Retroreflecting transponder
First Claim
1. A method for transmitting signals from transmitters into areas surrounding these transmitters via a satellite, comprising the steps ofproviding a satellite having a retrodirective antenna array comprising an array of receiving antenna elements defining a pattern of positions of the receiving antenna elements, and an array of transmitting antenna elements defining a pattern of positions of the transmitting antenna elements,receiving, by the array of receiving antenna elements of the retrodirective antenna array, a plurality of first signals each having an uplink frequency and being transmitted from individual transmitters,processing the received first signals for obtaining transformed signals by:
- A/D converting the received first signals from analog to digital signals at individual sampling times,performing a Fourier transformation on the digital signals from space domain into space spectral domain for each sampling time,performing a digital frequency conversion from an uplink frequency band to a downlink frequency band,digital phase shifting of the space spectral domain components according to the frequency difference between the uplink and downlink frequency bands by complex multiplication,performing an inverse Fourier transformation to phase-shifted space spectral domain components from the space spectral domain to space domain,center-symmetrical mirroring the pattern of the positions of the receiving antenna elements, andD/A converting the transformed signals, andapplying the transformed signals to the transmitting antenna elements of the retrodirective antenna array in accordance with the center-symmetrical mirrored pattern of the positions of the transmitting antenna elements.
2 Assignments
0 Petitions
Accused Products
Abstract
The Method for transmitting a signal from a transmitter in an area around the transmitter via a satellite comprising the steps of
- transmitting a first signal having a first frequency from the transmitter to a satellite having a retrodirective antenna array comprising receiving antennas and transmitting antennas,
- receiving the signal transmitted from the transmitter by the receiving antennas of the retrodirective antenna array as first signals wherein the first signals received by the receiving antennas have a phase relation among each other defined by the geometric arrangement of the receiving antennas, and
- retrodirectively re-transmitting second signals from the transmitting antennas of the antenna array of the satellite in the direction towards the transmitter in the form of a beam with the transmitter located substantially in the center of the beam wherein the second signal has a second frequency different from the first frequency and wherein the phase relations among the second signal transmitted from the transmitting antennas of the antenna array of the satellite are substantially the same as the phase relations among the first signals received by the receiving antennas of the antenna array of the satellite.
17 Citations
9 Claims
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1. A method for transmitting signals from transmitters into areas surrounding these transmitters via a satellite, comprising the steps of
providing a satellite having a retrodirective antenna array comprising an array of receiving antenna elements defining a pattern of positions of the receiving antenna elements, and an array of transmitting antenna elements defining a pattern of positions of the transmitting antenna elements, receiving, by the array of receiving antenna elements of the retrodirective antenna array, a plurality of first signals each having an uplink frequency and being transmitted from individual transmitters, processing the received first signals for obtaining transformed signals by: -
A/D converting the received first signals from analog to digital signals at individual sampling times, performing a Fourier transformation on the digital signals from space domain into space spectral domain for each sampling time, performing a digital frequency conversion from an uplink frequency band to a downlink frequency band, digital phase shifting of the space spectral domain components according to the frequency difference between the uplink and downlink frequency bands by complex multiplication, performing an inverse Fourier transformation to phase-shifted space spectral domain components from the space spectral domain to space domain, center-symmetrical mirroring the pattern of the positions of the receiving antenna elements, and D/A converting the transformed signals, and applying the transformed signals to the transmitting antenna elements of the retrodirective antenna array in accordance with the center-symmetrical mirrored pattern of the positions of the transmitting antenna elements. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification