Spectrometric synthetic aperture radar
View Patent ↗This invention relates to improved ultra-wideband synthetic aperture radar and inverse synthetic aperture radar, capable of simultaneously and independently imaging a plurality of spectral and polarimetric channels covering multiple radio frequency octaves. Advances in technologies relating to signal processing, graphical user interfaces, color representations of multi-spectral radar images, low aerodynamic drag polarimetric SAR antenna systems, and synthetic aperture radar aircraft platforms are some of the advancements disclosed herein.
1. A log periodic tripole antenna comprising:
three log periodic monopole arrays positioned with the feeds parallel,
wherein said arrays comprise rows of antenna elements,
and wherein said rows are spaced 120 degrees apart; and
an airfoil at least partially enclosing one of said rows on antenna elements.
2. The log periodic tripole antenna array of claim 1 wherein said airfoil comprises a lifting, stabilizing, or control surface.
3. The log periodic tripole antenna array of claim 2 wherein said airfoil is a wing.
4. The log periodic tripole antenna array of claim 3 wherein said airfoil is an anhedral wing.
5. The log periodic tripole antenna array of claim 4 further comprising an airfoil enclosure enclosing one of said arrays.
6. The log periodic tripole antenna array of claim 5 wherein said airfoil enclosure comprises an aircraft lifting or control surface.
7. The log periodic tripole antenna array of claim 6 wherein said airfoil enclosure is a wing.
8. The log periodic tripole array in accordance with claim 7 wherein said airfoil enclosure comprises an anhedral wing.
9. The log periodic tripole array of claim 8 wherein the said antenna elements have a vertical surface area in excess of that needed for structural stability.
10. The log periodic tripole array of claim 9 wherein said airfoil enclosure is a wing that include horizontal surface in excess of that needed to surround the antenna elements of said array which is enclosed by said airfoil enclosure.
11. The log periodic tripole array of claim 8 further comprising an additional antenna element and wherein said additional antenna element comprises an aircraft fuselage.
12. The log periodic tripole array of claim 8 further comprising stiffening elements, wherein said stiffening elements strengthen said log periodic tripole array to facilitate its use on an aircraft with a radome.
13. The log periodic tripole array of claim 9 wherein said anhedral wing has been aerodynamically shaped to facilitate its use on an aircraft without a radome.
14. The log periodic tripole array of claim 10 further comprising an internal stiffener and fairing to facilitate its attachment to the rear of an aircraft or aircraft mounted pod.
15. An ultra wideband polarimetric synthetic aperture radar system (SAR) comprising:
a transmitter, at least one antenna, at least one coherent receiver, at least one range compression processor which creates a complex range compressed phase history signal, at least one wavelet transform processor, and at least one azimuth processor, wherein said complex range compressed phase history signal is decomposed by complex wavelet transformation into at least two spectrally distinct range compressed phase history signals and wherein at least two spectrally distinct range compressed phase history signals are then separately azimuth processed into layers of a common image, and wherein said synthetic aperture radar system may be utilized as an inverse synthetic aperture radar (ISAR).
16. The ultra wideband polarimetric synthetic aperture radar system of claim 15 wherein said spectral image layers comprise at least two octaves.
17. The ultra wideband polarimetric synthetic aperture radar system of claim 15 wherein said spectral image layers comprise at least three octaves.
18. The ultra wideband polarimetric synthetic aperture radar system of claim 15 wherein said spectral image layers comprise at least four octaves.
19. The ultra wideband polarimetric synthetic aperture radar system of claim 15 , wherein said separate spectral image layers are mapped onto a higher resolution panchromatic image layer.
20. The ultra wideband polarimetric synthetic aperture radar system of claim 15 , further comprising at least three polarimetric channels and wherein separate spectral image layers are generated for each of said at least three polarimetric channels, and wherein all of said separate spectral image layers generated for each of said at least three polarimetric channels are mapped onto a higher resolution panchromatic image layer.
21. The ultra wideband polarimetric synthetic aperture radar system of claim 15 , further comprising automatic target detection based on covariant polarimetric and spectral signatures.
22. The ultra wideband polarimetric synthetic aperture radar system of claim 15 , wherein said spectrometric inverse synthetic aperture radar utilizes an instantaneous bandwidth of at least two octaves.
23. A Synthetic Aperture Radar (SAR) in accordance with claim 15 , wherein the spectral content due to non-linear target behavior is isolated from the balance of the target spectral content.
24. The ultra wideband polarimetric synthetic aperture radar system of claim 15 , further comprising an instantaneous bandwidth of at least two octaves and using folded chirps.