Concurrent airborne communication methods and systems

• US 8,767,615 B2
• Filed: 09/21/2012
• Issued: 07/01/2014
• Est. Priority Date: 09/21/2011
• Status: Active Grant

• Current Assignee: Spatial Digital Systems Inc
• Original Assignee: Spatial Digital Systems Inc
• Inventors: Chang, Donald C. D.
• Primary Examiner(s): Duong, Frank
• Application Number:
  US13/623,882
• Publication Number:
  US 20130070677A1
• Time in Patent Office: 648 Days
• Field of Search: 370315-325, 370328-339, 370535-542, 342/154, 342/354, 455/3.02, 455/427, 455/431, 455/11.1, 455/12.1
• US Class Current: 370/316
• CPC Class Codes: B64U 2101/20 for use as communications relays, e.g. high-altitude platforms
• CPC Class Codes: G01S 13/933 of aircraft or spacecraft
• CPC Class Codes: G01S 7/006 using shared front-end circuitry, e.g. antennas G01S13/765, G01S13/825 take precedence
• CPC Class Codes: H04B 10/2581 Multimode transmission
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04B 7/18502 Airborne stations
• CPC Class Codes: H04B 7/18504 Aircraft used as relay or high altitude atmospheric platform
• CPC Class Codes: H04B 7/18515 Transmission equipment in satellites or space-based relays
• CPC Class Codes: H04B 7/18517 Transmission equipment in earth stations
• CPC Class Codes: H04B 7/18523 Satellite systems for providing broadcast service to terrestrial stations, i.e. broadcast satellite service arrangements specially adapted for satellite broadcast receiving H04H40/90; picture transmission via satellite H04N1/00103; television transmission via satellite H04N7/20
• CPC Class Codes: H04B 7/2041 Spot beam multiple access
• CPC Class Codes: H04J 14/00 Optical multiplex systems
• CPC Class Codes: H04J 14/005 Optical Code Multiplex
• CPC Class Codes: H04J 14/02 Wavelength-division multiplex systems
• CPC Class Codes: H04J 14/0307 Multiplexers; Demultiplexers
• CPC Class Codes: H04J 14/08 Time-division multiplex systems
• CPC Class Codes: H04L 25/03006 Arrangements for removing intersymbol interference
• CPC Class Codes: H04L 25/03891 Spatial equalizers MIMO diversity systems H04B7/0413

Abstract

Aircrafts or unmanned air vehicles flying near Earth are used as airborne communications towers or relays. Using techniques of ground based beam forming and wavefront multiplexing enhance the ability to coherently combine the power of the communication signals, and improve the signal-to-noise ratio.

Claims

1. A communication system comprising:

a set of communication equipment divided among airborne vehicles;

wherein a first subset of the set of communication equipment, mounted on a first airborne vehicle, defines a roving communication tower in a foreground region;

wherein the set of communication equipment, mounted among each of the airborne vehicles, has data receivers to communicate with on-ground devices or with a hub or with a ground based beam forming (GBBF) facility; and

wherein the data receivers connect to receive wavefront multiplexed (WF MUX) signal components wherein one of the WF MUX signal components is a multiplexed diagnostic code.

2. The communication system of claim 1, wherein the airborne vehicles are un-manned.

3. The communication system of claim 1, wherein the set of communication equipment includes retro-directive arrays to communicate with the hub or the GBBF facility at a first frequency band different from a second frequency band used by onboard airborne arrays to communicate with devices located in the foreground region.

4. The communication system of claim 1, wherein the set of communication equipment is configured to send communications at a first frequency to tracking antennas at the hub or at the GBBF facility in the background region, wherein the communications include position information of each of the airborne vehicles.

5. The communication system of claim 1 further comprising an array antenna on one of the air vehicles that is arranged to transmit multiple beams at a second frequency band to devices in the foreground region, wherein beam formation data is provided by the hub or the GBBF facility.

6. The communication system of claim 1 further comprises antennas to receive beam formations from a digital beam forming (DBF) processor circuit on the GBBF facility.

7. The communication system of claim 1, wherein the set of communication equipment includes data transmitters operating at a second frequency band to communicate with devices having omni-directional or directional antennas located in the foreground region.

8. The communication system of claim 1, wherein the WF MUX signal components are generated by a multiplexer set up to perform Butler or Hadamard or Fourier transformations on an original diagnostic code and on data.

9. The communication system of claim 1, wherein the set of communication equipment comprises dynamic signal equalization to maintain coherency among the WF MUX signal components relayed by each of the airborne vehicles.

10. A roving communication structure comprising:

a set of communication equipment for mounting among airborne vehicles;

a first subset of the set of communication equipment to define a roving communication tower in a foreground region;

the set of communication equipment includes data receivers to communicate with an on-ground wavefront multiplexer;

the set of communication equipment includes data transmitters to communicate with a corresponding on-ground wavefront demultiplexer; and

wherein the data receivers process wavefront multiplexed (WF MUX) signal components.

11. The roving communication structure of claim 10, wherein the WF MUX signal components are generated by the on-ground wavefront multiplexer programmed to perform transformations of orthogonal elements.

12. The roving communication structure of claim 10, wherein the WF MUX signal components come from the on-ground wavefront multiplexer that connects to receive signals and a diagnostic code.

13. The roving communication structure of claim 12, wherein the WF MUX signal components derive from transformations of input signals and a diagnostic code, wherein the transformations comprise Butler matrix devices or Hadamard circuits.

14. An airborne communication method comprising:

operating a set of communication equipment divided among airborne vehicles;

using a first subset of the set of communication equipment on a first airborne vehicle to create a roving communication tower that communicates with devices in a foreground region;

using retro-directive arrays onboard the airborne vehicles to transmit and receive data between the set of communication equipment and a hub or a GBBF facility located in a background region;

receiving a wavefront multiplexed (WF MUX) diagnostic code from outputs of a wavefront multiplexer;

receiving WF MUX signal components from the same outputs of the wavefront multiplexer; and

wherein the WF MUX diagnostic code is associated with a transformation of an original diagnostic code and communication signals.

15. The airborne communication method of claim 14, wherein the transformation comprises forming communication beams using Butler matrices or Hadamard transforms.

16. The airborne communication method of claim 14, wherein the retro-directive arrays processes the received data by analog beam forming devices and by switches.

17. The airborne communication method of claim 14 further comprising transmitting a first data to and receiving a second data from the foreground region using an on-board array antenna with multiple array elements operating in a second frequency band.

18. The airborne communication method of claim 14 further comprising transmitting signals from an onboard beam forming network associated with a first antenna array antenna that communicates with devices in the foreground region.

19. The airborne communication method of claim 14 further comprising receiving beam formed data from the GBBF facility;

and relaying the beam formed data to a foreground region using a first antenna array that communicates with devices in the foreground region.

20. The airborne communication method of claim 14 further comprising receiving calibration signals from the GBBF facility, wherein the calibration signals compensate for distance variations among the airborne vehicles.