System and method for generating high-resolution imagery using electromagnetic signals

• US 10,698,103 B2
• Filed: 06/16/2017
• Issued: 06/30/2020
• Est. Priority Date: 06/16/2017
• Status: Active Grant

• Current Assignee: BAE Systems Information and Electronic Systems Integration Incorporated (BAE Systems Plc)
• Original Assignee: BAE Systems Information and Electronic Systems Integration Incorporated (BAE Systems Plc)
• Inventors: Weichman, Peter B., Ekhaus, Ira
• Primary Examiner(s): Brainard, Timothy A
• Application Number:
  US15/625,468
• Publication Number:
  US 20180364351A1
• Time in Patent Office: 1,110 Days
• CPC Class Codes: G01S 13/90 using synthetic aperture techniques , e.g. synthetic aperture radar [SAR] techniques
• CPC Class Codes: G01S 7/20 Stereoscopic displays; Three-dimensional displays; Pseudo-three-dimensional displays

Abstract

A system and method for generating high-resolution imagery using electromagnetic signals includes a moveable vehicle and a multiple-input multiple-output (MIMO) radar system carried by the vehicle. The MIMO radar system includes an antenna array having a plurality of antenna elements. One or more of the antenna elements transmits electromagnetic signals towards a target area and one or more of the antenna elements receives back-scattered electromagnetic signals reflected from the target area. The system generates high-resolution three-dimensional imagery based on back-scattered electromagnetic signal data with system performance characterized by: (a) down range resolution ΔR; (b) cross-range resolution ΔX; and (c) vertical resolution ΔH. The system exploits effective synthetic apertures to improve cross-range resolution ΔX and vertical resolution ΔH based on, at least in part, the movement of the vehicle along the trajectory and a width and height of the antenna array relative to the target area.

Claims

1. A system for generating high-resolution imagery using electromagnetic signals comprising:

a moveable vehicle;

a multiple-input multiple-output (MIMO) radar system carried by the vehicle, the MIMO radar system comprising a nominally forward-looking one-dimensional antenna array having a plurality of antenna elements configured to be transmitters and receivers;

wherein the vehicle and the nominally forward-looking one-dimensional antenna array move in a nominally forward moving trajectory forming effective synthetic apertures in a nominal first and second direction; and

wherein the plurality of antenna elements transmits electromagnetic signals towards a target area; and

wherein the plurality of antenna elements receives back-scattered electromagnetic signals reflected from the target area; and

at least one non-transitory computer readable storage medium having instructions encoded thereon that, when executed by one or more processors, result in the following operations for generating high-resolution three-dimensional imagery based on back-scattered electromagnetic signal data with system performance characterized by;

(a) down range resolution Δ

R;

(b) cross-range resolution Δ

X; and

(c) vertical resolution Δ

H;

the operations configured to exploit the effective synthetic apertures in the nominal first and second direction to improve cross-range resolution Δ

X and vertical resolution Δ

H based on, at least in part, the movement of the vehicle along the nominally forward moving trajectory and a width and height of the nominally forward-looking one-dimensional antenna array relative to the target area.

2. The system of claim 1, wherein the nominally forward-looking one-dimensional antenna array is a nominally forward-looking one-dimensional sparse antenna array.

3. The system of claim 2, wherein the antenna elements of the nominally forward-looking one-dimensional sparse antenna array are steerable.

4. The system of claim 2, the antenna elements of the nominally forward-looking one-dimensional sparse antenna array are fixed.

5. The system of claim 1, wherein the antenna elements are irregularly spaced.

6. The system of claim 1, wherein the nominally forward-looking one-dimensional antenna array is a nominally forward-looking one-dimensional dense antenna array.

7. The system of claim 1, wherein each of the antenna elements is configured to transmit sequentially while the plurality of antenna elements receive the back-scattered electromagnetic signals.

8. The system of claim 1, wherein the plurality of antenna elements are configured to transmit simultaneously with orthogonal coded waveforms and the plurality of antenna elements receive the back-scattered electromagnetic signals.

9. The system of claim 1, wherein the nominally forward moving trajectory that develops the effective synthetic apertures in the nominal first and second direction comprises perturbations from a nominal linear glide slope;

and wherein the perturbations are measured by an inertial measurement unit.

10. The system of claim 1, wherein the plurality of antenna elements are configured as pairs of transmitter antenna elements and pairs of receiver antenna elements.

11. The system of claim 1, wherein the plurality of antenna elements are configured as multiple transmitters and multiple receivers.

12. A system for generating high-resolution imagery using electromagnetic signals comprising:

a moveable vehicle;

a multiple-input multiple-output (MIMO) radar system carried by the vehicle, the MIMO radar system comprising a nominally forward-looking one-dimensional antenna array having a plurality of antenna elements configured to be transmitters and receivers;

wherein the vehicle and the nominally forward-looking one-dimensional antenna array move in a nominally forward moving trajectory forming an effective synthetic aperture in a nominal first direction; and

wherein the plurality of the antenna elements transmits electromagnetic signals towards a target area; and

wherein the plurality of the antenna elements receives back-scattered electromagnetic signals reflected from the target area; and

at least one non-transitory computer readable storage medium having instructions encoded thereon that, when executed by one or more processors, result in the following operations for generating high-resolution three-dimensional imagery based on back-scattered electromagnetic signal data, the operations configured to exploit the effective synthetic aperture in the nominal first direction to improve the vertical resolution Δ

H based on, at least in part, the movement of the vehicle in the nominally forward moving trajectory and a height of the nominally forward-looking one-dimensional antenna array relative to the target area.

13. A method for generating high-resolution imagery using electromagnetic signals comprising:

mounting a multiple-input multiple-output (MIMO) radar system including a nominally forward-looking one-dimensional antenna array having a plurality of antenna elements on a vehicle;

moving the vehicle in a forward trajectory;

forming effective synthetic apertures in a nominal first and second direction;

transmitting electromagnetic signals using the plurality of the antenna elements towards a target area;

illuminating the target area;

receiving back-scattered electromagnetic signals reflected from the target area at the plurality of the antenna elements;

processing the received back-scattered electromagnetic signals;

generating a three-dimensional image with system performance characterized by;

(a) down range resolution Δ

R;

(b) cross-range resolution Δ

X; and

(c) vertical resolution Δ

H; and

displaying the three-dimensional image.

14. The method of claim 13, wherein the nominally forward-looking one-dimensional antenna array is a nominally forward-looking one-dimensional sparse antenna array.

15. The method of claim 14, wherein the antenna elements of the nominally forward-looking one-dimensional sparse antenna array are steerable.

16. The method of claim 14, the antenna elements of the nominally forward-looking one-dimensional sparse antenna array are fixed.

17. The method of claim 13, wherein the antenna elements are irregularly spaced.

18. The method of claim 13, wherein the nominally forward-looking one-dimensional antenna array is a nominally forward-looking one-dimensional dense antenna array.

19. The method of claim 13, wherein the nominally forward-looking one-dimensional antenna array of the MIMO radar system forms a combination of radar transmissions and receptions and collects associated data which includes a combination of real aperture data and synthetic aperture data.

20. The method of claim 19, further comprising:

utilizing three-dimensional back-projection image formation instructions to process the combination of real aperture data and the synthetic aperture data; and

generating a raw three-dimensional scene map.

21. The method of claim 20, further comprising:

utilizing rendering display instructions to display the processed combination of real aperture data and synthetic aperture data as real-time pilotage quality imagery.

22. The method of claim 13, wherein each of the antenna elements is configured to transmit sequentially while the plurality of antenna elements receive the back-scattered electromagnetic signals.

23. The method of claim 13, wherein the plurality of antenna elements are configured to transmit simultaneously with orthogonal coded waveforms and the plurality of antenna elements receive the back-scattered electromagnetic signals.