Method for 3-D SAR wavenumber domain fast imaging

Abstract

The invention provides a method for 3-D SAR wavenumber domain fast imaging. The method just reestablishes area of interest but not a whole three-dimensional observation area scene, thereby preventing sharp increase of data size, and fast imaging process can be performed.

Description

technical field [0001] The invention relates to the technical field of radar imaging and signal processing, in particular to a 3-D SAR under the condition that the length of the cross-course aperture is much smaller than the cross-course surveying and mapping bandwidth in the airborne downward-looking array 3-DSAR and multi-baseline 3-D SAR working modes A method for fast imaging in the wavenumber domain. Background technique [0002] Airborne array down-looking 3-D SAR and multi-baseline 3-D SAR can obtain the three-dimensional scattering information of the scene in the observation area, and can overcome the problems of shadows and overlapping in conventional side-looking SAR, so they have broad application prospects. At present, the 3-D SAR imaging processing mainly uses RD, CS, ω-k and other methods in the conventional side-looking SAR imaging processing methods in the wave propagation direction and track direction, and then uses SPECAN, beamforming, methods such as comp...

AI Technical Summary

Problems solved by technology

Since the higher-order items of the third and higher orders in the distance history are ignored, the three-dimensional observation area scene cannot be accurately reconstructed, especially when the distance from the radar to the observation area is short and the survey area of ​​the observation area is large, the approximation of the distance history resulting in a larger reconstruction error

[0003] The three-dimensional wavenumber domain method can fully compensate the distance migration in the scene, and the reconstruction accuracy is high, but this type of method requires that the synthetic aperture length is not less than the imaging area when collecting echoes to prevent FFT from wrapping. In SAR, the length of the cross-course array antenna is generally several meters, and the cross-course width is several hundred meters to several thousand meters. Therefore, a large amount of zero padding is required for the echo data, which will bring a surge in memory requirements and calculations.

If the three-dimensional wavenumber domain method is directly used to reconstruct the scene of the entire observation area, both the amount of data and the amount of calculation are very large, which limits the application of this method in the airborne downward-looking array 3-D SAR

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