 Method and apparatus for providing instant messaging in a wireless communication system |
| OF THE DRAWINGS Referring to FIG. 1, an apparatus 20 for providing Instant Messaging (IM) in a ... |
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| Method for terminating a wireless communication of a mobile communication unit |
| According to an aspect of the present invention, the foregoing needs are addressed by a method for ... |
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| Rules based methods and apparatus |
| In a principle aspect, the present invention takes the form of a rules-based system for monitoring ... |
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| Wireless data communications using FIFO for synchronization memory |
| A wireless network 100 (FIG. 1) includes a plurality of wireless devices 102-1, 102-2 . . . 102-i .... |
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| Wireless device having context-based operational behavior |
| OF THE PREFERRED EMBODIMENT In accordance with the invention, a wireless device uses profiles that ... |
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| System and method for wireless data exchange between an appliance and a handheld device |
| One aspect of the present invention relates to a wireless data exchange system. The wireless data ... |
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| Remote data acquisition and communication system |
| The invention comprises a remote data acquisition and communication system that includes a ... |
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| Method and system for reading intelligent utility meters |
| What is claimed: 1. A system for communicating with a plurality of utility meters, comprising: ... |
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| Circuit configuration for metering pulse recognition |
| It is accordingly an object of the invention to provide a circuit configuration for metering pulse ... |
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Antenna beam congruency system for spacecraft cellular communications system
| Details |
Inventors: Kent, Edward Jay; Profera, Jr., Charles Edward; Hawkes, Thaddeus Arthur;
Assignee: Lockheed Martin Corp. (Sunnyvale, CA)
Primary Examiner: Patel; Ajit
Assistant Examiner: Phunkulh; Bob A
Attorney, Agent or Firm: Meise; W.H., Kennedy; R.P.
A spacecraft-based cellular communications system includes a spacecraft with transmit and receive antennas, each of which produces a plurality of spot beams which, together, provide coverage of the region served. In order to control the pointing of the spacecraft antennas, four mutually adjacent spot beams are centered over a particular "beacon" location, so that the beacon location lies between a pair of North and South spot beams, and between a pair of East and West spot beams. The transmit antenna is controlled by transmitting a beacon signal in time sequence over each of the four spot beams surrounding the beacon location, and decoding or desequencing the time-sequential signal received at the beacon location. The decoded signal is processed to provide a signal indicating the pointing error of the transmit antenna, and the error signal is used to control a gimbal which controls the pointing of the transmit antenna. The receive antenna is independently controlled by a generally similar system, in which the beacon signal is transmitted from the beacon location to the receive antenna, and the beacon signal is selectively received from the four spot beams in a time-sequential manner. The received beacon signal is processed in much the same manner as in the transmit antenna controller, and controls a gimbal associated with the receive antenna, to cause the receive antenna to point at the beacon location. Since both transmit and receive antennas point at the beacon location, their beams can be congruent. |
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DETAILED DESCRIPTION A spacecraft cellular communication system according to an aspect of the invention includes a spacecraft body.
A signal receiving and frequency conversion arrangement is mounted on the body, for receiving signals from terrestrial stations, and for converting signals received from terrestrial stations at specific frequencies within a first frequency band to other frequencies in a second frequency band.
The first and second frequency bands may be mutually exclusive.
At least one transmit antenna is supported by the spacecraft body.
The transmit antenna includes an array of radiating elements and a first plurality of signal input ports coupled to the radiating elements of the array of radiating elements.
The transmit antenna may be arranged so that signals applied to a signal input port of the transmit antenna causes radiation from one of the transmit antenna elements.
A beamforming network is mounted on the spacecraft body.
The beamforming network includes plural input ports, which are coupled to the receiving and frequency conversion arrangement, and it also includes a plurality of output ports coupled to the signal input ports of the transmit antenna array.
The beamforming network receives, at its plural input ports, signals at the other frequencies within the second frequency band, and combines the signals at the other frequencies in a manner which, in combination with the transmit antenna, generates a plurality of spot radiation beams directed toward the Earth's surface.
The spot radiation beams define overlapping footprints.
The combination of the receiving and frequency conversion arrangement, the beamforming network, and the transmit antenna transmits signals at the other frequencies from the spacecraft to terrestrial user terminals located within the footprints.
The communication system includes a fixed terrestrial terminal lying within the overlap region between at least first and second specific ones of the spot beams, for transmitting signals to the spacecraft at some of the specific frequencies within the first frequency range, for transmission of information signals to at least some of the terrestrial user terminals, as a result of which transmit antenna positional errors may cause the spot beams to be misdirected
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Cell Phones 
