Method for performing SAR acquisitions with enhanced azimuth resolution
View Patent ↗The present invention concerns a method for performing SAR acquisitions, which comprises performing, in a time division fashion, SAR acquisitions of areas of a swath of earth's surface by means of a SAR system carried by an air or space platform; wherein performing SAR acquisitions in a time division fashion includes contemporaneously acquiring, in each pulse repetition interval, a plurality of areas of the swath that are separated in azimuth; and wherein the areas acquired in T successive pulse repetition intervals form an azimuth-continuous portion of said swath, T being an integer greater than one.
1. A method for performing SAR acquisitions, comprising performing, in a time division fashion, SAR acquisitions of areas of a swath of earth's surface by means of a synthetic aperture radar system carried by an air or space platform;
characterized in that performing SAR acquisitions in a time division fashion includes contemporaneously acquiring, in each pulse repetition interval, a plurality of areas of the swath that are separated in azimuth, by:
(i) transmitting a plurality of radar signals by contemporaneously using different transmission radar beams, and receiving a plurality of backscattered radar signals by contemporaneously using different reception radar beams, wherein
(a) the transmission radar beams are angularly separated in azimuth so as to be pointed, each, at a respective one of the areas of the swath to be contemporaneously acquired, and
(b) the reception radar beams are angularly separated in azimuth so as to be pointed, each, at a respective one of the areas of the swath to be contemporaneously acquired;
wherein the transmission and reception radar beams used in T successive pulse repetition intervals form an azimuth-continuous angular span, whereby the areas acquired in T successive pulse repetition intervals form an azimuth-continuous portion of the swath, T being an integer greater than one.
2. The method of claim 1 , wherein contemporaneously acquiring, in each pulse repetition interval, a plurality of areas of the swath that are separated in azimuth includes contemporaneously acquiring, in each pulse repetition interval, P areas of the swath that are separated in azimuth, by:
transmitting a plurality of radar signals by contemporaneously using P transmission radar beams, and receiving a plurality of backscattered radar signals by contemporaneously using P reception radar beams, wherein
(a) the P transmission radar beams are angularly separated in azimuth so as to be pointed, each, at a respective one of the P areas of the swath to be contemporaneously acquired, and
(b) the P reception radar beams are angularly separated in azimuth so as to be pointed, each, at a respective one of the P areas of the swath to be contemporaneously acquired;
wherein P is an integer greater than one, and wherein the P areas of the swath separated in azimuth are acquired by using, in transmission and/or reception, an antenna of the synthetic aperture radar system partitioned into P different zones.
3. The method of claim 2 , wherein the P areas of the swath separated in azimuth are acquired by using, in transmission and/or reception, the antenna of the synthetic aperture radar system partitioned into P different zones in elevation.
4. The method according to claim 1 , wherein the SAR acquisitions are performed by using one and the same elevation pointing corresponding to the swath to be observed.
5. A synthetic aperture radar system installed on board an air or space platform and configured to carry out the method for performing SAR acquisitions as claimed in claim 1 .
6. A space platform equipped with a synthetic aperture radar system configured to carry out the method for performing SAR acquisitions as claimed in claim 1 .
7. The space platform of claim 6 , wherein said space platform is a spacecraft or a satellite.
8. An air platform equipped with a synthetic aperture radar system configured to carry out the method for performing SAR acquisitions as claimed in claim 1 .
9. The air platform of claim 8 , wherein said air platform is an aircraft, a drone or a helicopter.
10. A method for performing SAR acquisitions, comprising performing, in a time division fashion, SAR acquisitions of areas of a swath of earth's surface by means of a synthetic aperture radar system carried by an air or space platform;
characterized in that performing SAR acquisitions in a time division fashion includes contemporaneously acquiring, in each pulse repetition interval, a plurality of areas of the swath that are separated in azimuth, by:
(i) transmitting one or more radar signals by using a single transmission radar beam, and receiving a plurality of backscattered radar signals by contemporaneously using different reception radar beams, wherein
(a) the single transmission radar beam is such that to illuminate, with the transmitted radar signal(s), all the areas of the swath to be contemporaneously acquired, and
(b) the reception radar beams are narrower than said single transmission radar beam and are angularly separated in azimuth so as to be pointed, each, at a respective one of the areas of the swath to be contemporaneously acquired;
wherein the transmission and reception radar beams used in T successive pulse repetition intervals form an azimuth-continuous angular span, whereby the areas acquired in T successive pulse repetition intervals form an azimuth-continuous portion of the swath, T being an integer greater than one.