System for dual frequency range mobile two-way satellite communications
View Patent ↗A microwave antenna terminal for two-way, in-motion communication systems using geostationary or other orbit satellites, and capable of supporting two-way communication in two different frequency ranges, for example Ku and Ka frequency ranges, is provided.
1. An apparatus, comprising:
a rotating platform comprising a first antenna panel and a second antenna panel, wherein the first antenna panel is configured for transmitting and receiving in a first frequency band, and wherein the second antenna panel is configured for transmitting and receiving in a second frequency band;
a control system comprising one or more sensors and at least one processor;
a tuner configured to receive a signal via at least one of the first antenna panel or the second antenna panel;
a filter coupled to an output of the tuner and configured to provide a filtered signal; and
a converter coupled to an output of the filter and configured to provide samples of the filtered signal to the at least one processor,
wherein the at least one processor is configured to control movement of the rotating platform using information received from the one or more sensors and to use the tuner, the filter, and the converter to detect a first signal.
2. The apparatus of claim 1 , wherein the at least one processor is further configured to:
calculate a Fast Fourier Transform (FFT) using samples of the filtered signal;
calculate a signal power magnitude for each bin of the FFT; and
identify a bin of the FFT that corresponds to a maximum signal power magnitude.
3. The apparatus of claim 1 , wherein the tuner is a zero intermediate-frequency (IF) tuner and the at least one processor is configured to search, in parallel, for a satellite carrier signal in frequency range [−f s /2, f s /2] symmetrically located around zero IF tuner frequency (f t ), wherein f s represents a sampling frequency of the converter.
4. The apparatus of claim 1 , wherein the at least one processor is configured to search for a satellite beacon frequency using one or more azimuth searching cycles, and is further configured to overcome a frequency uncertainty larger than f s /2 in the satellite beacon frequency by shifting the zero IF tuner frequency (f t ) after each azimuth searching cycle.
5. The apparatus of claim 4 , wherein the at least one processor is configured to identify a satellite using a combination of a determined satellite beacon frequency and a satellite heading relative to North.
6. The apparatus of claim 1 , wherein the first frequency band is a Ku frequency band.
7. The apparatus of claim 1 , wherein the second frequency band is a Ka frequency band.
8. The apparatus of claim 1 , wherein at least one of the first antenna panel or the second antenna panel comprise one or more plastic materials and a conductive coating.
9. An apparatus, comprising:
a rotating platform comprising a first antenna panel and a second antenna panel, wherein the first antenna panel is configured for transmitting and receiving in a first frequency band, and wherein the second antenna panel is configured for transmitting and receiving in a second frequency band;
a baseband low-pass filter;
a logarithmic detector; and
a control system comprising one or more sensors and at least one processor, wherein the at least one processor is configured to control movement of the rotating platform using information received from the one or more sensors and to use the baseband low-pass filter and the logarithmic detector to detect a first signal.
10. The apparatus of claim 9 , further comprising a switch configured to allow the baseband low-pass filter to be bypassed, wherein the at least one processor is configured to utilize the switch to bypass the baseband low-pass filter to detect a second signal.
11. The apparatus of claim 9 , wherein the first frequency band is a Ku frequency band.
12. The apparatus of claim 9 , wherein the second frequency band is a Ka frequency band.
13. The apparatus of claim 9 , wherein at least one of the first antenna panel or the second antenna panel comprise one or more plastic materials and a conductive coating.
14. An apparatus, comprising:
a rotating platform comprising a first antenna panel and a second antenna panel, wherein the first antenna panel is configured for transmitting and receiving in a first frequency band, and wherein the second antenna panel is configured for transmitting and receiving in a second frequency band;
a reference system configured to indicate an antenna heading; and
a control system comprising one or more sensors and at least one processor, wherein the at least one processor is configured to:
control movement of the rotating platform using information received from the one or more sensors;
perform at least one azimuth search cycle using a first range of azimuth values for finding a satellite if the reference system is not locked; and
perform at least one azimuth search cycle using a second range of azimuth values for finding the satellite if the reference system is locked,
wherein the second range of azimuth values is a subset of the first range of azimuth values.
15. The apparatus of claim 14 , wherein the at least one processor is configured to identify a satellite using a combination of a determined satellite beacon frequency and a satellite heading relative to North.
16. The apparatus of claim 14 , wherein the at least one processor is configured to:
convert satellite coordinates to earth centered earth fixed (ECEF) coordinates; and
convert ECEF coordinates to coordinates corresponding to the rotating platform and to at least one of the first antenna panel or the second antenna panel.
17. The apparatus of claim 14 , wherein the first frequency band is a Ku frequency band.
18. The apparatus of claim 14 , wherein the second frequency band is a Ka frequency band.
19. The apparatus of claim 14 , wherein at least one of the first antenna panel or the second antenna panel comprise one or more plastic materials and a conductive coating.
20. The apparatus of claim 14 , wherein the at least one processor is configured to use information received from any of an external inertial navigation system (INS) and a global positioning system (GPS) receiver for pointing at least one of the first antenna panel and the second antenna panel towards a satellite.