Satellite with omnidirectional coverage
First Claim
1. A method of transmitting signals to a satellite having at least two antennas whose radiation patterns overlap, at least in part, and means for receiving the signals, the method comprising the following steps:
- transmitting the signals as spread spectrum modulated signals;
receiving the signals via the at least two antennas;
summing the signals received via the at least two antennas and delaying at least one of the signals received via the at least two antennas so that a path difference between the summed signals is at least one chip of the spread spectrum modulation; and
demodulating the summed signals.
1 Assignment
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Accused Products
Abstract
The invention concerns a satellite having at least two antennas (3, 5) whose radiation patterns overlap, at least in part and means (45; 47, 49, 51) for receiving the sum of the signals from the various antennas. To limit multipath problems when summing signals from the antennas, the invention proposes that the receiver means include means for demodulating a spread spectrum signal and that the absolute difference between the respective transmission times of signals transmitted to the receiver means via two antennas is greater than one chip of the spread spectrum modulation. Application to a satellite TTC (telemetry, tracking and command) link.
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Citations
16 Claims
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1. A method of transmitting signals to a satellite having at least two antennas whose radiation patterns overlap, at least in part, and means for receiving the signals, the method comprising the following steps:
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transmitting the signals as spread spectrum modulated signals;
receiving the signals via the at least two antennas;
summing the signals received via the at least two antennas and delaying at least one of the signals received via the at least two antennas so that a path difference between the summed signals is at least one chip of the spread spectrum modulation; and
demodulating the summed signals. - View Dependent Claims (15)
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2. A method of transmitting signals from a satellite having at least two antennas whose radiation patterns overlap, at least in part, and means for sending the signals, the method comprising:
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spread spectrum modulating the signals to be transmitted;
sending the spread spectrum modulated signals to the at least two antennas; and
transmitting the spread spectrum modulated signals via the at least two antennas, the spread spectrum modulated signals transmitted via the at least two antennas being offset by at least one chip of the spread spectrum modulation. - View Dependent Claims (3, 4)
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5. A method of transmitting signals from a satellite having at least two antennas whose radiation patterns overlap, at least in part, and means for sending signals, the method comprising the following steps:
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spread spectrum modulating the signals to be transmitted;
sending the modulated signals to the at least two antennas; and
transmitting the signals via the at least two antennas, the signals transmitted via the at least two antennas being spread spectrum modulated using different sequences.
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6. A satellite comprising:
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at least two antennas whose radiation patterns overlap, at least in part, receiver means for receiving the sum of signals received by the at least two antennas, wherein the receiver means comprise means for demodulating a spread spectrum signal, and the absolute difference between respective transmission times of the signals received by the receiver means via the at least two antennas is greater than one chip of a spread spectrum modulation. - View Dependent Claims (7, 8, 9)
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10. A satellite comprising:
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at least two antennas whose radiation patterns overlap, at least in part, and transmitter means for transmitting signals via the at least two antennas, wherein the transmitting means comprise means for spread spectrum modulating the signals, and an absolute difference between respective transmission times of the signals transmitted by the transmitter means via the at least two antennas is greater than one chip of the spread spectrum modulation. - View Dependent Claims (12, 13, 14, 16)
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11. A satellite comprising:
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at least two antennas whose radiation patterns overlap, at least in part, and transmitter means for sending signals to the various at least two antennas, wherein the transmitter means comprise means for spread spectrum modulating the signals intended for transmission via the at least two antennas using different sequences.
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Specification