SIGNAL PROCESSING DEVICE

• US 20170269193A1
• Filed: 08/20/2014
• Published: 09/21/2017
• Est. Priority Date: 08/20/2014
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: YAMAOKA, Tomoya
• Granted Patent: US 10,754,006 B2
• Time in Patent Office: Days
• CPC Class Codes: G01S 13/53 performing filtering on a single spectral line and associated with one or more range gates with a phase detector or a frequency mixer to extract the Doppler information, e.g. pulse Doppler radar G01S13/5244 takes precedence
• CPC Class Codes: G01S 13/9029 specially adapted for moving target detection within a single SAR image or within multiple SAR images taken at the same time
• CPC Class Codes: G01S 7/292 Extracting wanted echo-signals

Abstract

Disclosed is a signal processing device including a rearrangement unit 3 for rearranging the spectrum of a signal component outputted from a signal restoring unit 1 in such a way that a stationary target component and an aliasing component associated with a moving target, the stationary target component and the aliasing component being included in the signal component, and a moving target component included in the signal component are separate on a frequency domain, and a formation unit 4 for suppressing the stationary target component and the aliasing component associated with the moving target, the stationary target component and the aliasing component being included in the signal component whose spectrum is rearranged by the rearrangement unit 3, thereby extracting the moving target component included in the signal component after the spectrum rearrangement, in which a moving target image reconstructing unit 5 reconstructs an image of the moving target from the moving target component extracted by the formation unit 4.

Claims

1. A signal processing device comprising:

a signal combining means for, when a plurality of reception antennas, the reception antennas being disposed along an orbital direction of a platform in which a radar device is mounted, receive signals which are included in signals repeatedly transmitted from a transmitting antenna and which are reflected by a stationary target or a moving target, combining the received signals of said plurality of reception antennas in such a way that aliasing noise components associated with said stationary target and included in the received signals of said plurality of reception antennas are canceled out, and outputting a composite signal;

a moving target component extracting means for suppressing a stationary target component and an aliasing noise component associated with said moving target, the stationary target component and the aliasing noise component being included in the composite signal outputted from said signal combining means, and extracting a moving target component included in said composite signal; and

an image reconstructing means for reconstructing an image of said moving target from the moving target component extracted by said moving target component extracting means.

2. The signal processing device according to claim 1, wherein said signal combining means converts the received signals of said plurality of reception antennas into signals in a frequency domain, combines said plurality of signals in the frequency domain in such a way that aliasing noise components associated with said stationary target and included in said plurality of signals in the frequency domain are canceled out, and outputs the composite signal.

3. The signal processing device according to claim 2, wherein said signal combining means cyclically shifts said plurality of signals in the frequency domain by one-half of a pulse repetition frequency of the signals transmitted from said transmitting antenna, combines said plurality of signals in the frequency domain after the cyclic shift in such a way that the aliasing noise components associated with said stationary target and included in said plurality of signals in the frequency domain after the cyclic shift are canceled out, and outputs the composite signal.

4. The signal processing device according to claim 1, wherein said signal combining means arranges the received signals of said plurality of reception antennas alternately on a time domain, and, thereafter, combines the received signals of said plurality of reception antennas and outputs the composite signal.

5. The signal processing device according to claim 2, wherein said moving target component extracting means comprises:

a rearrangement unit for rearranging a spectrum of said composite signal in such a way that the stationary target component and the aliasing noise component associated with said moving target, the stationary target component and the aliasing noise component being included in the composite signal outputted from said signal combining means, and the moving target component included in said composite signal are separate on the frequency domain; and

a formation unit for suppressing the stationary target component and the aliasing noise component associated with said moving target, the stationary target component and the aliasing noise component being included in the composite signal whose spectrum is rearranged by said rearrangement unit, and extracting the moving target component included in said composite signal.

6. The signal processing device according to claim 5, wherein when rearranging the spectrum of said composite signal, said rearrangement unit makes a copy of a signal which is a part included in said composite signal and performs replacement.

7. The signal processing device according to claim 2, wherein said moving target component extracting means performs a range cell migration process and a matched filter process for azimuth compression on said composite signal in such a way that the stationary target component and the aliasing noise component associated with said moving target are suppressed, the stationary target component and the aliasing noise component being included in the composite signal outputted from said signal combining means, thereby extracting the moving target component included in said composite signal.

8. The signal processing device according to claim 1, wherein said image reconstructing means detects pixels having a larger amplitude value than a preset threshold from among pixels which construct the image of said moving target, thereby detecting said moving target.

9. The signal processing device according to claim 1, wherein said image reconstructing means performs a filtering process of detecting an edge on pixels which construct the image of said moving target.

10. The signal processing device according to claim 1, wherein said image reconstructing means reconstructs an image of said stationary target from the stationary target component included in the composite signal outputted from said signal combining means.

11. The signal processing device according to claim 10, wherein said image reconstructing means applies different colors to the image of said moving target and the image of said stationary target, and, thereafter, superimposes the image of said moving target and the image of said stationary target on each other.