Method of satellite operation using synthetic aperture radar addition holography for imaging
OwnerWilliam H. Grishaminventor
Life of this patent
Estimating the term…
Abstract
A method of satellite operation utilizing a paired-satellite configuration in which one satellite illuminates the imaged field of view and the other satellite receives the reflected energy using bistatic synthetic radar. This method enables the unambiguous detection of radar signals for imagery construction, improves stability for image quality, provides recording format linearity to minimize image reconstruction processing, provides orthogonal range-doppler pattern distribution at all points in the recording plane to minimize computer processing, provides a triangulated signal reference baseline to improve system calibratability, and enables conformal mapping and uniform sampling of zone plates to achieve three dimensional holography.
Claims13
A method for satellite based synthetic aperture radar imaging from at least two satellites, one of which is equipped with a synthetic aperture radar transmitter and another of which is equipped with a synthetic aperture radar receiver comprising:
- establishing the satellites in nominally circular and orthogonal orbits, wherein the satellites orbit at equal angular velocity with respect to the earth, and wherein the polar crossing of the first satellite is coincidental with the equatorial crossing of the second satellite, the first and the second satellites thereafter traversing equal angle displacement with respect to the polar and equatorial axes respectively;
- establishing an inter-satellite communications link for communicating data between the satellites, said data communication including coherent oscillator synchronization signals of the radar and of the communication system, and inter-satellite range and range rate data;
- maintaining the physical center line of the transmission and reception radar antennae and communication antennae on the satellites tracking dynamically in a constant angular momentum mode;
- illuminating an area of the earth with synthetic aperture radar transmission from one of the satellites;
- receiving the reflected radar signal at the other of said satellites;
- and
- recording the received synthetic aperture radar in an isometric plane, said isometric plane being parallel to the plane perpendicular to one of the eight isometric vectors, said isometric vectors having an origin at the center of the earth and being equiangular with respect to the polar and equatorial axes of the earth in one of the eight quadrants defined by the polar and equatorial axes of the earth.
A method for satellite based synthetic aperture radar imaging from at least two satellites, one of which is equipped with a synthetic aperture radar transmitter and another of which is equipped with a synthetic aperture radar receiver comprising:
- establishing said satellites in nominally circular and orthogonal orbits, wherein said satellites orbit at equal angular velocity with respect to the earth, and wherein the polar crossing of said first satellite is coincidental with the equatorial crossing of the second satellite, said first and said second satellites thereafter traversing equal angle displacement with respect to the polar and equatorial axes respectively;
- establishing an inter-satellite communications link for communicating data between said first satellite and said second satellite, said data communication including coherent oscillator synchronization signals of inter-satellite range and range rate data;
- illuminating an area of the earth with synthetic aperture radar transmission from one of said satellites and receiving the reflected radar signal at the other of said satellites;
- maintaining the physical center line of the transmission and reception radar antennae and communication antennae on said first and said second satellite tracking dynamically in a nominally constant angular momentum mode;
- and,
- adjusting the phase of the received synthetic aperture radar data to simulate recording of the data in an isometric plane, said isometric plane being parallel to the plane perpendicular to one of the eight isometric vectors having an origin at the center of the earth and being equiangular with respect to the polar and equatorial axes of the earth in each of the eight quadrants defined by the polar and equatorial axes of the earth.
Dependencies are inferred from the claim text.