Method for establishing platform-based maneuvering bistatic SAR echo model in pulse propagation time

Abstract

The invention discloses a method for establishing a platform-based maneuvering bistatic SAR echo model in the pulse propagation time, aiming at the problem that all current echo models for single-baseSAR and bistatic SARs of mobile platforms are based on the "stop-run-stop" hypothesis, which causes considerable propagation delay error and azimuth quadratic phase error. The invention considers themaneuverability of the platform during the pulse propagation process, and corrects a traditional pulse propagation delay equation based on the "stop-run-stop" hypothesis, thereby establishing an accurate pulse propagation delay equation. An approximate solution of the receiving station distance historical high-order term is found to solve the high-precision approximate analytical expression of the exact pulse propagation delay equation solution. Then, a first-order Taylor expansion is performed on a high-precision approximate analytical expression for fast time, and finally a high-precision bistatic SAR echo model can be established, which can be applied to various bistatic SAR cases.

Description

technical field [0001] The invention belongs to the field of synthetic aperture radar (Synthetic Aperture Radar, SAR) imaging technology, in particular to an echo model building technology. Background technique [0002] SAR has special all-weather and all-weather high-resolution imaging capabilities. More and more emerging high maneuvering platforms (high maneuvering platform, HMP) such as unmanned aerial vehicles and hypersonic vehicles hope to improve their environmental awareness by carrying SAR. The echo model plays a key role in the data processing of SAR. [0003] The "stop-and-go" assumption is currently widely used in echo modeling. But it is not effective in some types of systems, such as many emerging SAR systems with high resolution or high speed. [0004] In order to solve this problem, some literatures have proposed some improved echo models that do not rely on the "stop-stop" assumption. For example, based on the assumption of uniform linear motion, the docu...

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Problems solved by technology

However, due to their inherent assumptions, such as uniform rectilinear or satellite orbital motion, these existing echo models cannot be applied to the general case with maneuvering (i.e. non-uniform rectilinear motion, which is the case in circular SAR, maneuvering platform SAR, etc. very common) and bistatic configuration; literature "Fully polarimetric high-resolution 3-D imaging with circular SAR at L-Band, IEEE Trans. Geosci. Remote Sens., vol.52, no.6, pp.3074– 3090, Jun.2014", the literature "Feature-independent aperture evaluator for the curvilinear SAR, IEEE Geosci.Remote Sens. Lett., vol.4, no.2, pp.191–195, Apr.2007" and the literature "Acceleration model analyzes and imaging algorithm for highly squintedairborne spotlight mode SAR with maneuvers,IEEE J.Sel.Topics Appl.EarthObserv.in Remote Sens.,vol.8,no.3,pp.1120–1131,Mar.2015" using bistatic structure The echo acquisition geometric model of the motorized platform (which can flexibly change the magnitude or direction of the velocity) of the mobile platform configuration (the configuration of a single base station can be regarded as a special case of the configuration of a bistatic configuration) can be applied to circular motion, curved motion or maneuvering SAR Wait

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