IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0309307
(2006-07-25)
|
등록번호 |
US-8200150
(2012-06-12)
|
발명자
/ 주소 |
- Lopez, Jason
- Dwornik, Glen
- Bezuidenhout, Petrus
- Schefter, Michael
- Kouzmine, Stanislav
- Trajkovic, Sasa
|
출원인 / 주소 |
- Norsat International Inc.
|
인용정보 |
피인용 횟수 :
5 인용 특허 :
1 |
초록
▼
A system for accurate automatic satellite acquisition by a portable satellite terminal. The system includes a software program that coordinates inputs from several measurement aids to control antenna position. These aids include a GPS receiver, antenna azimuth, elevation and polarization angle senso
A system for accurate automatic satellite acquisition by a portable satellite terminal. The system includes a software program that coordinates inputs from several measurement aids to control antenna position. These aids include a GPS receiver, antenna azimuth, elevation and polarization angle sensors, and the terminal's modem, DVB receiver and spectrum analyzer, which contains a beacon detector also serving as Receive Signal Strength Indicator (RSSI). For satellite recognition, the spectral analysis and RSSI function are complemented by the lock/unlock indications provided by the modem and the DVB receiver. Under the control of the software program, the modem, DVB receiver and spectrum analyzer, in conjunction with an extensive database of satellites and their signal characteristics, provide the means for reliable validation of final alignment.
대표청구항
▼
1. A method of determining a peak polarization of a communication signal comprising: a) making a first group of signal strength measurements, wherein said first group of signal strength measurements includes a pair of measurements at each frequency in a first group of frequencies in a receive band o
1. A method of determining a peak polarization of a communication signal comprising: a) making a first group of signal strength measurements, wherein said first group of signal strength measurements includes a pair of measurements at each frequency in a first group of frequencies in a receive band of said signal, wherein each said pair of measurements includes a first signal strength measurement at a polarization angle corresponding to a home polarization and a second signal strength measurement at a polarization opposite to said home polarization;b) selecting at least one frequency from said first group of frequencies for which a corresponding one of said pairs of signal strength measurements has a greater difference between said first signal strength measurement and said second signal strength measurement than the non-selected frequencies from said first group of frequencies;c) making a second group of signal strength measurements, wherein said second group of signal strength measurements includes a plurality of pairs of measurements at each one of said selected frequencies, wherein each said pair of measurements in said second group includes a first signal strength measurement at said home polarization and a second signal strength measurement at said polarization opposite to said home polarization;d) identifying a frequency for which said differences in said pairs of measurements in said second group of signal strength measurements display the lowest variability;e) making a third group of signal strength measurements at said identified frequency, wherein said third group of signal strength measurements includes a plurality of signal strength measurements at each one of a plurality of signal polarization angles, and wherein said plurality of signal polarization angles represents a range of polarization angles about said home polarization;f) for each one of said plurality of signal polarization angles determining an average signal strength measurement;g) approximating said average signal strength measurements for each of said plurality of signal polarization angles with a mathematical function adjusting parameters of said mathematical function to yield a lowest sum-of-squares difference between said mathematical function and said average signal strength measurements;h) determining a peak of said mathematical function for determining a peak polarization angle of the communication signal. 2. The method of claim 1, wherein said signal strength measurements are made at predetermined frequency intervals. 3. The method of claim 2, wherein said signal strength measurements are made at frequency intervals of 10 MHz. 4. The method of claim 1, wherein in said second group of signal strength measurements 10 pairs of measurements are taken at each one of said selected frequencies. 5. The method of claim 1, wherein said polarization angles are separated by intervals of 1 degree and wherein said range of polarization angles about said home polarization extends from 40 degrees to one side of said home polarization to 40 degrees to the other side of said home polarization. 6. The method of claim 1, wherein said third group of signal strength measurements includes 20 measurements at each one of said plurality of signal polarization angles. 7. The method of claim 1, wherein said third group of signal strength measurements are processed to yield an average signal strength value at each one of said plurality of signal polarization angles. 8. The method of claim 7, wherein said average signal strength values and corresponding step-motor step positions are stored in an array. 9. The method of claim 1, wherein after said peak of said function has been determined, a feed of a satellite terminal is aligned with a polarization angle corresponding to said peak of said function. 10. The method of claim 1, wherein said mathematical function is: y=Y Offset+sqrt[sin(x*X Scale+X Offset)]*Y Scalewhere y is signal strength, x is polarization angle, Y Offset is a shift in signal strength, X Offset is a shift in polarization angle, Yscale is a coefficient that modifies signal strength magnitude, and Xscale is a coefficient that adjusts polarization angle magnitude. 11. The method of claim 1, wherein said mathematical function is: y=Y Offset+log[sin(x*X Scale+X Offset)]*Y Scalewhere y is signal strength, x is polarization angle, Y Offset is a shift in signal strength, X Offset is a shift in polarization angle, Yscale is a coefficient that modifies signal strength magnitude, and Xscale is a coefficient that adjusts polarization angle magnitude. 12. A computer program product for determining a peak polarization of a communication signal received by a portable satellite terminal, the program product comprising computer readable program code means for: a) making a first group of signal strength measurements, wherein said first group of signal strength measurements includes a pair of measurements at each frequency in a first group of frequencies in a receive band of said signal, wherein each said pair of measurements includes a first signal strength measurement at a polarization angle corresponding to a home polarization and a second signal strength measurement at a polarization opposite to said home polarization;b) selecting at least one frequency from said first group of frequencies for which a corresponding one of said pairs of signal strength measurements has a greater difference between said first signal strength measurement and said second signal strength measurement than the non-selected frequencies from said first group of frequencies;c) making a second group of signal strength measurements, wherein said second group of signal strength measurements includes a plurality of pairs of measurements at each one of said selected frequencies, wherein each said pair of measurements in said second group includes a first signal strength measurement at said home polarization and a second signal strength measurement at said polarization opposite to said home polarization;d) identifying a frequency for which said differences in said pairs of measurements in said second group of signal strength measurements display the lowest variability;e) making a third group of signal strength measurements at said identified frequency, wherein said third group of signal strength measurements includes a plurality of signal strength measurements at each one of a plurality of signal polarization angles, and wherein said plurality of signal polarization angles represents a range of polarization angles about said home polarization;f) for each one of said plurality of signal polarization angles determining an average signal strength measurement;g) approximating said average signal strength measurements for each of said plurality of signal polarization angles with a mathematical function adjusting parameters of said mathematical function to yield a lowest sum-of-squares difference between said mathematical function and said average signal strength measurements;h) determining a peak of said mathematical function for determining a peak polarization angle of the communication signal. 13. The computer program product of claim 12, wherein said signal strength measurements are made at predetermined frequency intervals. 14. The computer program product of claim 13, wherein said signal strength measurements are made at frequency intervals of 10 MHz. 15. The computer program product of claim 12, wherein in said second group of signal strength measurements 10 pairs of measurements are taken at each one of said selected frequencies. 16. The computer program product of claim 12, wherein said polarization angles are separated by intervals of 1 degree and wherein said range of polarization angles about said home polarization extends from 40 degrees to one side of said home polarization to 40 degrees to the other side of said home polarization. 17. The computer program product of claim 12, wherein said third group of signal strength measurements includes 20 measurements at each one of said plurality of signal polarization angles. 18. The computer program product of claim 12, wherein said third group of signal strength measurements are processed to yield an average signal strength value at each one of said plurality of signal polarization angles. 19. The computer program product of claim 18, wherein said average signal strength values and corresponding step-motor step positions are stored in an array. 20. The computer program product of claim 12, wherein after said peak of said function has been determined, a feed of a satellite terminal is aligned with a polarization angle corresponding to said peak of said function. 21. The computer program product of claim 12, wherein said mathematical function is: y=Y Offset+sqrt[sin(x*X Scale+X Offset)]*Y Scalewhere y is signal strength, x is polarization angle, Y Offset is a shift in signal strength, X Offset is a shift in polarization angle, Yscale is a coefficient that modifies signal strength magnitude, and Xscale is a coefficient that adjusts polarization angle magnitude. 22. The computer program product of claim 12, wherein said mathematical function is: y=Y Offset+log[sin(x*XScale+X Offset)]*Y Scalewhere y is signal strength, x is polarization angle, Y Offset is a shift in signal strength, X Offset is a shift in polarization angle, Yscale is a coefficient that modifies signal strength magnitude, and Xscale is a coefficient that adjusts polarization angle magnitude.
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