Vehicle mounted satellite antenna embedded within moonroof or sunroof

• US 20050146478A1
• Filed: 01/07/2004
• Published: 07/07/2005
• Est. Priority Date: 01/07/2004
• Status: Active Grant

• Current Assignee: The Renda Trust
• Original Assignee: Motia, Inc.
• Inventors: Winters, Jack, Warner, Robert A., Wang, James June-Ming, Yang, Ming-Yaug
• Granted Patent: US 7,227,508 B2
• Time in Patent Office: Days
• US Class Current: 343/771
• CPC Class Codes: H01Q 1/288 Satellite antennas
• CPC Class Codes: H01Q 1/3275 mounted on a horizontal surface of the vehicle, e.g. on roof, hood, trunk
• CPC Class Codes: H01Q 21/005 Slotted waveguides arrays
• CPC Class Codes: H01Q 21/24 Combinations of antenna units polarised in different directions for transmitting or receiving circularly and elliptically polarised waves or waves linearly polarised in any direction circularly polarised patch antennas H01Q9/0428; circularly polarised horns H01Q13/0241; cross-polarised horns H01Q13/0258; polarisation converters H01Q15/242; cross-polarised rear feeds H01Q19/136; crossed polarisation dual antenna H01Q25/001

Abstract

The present invention relates to a vehicle mountable satellite antenna as defined in the claims which is operable while the vehicle is in motion. The satellite antenna of the present invention can be installed on top of (or embedded into) the roof of a vehicle. The antenna is capable of providing high gain and a narrow antenna beam for aiming at a satellite direction and enabling broadband communication to vehicle. The present invention provides a vehicle mounted satellite antenna which has low axial ratio, high efficiency and has low grating lobes gain. The vehicle mounted satellite antenna of the present invention provides two simultaneous polarization states.

Claims

1. A vehicle mounted antenna system comprising:

a satellite antenna; and

mounting means for movably mounting said satellite antenna adjacent to a moonroof and/or sunroof system,

wherein said satellite antenna is adapted to be moveable into an open position beneath a plate of said moonroof and/or sunroof system and into a closed position beneath a roof of said vehicle.

2. The system of claim 1 wherein said plate is transparent.

3. The system of claim 1 wherein said mounting means comprises drive means for automatically moving said satellite antenna between said open position and said closed position.

4. The system of claim 1 further comprising:

tracking means coupled to said satellite antenna for aiming said satellite antenna on a selected satellite while the vehicle is in motion.

5. The system of claim 1 wherein said tracking means comprises:

automatic in-motion beam forming tracking means for positioning said antenna array on a selected satellite while the vehicle is in motion.

6. The system of claim 5 wherein said automatic in-motion tracking means comprises means for detecting a left beam and a right beam to obtain information about antenna pointing error in an azimuth direction and an up beam and a down beam to obtain information about antenna pointing error in an elevation direction.

7. The system of claim 6 wherein a sum beam is formed as a combination of said left beam, said right beam, said up beam and said down beam, signal powers of said left beam and said right beam are compared against each other and said sum beam to obtain said information of antenna pointing error in an azimuth direction and signal powers of said up beam and said down beam are compared against one another and said sum beam to obtain said information of antenna pointing error in an elevation direction.

8. The system of claim 7 wherein said antenna array is coupled to a platform and further comprising moving means for moving said platform said moving means using said pointing error in an azimuth direction for moving said platform in an azimuth direction and said pointing error in an elevation error for moving said platform in an elevation direction.

9. The system of claim 1 wherein said satellite antenna comprises:

an antenna array to receive a satellite signal, said antenna array comprising a plurality of waveguides positioned parallel to one another for guiding received electromagnetic waves of said satellite signal;

a radiating surface disposed adjacent to said waveguides; and

at least one radiating element emitting said electromagnetic waves, said at least one radiating elements being distributed along said radiating surface.

10. The system of claim 9 wherein said waveguides include a ridged portion extending from a bottom surface, said ridge portion positioned longitudinally between a pair of walls coupled to said bottom surface.

11. The system of claim 9 wherein each of said radiating elements is an X-shaped cross slot.

12. The system of claim 11 wherein a crossing angle of said X-shaped cross slot is other than about 90 degrees.

13. The system of claim 12 wherein said radiating elements are positioned about half a waveguide wavelength apart from one another.

14. The system of claim 12 wherein said radiating elements are positioned at an offset from a center of a waveguide axis of said waveguide toward one of said walls.

15. The system of claim 12 wherein said radiating elements are equally spaced apart.

16. The system of claim 9 wherein said waveguides have a substantially inverted L-shape including a wall extending vertically downward from said radiating surface.

17. The system of claim 16 further comprising:

a ridged portion extending from said radiating surface at an opposite end from said wall.

18. The system of claim 17 wherein said ridge portion has a predetermined height and a predetermined width for determining depth of a groove between said ridge portion and said wall.

19. The system of claim 16 wherein each of said radiating elements is an X-shaped cross slot.

20. The system of claim 16 wherein a crossing angle of said X-shaped cross slot is other than about 90 degrees.

21. The system of claim 16 wherein said radiating elements are positioned about half a waveguide wavelength apart from one another.

22. The system of claim 16 wherein said radiating elements are positioned at an offset from a center of said radiating surface of said waveguide toward one of said walls.

23. The system of claim 16 wherein said radiating elements are equally spaced apart.

24. The system of claim 9 further comprising:

adaptive beam forming means for determining from said satellite signal automatic in-motion positioning of said one or more satellite antennas while the vehicle is in motion;

wherein said adaptive beam forming means determines a set of antenna weights to optimize an output signal-to-noise ratio of an output signal from each of said waveguides.

25. The system of claim 24 wherein said weights are determined by maximal ratio combining (MRC) to align phases of said output signal from each of said waveguides to the same phase and to scale said output signal from each of said waveguides in proportion to a square root of a received signal-to-noise ratio.

26. The system of claim 24 wherein said weights are determined by:

means for determining a complex error signal by a complex conjugate multiplication of each of said input signals and a reference complex signal.

27. The system of claim 1 wherein the satellite signal comprises a direct broadcast satellite signal.