Abstract: One embodiment is directed to an aircraft position report system. The system comprises a satellite, an aircraft position reporting receiver mounted on the satellite, an antenna element mounted on the satellite, and an antenna interface mounted on the satellite. The aircraft position reporting receiver receives aircraft position reports through the antenna element by associating a spot beam with a narrow coverage area. The aircraft position reports are derived from a signal produced by the antenna element. The antenna interface changes the narrow coverage area associated with the spot beam to receive aircraft position reports from a wide coverage region within a reporting period. In one exemplary embodiment, the antenna interface mechanically steers the spot beam for each receiver to one of the narrow coverage areas. In another exemplary embodiment, the antenna interface electronically steers the spot beam for each receiver to one of the narrow coverage areas.

Abstract: A method for maintaining a nominal decoder time phase alignment through a data drop-out period is provided. The method includes determining if a search window is open. A search-window width of the search window is an initial search-window width. The initial search-window width is larger than the width of the frame synchronization pattern. The method also includes determining if a bit clock rising edge is detected and searching for the frame synchronization pattern on a bit level when the search window is open and the bit clock rising edge is detected. If the frame synchronization pattern is not found responsive to the searching, the method also includes determining if a receipt time of the bit received when the bit clock rising edge was detected is coincident with an expected start time of the frame synchronization pattern.

Abstract: A method for maintaining a nominal decoder time phase alignment through a data drop-out period is provided. The method includes determining if a search window is open. A search-window width of the search window is an initial search-window width. The initial search-window width is larger than the width of the frame synchronization pattern. The method also includes determining if a bit clock rising edge is detected and searching for the frame synchronization pattern on a bit level when the search window is open and the bit clock rising edge is detected. If the frame synchronization pattern is not found responsive to the searching, the method also includes determining if a receipt time of the bit received when the bit clock rising edge was detected is coincident with an expected start time of the frame synchronization pattern.

Abstract: A system comprises an outer shell having an inner spherical cavity and an inner sphere located in the spherical cavity. The inner sphere comprises a sensor; at least one transmit antenna; and at least one transmitter coupled to the sensor and to a respective one of the at least one transmit antenna. The system also comprises a first receive antenna located in the spherical cavity; a second receive antenna located in the spherical cavity; and a receiver located outside of the outer shell. The receiver is configured to determine the signal to noise ratio of a first signal received at the first receive antenna and the signal to noise ratio of a second signal received at the second receive antenna; and to combine the first and second signals based on the respective signal to noise ratios such that interference due to multi-path signals in the spherical cavity is reduced.

Abstract: A method for synchronizing frames when a frame synchronization pattern is lost is provided. The method includes forcing a frame state machine to an operate mode following an initial synchronization, searching for the frame synchronization pattern on a bit level while running the frame state machine in the operate mode, and correcting for synchronization on the bit level while running the frame state machine in the operate mode when synchronization is lost. The initial synchronization includes a search mode.

Abstract: One embodiment is directed to an aircraft position report system. The system comprises a satellite, an aircraft position reporting receiver mounted on the satellite, an antenna element mounted on the satellite, and an antenna interface mounted on the satellite. The aircraft position reporting receiver receives aircraft position reports through the antenna element by associating a spot beam with a narrow coverage area. The aircraft position reports are derived from a signal produced by the antenna element. The antenna interface changes the narrow coverage area associated with the spot beam to receive aircraft position reports from a wide coverage region within a reporting period. In one exemplary embodiment, the antenna interface mechanically steers the spot beam for each receiver to one of the narrow coverage areas. In another exemplary embodiment, the antenna interface electronically steers the spot beam for each receiver to one of the narrow coverage areas.

Abstract: A method for synchronizing frames when a frame synchronization pattern is lost is provided. The method includes forcing a frame state machine to an operate mode following an initial synchronization, searching for the frame synchronization pattern on a bit level while running the frame state machine in the operate mode, and correcting for synchronization on the bit level while running the frame state machine in the operate mode when synchronization is lost. The initial synchronization includes a search mode.

Abstract: A system comprises an outer shell having an inner spherical cavity and an inner sphere located in the spherical cavity. The inner sphere comprises a sensor; at least one transmit antenna; and at least one transmitter coupled to the sensor and to a respective one of the at least one transmit antenna. The system also comprises a first receive antenna located in the spherical cavity; a second receive antenna located in the spherical cavity; and a receiver located outside of the outer shell. The receiver is configured to determine the signal to noise ratio of a first signal received at the first receive antenna and the signal to noise ratio of a second signal received at the second receive antenna; and to combine the first and second signals based on the respective signal to noise ratios such that interference due to multi-path signals in the spherical cavity is reduced.

Abstract: A system comprises an outer shell having an inner spherical cavity and an inner sphere located in the spherical cavity. The inner sphere comprises a sensor; at least three transmit antennas; and at least three transmitters each coupled to the sensor and to a respective one of the at least three transmit antennas. The system comprises at least three receive antennas each located in the spherical cavity, wherein each of the at least three receive antennas is frequency matched to a transmit frequency of a respective one of the at least one transmit antennas. The system also comprises at least three receivers each coupled to a respective one of the at least three receive antennas and a data selection logic circuit configured to select at least one signal from the signals received from each of the at least three receivers based on the respective signal quality of the received signals.

Abstract: A system for receiving an optical communication signal includes a first array of light responsive devices defining a first target area and a second light responsive device defining a second target area. The second target area is smaller than the first target area. A detection device is coupled to the first array of light responsive devices and configured to identify at least one individual light responsive device in the first array of light responsive devices receiving the greatest light input relative to other light responsive devices in the first array of light responsive devices. A positioning device is configured to position the second light responsive device relative to the at least one individual light responsive device, such that the second light responsive device receives the optical communication signal.