Abstract: A mobile wireless communications system including a plurality of individual transponding nodes of various types, all in communication with a central processing hub. A local user signal is processed by the central processing hub and radiated through multiple paths to a plurality of the plurality of individual transponding platforms simultaneously. The signal is then re-radiated by each of the plurality of the plurality of individual transponding platforms to a mobile terminal that receives the re-radiated signal from the plurality of the plurality of individual transponding platforms coherently and in phase. The number of transponders and codes used to transmit each user signal can be readily adapted to user requirements.

Abstract: A mobile wireless communications system including a plurality of individual transponding nodes of various types, all in communication with a central processing hub. A local user signal is processed by the central processing hub and radiated through multiple paths to a plurality of the plurality of individual transponding platforms simultaneously. The signal is then re-radiated by each of the plurality of the plurality of individual transponding platforms to a mobile terminal that receives the re-radiated signal from the plurality of the plurality of individual transponding platforms coherently and in phase. The number of transponders and codes used to transmit each user signal can be readily adapted to user requirements. Additionally, each user is assigned a profit value by the central processing hub depending upon certain user characteristics. The assigned user profit value allows the total system utility/profitability to be maximized.

Abstract: A method and system for maximizing satellite coverage at predetermined local times for a set of predetermined geographic location includes a processor operative to determine a period of rotation for each of the desired satellites in the satellite constellation. The processor also determines a time dependent coverage of the satellite constellation based on the period of rotation and the trajectory of each of the desired satellites. The trajectories of the desired satellites are tilted until the satellite constellation provides maximum coverage at the predetermined local times for the set of predetermined geographic locations. If a new satellite constellation is being designed, command signals are programmed into a computer of a launch vehicle containing the modified trajectory. If an existing satellite constellation is being modified, the ground station transmits command signals to the satellites for modifying the trajectory of the satellites in accordance with the tilted trajectory.

Abstract: A mobile wireless communications system including a plurality of individual transponding platforms all in communication with a central processing hub. A signal processed by the central processing hub is radiated simultaneously through multiple paths to a plurality of the individual transponding platforms. The signal transmitted to each transponding platform by the hub is appropriately delayed by the hub so as to equalize the differential delay of all such signals from a given receiver location. The radiated signal is then re-radiated by each of the plurality of individual transponding platforms to a mobile satellite terminal that receives the re-radiated signal from the plurality of individual transponding platforms. The signals from the plurality of transponding platforms are all received coherently by the intended user, and incoherently by all other users.

Abstract: A mobile satellite payload 18 and a method for sampling communication signals 26 are provided. The mobile satellite payload 18 uses a plurality of receive radiating elements 24 within a phase array antenna 22 to convert the communication signals 26 to received signals [S(t)]. A plurality of low noise amplifiers (LNAs) 28 amplify the received signals [S(t)] to then be received by a plurality of analog-to-digital (A/D) converters 29. The A/D converters 29 transform the received signals [S(t)] into digital baseband signals [S?(t)].

Abstract: A wireless communication system includes a satellite constellation consisting of a plurality of satellites. Each of the plurality of satellites is in an orbit whose eccentricity and inclination are perturbed relative to the same geosynchronous orbit. Each of the satellites in the constellation is capable of relaying signals in either direction between a central ground hub and a plurality of mobile user terminals. The plurality of satellites are configured such that the period of their geosynchronous orbit remains substantially constant at one sidereal day.

Abstract: A novel method and apparatus is described for reducing the number of CDMA codes for a constellation of multiple trasponder platforms serving a number of subscribers in the same service area. A coherent processing technique synchronizes the phase of CDMA signals arriving at a subscriber from multiple trasponder platforms to increase the code capacity and thus the number of possible subscribers for most of the multiple transponder platform systems in current use.

Abstract: A system and method for tracking a user. The system is adapted for use in a wireless communication system and creates a plurality of beams within a coverage area. A first beam is directed at a user in a first microcell and a number of additional beams illuminate microcells immediately adjacent the first microcell. The system is equipped with a mechanism for detecting movement of the user from the first microcell to one of the immediately adjacent microcells. On the detection of movement of the user, the system redirects the first beam from the first microcell to a second microcell, the second microcell being one of the adjacent microcells. In the illustrative embodiment, the system is implemented in a stratospheric platform based communication system including a hub adapted to communicate with a stratospheric platform. A transceiver and a phased array antenna are disposed on the platform to communicate with the hub and with the user. A second antenna is provided on the platform to communicate with the hub.

Abstract: A mobile wireless communications system including a plurality of individual transponding nodes of various types, all in communication with a central processing hub. A local user signal is processed by the central processing hub and radiated through multiple paths to a plurality of the plurality of individual transponding platforms simultaneously. The signal is then re-radiated by each of the plurality of the plurality of individual transponding platforms to a mobile terminal that receives the re-radiated signal from the plurality of the plurality of individual transponding platforms coherently and in phase. The number of transponders and codes used to transmit each user signal can be readily adapted to user requirements.

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: Methods for increasing the efficiency of satellite constellation operations are disclosed. The steps of the present invention comprise calculating the maximum number of communications signals that each satellite in the satellite constellation can generate, determining an operational constraint on each satellite, the operational constraint limiting the number of communications signals that each satellite can radiate substantially simultaneously, determining an operational space for each satellite wherein the operational space is defined using the operational constraint and the calculated number of signals, and using the operational space for each satellite in the constellation to determine the operational point for the constellation.

Abstract: A modular mobile terminal for a satellite system is disclosed in which the satellite system has a ground station and a network such as a telephone network coupled to the ground station. Each of the mobile terminals has a radome layer and a support layer having a plurality of circuit traces formed thereon. An element module is coupled between the support layer and the radome layer. Each element module comprises a housing and a radiating patch having a feed therethrough. A dielectric layer is coupled adjacent to the radiating patch. A ground plane is disposed adjacent to the dielectric layer on the opposite side of the dielectric layer as the radiating patch. A plurality of circuit chips is coupled to the ground plane. The support layer of the array has a plurality of circuit traces formed thereon. A plurality of interconnections between the circuit chips and the plurality of traces connect the traces and the circuit chips.

Abstract: A method and system for using two-way ranging navigation to accurately determine the location of a transponder platform above-Earth or a fixed or mobile target on the ground or on water. The two-way ranging navigation measurements are used as calibration references, thereby improving the positioning accuracy of GPS. The system includes GPS and a two-way ranging navigation system for taking position measurements of a target. A correction factor is determined as a function of the measurements and the GPS position is adjusted by the correction factor. The method for calibrating GPS using two-way ranging navigation involves taking a two-way ranging navigation measurement and a GPS measurement of a target, determining a correction factor as a function of the measurements, and correcting the GPS position by taking a second GPS measurement and adjusting it by the correction factor.

Abstract: A satellite communication system has a first deployment of a plurality of satellites deployed in a medium earth orbit and two later deployments of a plurality of satellites deployed in the medium earth orbit. The first deployment is spaced so that the second deployment may be easily deployed and interleaved into the first deployment. A ground terminal is used for communicating with the satellites in the first and second deployments.

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 mobile wireless communications system including a plurality of individual transponding nodes of various types, all in communication with a central processing hub. A local user signal is processed by the central processing hub and radiated through multiple paths to a plurality of the plurality of individual transponding platforms simultaneously. The signal is then re-radiated by each of the plurality of the plurality of individual transponding platforms to a mobile terminal that receives the re-radiated signal from the plurality of the plurality of individual transponding platforms coherently and in phase. The central hub synchronizes both the signals received and transmitted from each user through one or more of the transponding nodes. This synchronization is such that the relative arrival time of the PN encoded data in the user signals is synchronized to within a fraction of a chip in both the forward and return links.

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 satellite communication system has a first deployment of a plurality of satellites deployed in a medium earth orbit and two later deployments of a plurality of satellites deployed in the medium earth orbit. The first deployment is, spaced so that the second deployment may be easily deployed and interleaved into the first deployment. A ground terminal is used for communicating with the satellites in the first and second deployments.

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 method and system for using two-way ranging navigation to accurately determine the location of a transponder platform above-Earth or a fixed or mobile target on the ground or on water. The two-way ranging navigation measurements are used as calibration references, thereby improving the positioning accuracy of GPS. The system includes GPS and a two-way ranging navigation system for taking position measurements of a target. A correction factor is determined as a function of the measurements and the GPS position is adjusted by the correction factor. The method for calibrating GPS using two-way ranging navigation involves taking a two-way ranging navigation measurement and a GPS measurement of a target, determining a correction factor as a function of the measurements, and correcting the GPS position by taking a second GPS measurement and adjusting it by the correction factor.