Bistatic synthetic aperture radar (SAR) imaging method based on optimal image space

Abstract

The invention discloses a bistatic synthetic aperture radar (SAR) imaging method based on an optimal image space. The bistatic SAR imaging method based on the optimal image space is used for solving the problem that no unified bistatic SAR projection relationships for shift-variant bistatic SAR exist nowadays due to the relatively-complex spatial geometrical configuration and range historic two-dimensional space-variant characteristics of the shift-variant bistatic SAR. According to the bistatic SAR imaging method, the optimal projection vector is obtained through calculation, echo signals of the bistatic SAR are mapped to a projection space by using two-dimensional non-uniform fast Fourier transform, the focusing processing is carried out, and then, the optimal imaging result under action of mean square is obtained. Compared with the existing bistatic SAR imaging method, the bistatic SAR imaging method disclosed by the invention has the advantage that the statistically-optimal focusing performance can be obtained.

Description

technical field [0001] The invention belongs to the field of radar technology, and in particular relates to the imaging technology of bistatic synthetic aperture radar (abbreviated as bistatic SAR). Background technique [0002] Bistatic SAR refers to the SAR system in which the radar transmitter and receiver are separated on two different moving platforms. Due to the separation of the transmitting platform and the receiving platform of the bistatic SAR system, compared with the traditional single-static SAR, the platform relationship is more flexible, and it has more abundant space and motion resources. It can not only realize the imaging function of traditional single-station SAR, but also has the following advantages: [0003] 1. The imaging area is flexible. The imaging area of ​​traditional monostatic SAR is usually in the side-view direction of the platform movement direction; while bistatic SAR forms a different spatial position relationship with the imaging area th...

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Problems solved by technology

[0007] 1. The distance history of bistatic SAR is the sum of the distance histories of transmitter and receiver, which has the form of a double root sign. It is impossible to solve the analytical expression of the two-dimensional spectrum of bistatic SAR by directly using the principle of stationary phase. research brings difficulties

[0008] 2. The shift characteristic of bistatic SAR makes the distance migration of point targets have two-dimensional space variability, making it difficult to design an efficient and practical imaging algorithm

However, due to its relatively complex spatial geometry and the two-dimensional space-varying characteristics of distance history, there is no unified image coordinate system for bistatic SAR.

So far, no special research has been done on the selection of bistatic SAR projection space

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