초록 ▼

Signal processing methods useful in single-antenna multiple-pass interferometric synthetic aperture radars. The signal processing methods compute an initial elevation estimate from the phase difference between a pair of images (A0,A1) with a relatively small elevation angle difference (i.e., a short

Signal processing methods useful in single-antenna multiple-pass interferometric synthetic aperture radars. The signal processing methods compute an initial elevation estimate from the phase difference between a pair of images (A0,A1) with a relatively small elevation angle difference (i.e., a short interferometric baseline) and uses it to initialize the elevation estimation process for pairs of images (A0,A2) with longer interferometric baselines. The method may be used to process images that are coherent, or not necessarily mutually coherent. The outputs of the methods comprise a terrain elevation map that mitigates for atmospheric error and a turbulence map.

대표청구항 ▼

1. A signal processing method for use with a single antenna, multi-pass synthetic aperture radar (SAR), said method comprising the steps of: processing raw synthetic aperture radar data to produce a plurality of complex synthetic aperture radar images therefrom; processing the complex synthetic

1. A signal processing method for use with a single antenna, multi-pass synthetic aperture radar (SAR), said method comprising the steps of: processing raw synthetic aperture radar data to produce a plurality of complex synthetic aperture radar images therefrom; processing the complex synthetic aperture radar images to produce a plurality of linear phase matched complex synthetic aperture radar images; and processing the plurality of linear phase matched complex synthetic aperture radar images to produce a terrain elevation map, a coregistered SAR image, and a map of atmospheric inhomogeneities. 2. The method of claim 1 wherein the plurality of linear phase matched complex images comprises three coherent images, and wherein the step of processing the three coherent images comprises the steps of: computing first and second complex interferograms derived from the three coherent images; processing the respective complex interferograms using first and second filters; unwrapping the phase of the image output by the first filter to produce a real-valued reference phase image; scaling the real-valued reference phase image by the baseline ratio; removing the phase reference function from the complex interferogram output by the second filter; processing the output image produced by the remove phase reference function to unwrap the phase thereof to produce a real-valued phase image; and adding the phase images output from the scale by baseline ratio step and the unwrap phase step to produce a terrain elevation map. 3. The method of claim 2 that further comprises the steps of: filtering the output image produced by the remove phase reference function using a complex Weiner filter to produce a filtered complex interferogram; and processing the filtered complex interferogram to unwrap the phase thereof and produce a real-valued phase image comprising an atmospheric turbulence map. 4. The method of claim 1 wherein the plurality of linear phase matched complex images comprises four images that are not necessarily mutually coherent, and wherein the step of processing the four coherent images comprises the steps of: computing first and second complex interferograms derived from selected pairs of the coherent images; processing the respective complex interferograms using first and second filters; unwrapping the phase of the image output by the first filter to produce a real-valued reference phase image; scaling the real-valued reference phase image by the baseline ratio; removing the phase reference function from the complex interferogram output by the second filter; processing the output image produced by the remove phase reference function to unwrap the phase thereof to produce a real-valued phase image; and adding the phase images output from the scale by baseline ratio step and the unwrap phase step to produce a terrain elevation map. 5. The method of claim 2 that further comprises the steps of: filtering the output image produced by the remove phase reference function using a complex Weiner filter to produce a filtered complex interferogram; and processing the filtered complex interferogram to unwrap the phase thereof and produce a real-valued phase image comprising an atmospheric turbulence map.