Controlling data collection to support SAR image rotation
View Patent ↗A desired rotation of a synthetic aperture radar (SAR) image can be facilitated by adjusting a SAR data collection operation based on the desired rotation. The SAR data collected by the adjusted SAR data collection operation can be efficiently exploited to form therefrom a SAR image having the desired rotational orientation.
1. A synthetic aperture radar (SAR) method, comprising:
providing a SAR data collection operation that normally collects first SAR data from which can be formed a first SAR image that corresponds to a target and is oriented in a predetermined reference orientation;
adjusting the SAR data collection operation based on a predetermined amount of rotation by which a second SAR image corresponding to the target is to be rotated relative to said predetermined reference orientation; and
collecting second SAR data according to the adjusted SAR data collection operation.
2. The method of claim 1 , including forming the second SAR image based on the second SAR data, the second SAR image rotated by said predetermined amount relative to said predetermined reference orientation.
3. The method of claim 2 , including reducing distortion in the second SAR data based on said predetermined amount of rotation.
4. The method of claim 1 , wherein said adjusting includes adjusting one of a waveform parameter, a timing parameter, and an angular position parameter associated with a radar pulse.
5. The method of claim 4 , wherein said waveform parameter includes one of center frequency and chirp rate.
6. The method of claim 5 , wherein said timing parameter includes one of digital sampling delay and digital sample spacing.
7. The method of claim 6 , wherein said angular position parameter includes aspect angle.
8. The method of claim 4 , wherein said timing parameter includes one of digital sampling delay and digital sample spacing.
9. The method of claim 8 , wherein said angular position parameter includes aspect angle.
10. The method of claim 4 , wherein said angular position parameter includes aspect angle.
11. The method of claim 10 , wherein said waveform parameter includes one of center frequency and chirp rate.
12. The method of claim 4 , including adjusting said angular position parameter, and adjusting said waveform parameter based on the adjusted angular position parameter.
13. The method of claim 12 , including adjusting said angular position parameter, and adjusting said timing parameter based on the adjusted angular position parameter.
14. A SAR method, comprising:
receiving first SAR data that has been collected using a SAR data collection operation that has been adjusted to collect the first SAR data based on a predetermined amount of rotation by which a first SAR image corresponding to a target is to be rotated relative to a predetermined reference orientation, the SAR data collection operation normally collecting second SAR data from which can be formed a second SAR image that corresponds to the target and is oriented in said predetermined reference orientation; and
forming the first SAR image based on the first SAR data, wherein the first SAR image is rotated by said predetermined amount relative to said predetermined reference orientation.
15. A SAR apparatus, comprising:
a SAR data collector for performing a SAR data collection operation that normally collects first SAR data from which can be formed a first SAR image that corresponds to a target and is oriented in a predetermined reference orientation;
an adjuster coupled to said SAR data collector for adjusting the SAR data collection operation based on a predetermined amount of rotation by which a second SAR image corresponding to the target is to be rotated relative to said predetermined reference orientation; and
said SAR data collector responsive to said adjuster for collecting second SAR data according to the adjusted SAR data collection operation.
16. The apparatus of claim 15 , including an image former coupled to said SAR data collector for forming the second SAR image based on the second SAR data, the second SAR image rotated by said predetermined amount relative to said predetermined reference orientation.
17. The apparatus of claim 16 , wherein said image former includes a distortion mitigator coupled to said SAR data collector for reducing distortion in the second SAR data based on said predetermined amount of rotation.
18. The apparatus of claim 17 , wherein said image former includes a Chirped Z-Transform (CZT) processing unit coupled to said SAR data collector and said distortion mitigator, and a Discrete Fourier Transform (DFT) processing unit coupled to said distortion mitigator.
19. A SAR apparatus, comprising:
an input for receiving first SAR data that has been collected using a SAR data collection operation that has been adjusted to collect the first SAR data based on a predetermined amount of rotation by which a first SAR image corresponding to a target is to be rotated relative to a predetermined reference orientation, the SAR data collection operation normally collecting second SAR data from which can be formed a second SAR image of the target that is oriented in said predetermined reference orientation; and
an image former coupled to said input for forming the first SAR image based on the first SAR data, wherein the first SAR image is rotated by said predetermined amount relative to said predetermined reference orientation.