are routed through the constellation using routing tables stored in each communication node. When a packet is received at a node, the packet's destination and routing table ID are read. One of several routing tables are selected using a mapping table. Each of the several routing tables has a different routing instruction set. The packet is routed away from the node using the selected routing table. When system traffic is heavy, or some of the communication links are overloaded or have failed, routing table control bits are sent to the nodes updating the mapping table. Packets are subsequently routed using different sets of routing tables, such as ones having greater hop counts.

Abstract: A system for facilitating global cellular/trunked mobile communication is disclosed. This system permits communication with hand held and mobile mounted cellular telephones. The system permits two-way communications anywhere on or above the earth up to a particular height above the earth of several hundred nautical miles. The system employs a number of low-earth orbiting satellites moving about the earth in orbit. Links are provided from the satellites directly to the users and via the public switched telephone network to other users. The satellites are interconnected via links in a ring structure surrounding the earth. Switching is performed by each of the satellites. In addition, each of the satellites hands off a call as it moves out of the range of a particular user.

Abstract: Orbiting satellites (12) project footprints (30) on the earth. Each footprint (30) is divided into cells (28). Footprints (30) of nearby satellites (12) overlap one another, and the overlap increases as satellites (12) approach a pole from the equator. Positions of all cells (28) generated by all satellites (12) are simulated (36) at numerous points throughout an orbit. Channel sets are assigned to cells (28) within a reference footprint (30a). This assignment is propagated throughout all footprints (30) except for those footprints (30) residing adjacent one side of a seam (16) between orbits (14) where satellites (12) travel in opposing directions. The channel sets are assigned near the seam (16) in response to previously assigned channel sets. Each satellite (12) stores channel set assignments for its cells (28) at various points throughout its orbit. All satellites (12) switch their communication parameters simultaneously in response to the channel set assignments.

Abstract: A power management system for a worldwide multiple satellite system having satellites positioned latitudinally in a polar orbiting constellation, each satellite having a plurality of antenna beams, each beam having a given area of coverage or "cell," the total sum of the cells for each satellite forming a larger coverage for the entire satellite, the satellites each comprising solar cells and batteries wherein the energy within the batteries is generated by the solar cells and must be efficiently managed. The system comprises an earth based control station which programs each of the satellites within the constellation to supply power to the antenna beams of each satellite at predetermined times to avoid overlapping coverage. Each satellite comprises a voltage regulated linear power amplifier to supply only the power needed for the demand within each of the antenna's cells.

Abstract: Orbiting satellites project footprints on the earth. Each footprint is divided into cells. Footprints of nearby satellites overlap one another, and the overlap increases as satellites approach a pole from the equator. The positions of all cells generated by all satellites are simulated at numerous points throughout an orbit. Cells are marked as being active or inactive to compensate for the overlap at each simulated point. Channel sets are assigned to cells within a reference footprint, and this assignment is propagated throughout all footprints in the referenced footprint's orbit. The channel set sequences are propagated to other orbits after taking into account inactive cells located near boundaries between the orbits. Each satellite stores channel set assignments for its cells at the various points throughout its orbit. All satellites switch their communication parameters at the same instant in response to the channel set assignments.

Abstract: There is provided a method and means for controlling the amount of overlap and gaps in coverage of antenna pattern cells of a moving satellite communication system, by determining the relative spatial location of overlapping or gaping cells of converging or diverging satellites as a function of time; determining a point where antenna coverage of one or more cells from a first moving satellite will overlap or gap one or more cells from a second satellite; and turning off or on one or more of the overlapping or gaping cells so as to eliminate interference therebetween without leaving substantial coverage gaps between adjacent antenna patterns.

Abstract: A Telemetry, Tracking and Control (TT&C) system for a satellite cellular communication system utilizing one of the user voice/data communication channels to communicate TT&C data with a satellite and through one satellite to other satellites. A Global Positioning Receiver (GPS) on board each satellite provides position control signals to the on board satellite control subsystem and the GPS receiver communicates ephemeris information to a ground station through the cellular user data channel. The system allows for constant TT&C communication to and from a mobile ground station and to and from any satellite.

Abstract: A method of predicting cell-to-cell hand-offs of mobile subscribers for a satellite cellular communications system. Each satellite of a constellation projects a number of beams or cells upon the earth for communication with mobile subscribers. The satellite transfers (hand-offs) communications links from cell to cell as the satellite moves over the mobile subscriber. Since the movement of the satellite is stabilized in three directions, the projection of the beams or cells follows a predictable path across the face of the earth. Each satellite moves across the earth in one direction. Once a subscriber is located within one cell, the next cell to which the mobile subscriber is handed-off may be determined from the geographic position. For mobile users which are close to boundaries between cells, additional position location may be determined by the calculation of bit error rates.

Abstract: A multiple beam space antenna system for facilitating communications between a satellite switch and a plurality of earth-based stations is shown. The antenna is deployed after the satellite is in orbit by inflation of a raft-type supporting structure which contains a number of antenna horns. These antenna horns are oriented in substantially concentric circular groups about a centrally located antenna horn. Each of the antenna beams projects an area on the earth. Each of the areas of the beams are contiguous. As a result, one large area is subdivided into many smaller areas to facilitate communications. In addition, a lens may be employed to focus the beams of the horn antennas.

Abstract: A method and apparatus for suppressing carrier leakage components in a system for modulating a carrier with a selected signal wherein the carrier and a quadrature component of the carrier are weighted and summed with the modulated carrier to produce a component substantially equal and opposite in phase to the leakage component so that the summing substantially cancels or suppresses the leakage component.