Cluster unmanned aerial vehicle synthetic aperture radar high-frame-rate imaging method

Abstract

The invention discloses a cluster unmanned aerial vehicle synthetic aperture radar high-frame-rate imaging method. The method comprises steps of firstly defining an echo collected by each unmanned aerial vehicle system as a subsystem echo in an echo recording process according to the characteristics of a cluster unmanned platform radar echo signal and a time domain back projection imaging method; performing pulse compression on each subsystem echo; then calculating the overlapping condition between the spatial spectrums of the subsystems to obtain the repetition degree of the subsystems, and carrying out undistorted weighting on the data of the overlapping part between the subsystems to ensure relatively high imaging quality; and determining the size of an imaging grid according to the resolution capability of each subsystem, obtaining a coarse image of each subsystem by using a time domain back projection method, carrying out layer-by-layer iteration, and carrying out coherent fusion on the images of the subsystems till a high-resolution imaging result of the whole system is obtained. The method provided by the invention overcomes the limitation of long mechanical time consumption caused by the whole long aperture of the traditional single platform movement, and gives consideration to higher true frame rate and farther observation distance.

Description

technical field [0001] The invention belongs to the technical field of radar imaging, and in particular relates to a synthetic aperture radar high frame rate imaging technology for a cluster unmanned aerial vehicle platform. Background technique [0002] Synthetic Aperture Radar (SAR) is widely used in terrain surveying and mapping, disaster rescue, marine monitoring and battlefield situational awareness due to its significant advantages such as all-day, all-weather, and high-resolution. SAR high frame rate imaging technology presents the dynamic information of the observed scene in the form of visual active images that are conducive to intuitive interpretation by the human eye, and can continuously record the dynamic changes of the target area with high resolution, which is conducive to the realization of real-time monitoring of vehicles, ships and other places on the sea surface. Dynamic and continuous monitoring of sensitive targets. [0003] SAR image frame rate can be ...

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Problems solved by technology

Therefore, to achieve "large aperture" high-resolution and high frame rate imaging on a single platform, it is limited by platform speed and wavelength.

[0004] In order to improve the imaging frame rate, the literature "L.Wells, K.Sorensen, A.Doerry, et al.Developments in SAR and IFSAR systems and technologies at sandia national laboratories[C].Proc.IEEE Aerospace Conference,2005,2:1085– 1095" uses overlapping sub-aperture processing to increase the image frame rate, but the image frame rate is a false frame rate, and the true frame rate of imaging is still limited by the wavelength; the literature "B Zhang, Y.Pi, J.Li.Terahertz imaging radar with inverse aperture synthesis techniques:system structure,signal processing,and experiment results[J].IEEE SensorsJournal,2015,15(1):290-299."Using terahertz SAR imaging technology to achieve high frame rate imaging, but its wavelength is extremely short , the attenuation is serious in the atmospheric environment, the effective detection distance is short, and it is not suitable for long-distance observation

The existing technology cannot take into account the high "true frame rate" and the long observation distance

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