Patent ID: 6879279

Claim:
An imaging method from a moving platform, comprising: illuminating an object with an electromagnetic radiation source directed from an aperture, collecting a reflected radiation from the object by a first sub-aperture and a second sub-aperture, each having an effective width that is less than about the width of the aperture, for a plurality of platform positions, measuring a plurality of differential phases from the reflected radiation collected by the sub-apertures to produce a plurality of resultant (N) phases for each of the platform positions, wherein an image having a spatial resolution corresponding to a synthetic aperture is constructed from the resultant (N) phases, optically splitting the collected radiation by the first sub-aperture into a first and a second optical beam and optically splitting the collected radiation by the second sub-aperture into a third and a fourth optical beam, collecting the first and the second optical beams by an adapted first pair of high speed heterodyne detectors and collecting the third and the fourth optical beams by an adapted second pair of high speed heterodyne detectors, generating a pair of common in-phase (I) local oscillator reference beams and a pair of common quadrature (Q) local oscillator reference beams, mixing the first and the second collected optical beams with an I and a Q beam on a pair of adapted first high speed heterodyne detectors and mixing the third and the fourth collected optical beams with an I and a Q beam on a second pair of adapted high speed heterodyne detectors, processing the heterodyned signals to produce a first phase φm j and a second phase φm j+1 with respect to the common local oscillator such that a measured phase differential φm j+1 −φm j between the sub-apertures is capable of being produced, calculating the resultant (N) phases by summing the phase differentials at each of the platform positions according to [φ j+1 =φ j +(φm j+1 −φm j )]; and processing the resultant (N) phases to produce an image having a spatial resolution corresponding to a synthetic aperture of about N(the effective width/4).