Abstract
Raw data simulation is the front-end work of synthetic aperture radar (SAR), which is of great significance. For high-squint spotlight SAR, the frequency domain simulation algorithm is invalid because of the range-azimuth coupling effect. In order to realize high-squint spotlight SAR raw data simulation in the frequency domain, an algorithm based on coordinate transformation and non-uniform fast Fourier transform (NUFFT) is proposed. This algorithm generates broadside raw data using a two-dimensional (2-D) frequency simulation algorithm; then, coordinate transformation is used by analyzing the characteristics of broadside and high-squint spotlight SAR. After coordinate transformation, NUFFT is carried out to realize the coupling relation in the 2-D frequency domain. Since the coordinate transformation ignores the influence of range walk, the range walk is compensated after NUFFT. As a result, compared with the traditional squint spotlight SAR frequency domain simulation algorithm, the proposed algorithm can improve the accuracy of point and distributed target imaging results, and the efficiency of the proposed algorithm can be significantly improved in contrast the traditional time domain algorithm.
Highlights
Synthetic aperture radar (SAR) is an active imaging technology, based on microwaves, which has the ability to observe the Earth, all day and during all weathers
In order to solve the problem that the frequency domain raw data simulation algorithm is invalid in the case of high-squint synthetic aperture radar (SAR), an algorithm based on coordinate transformation and non-uniform fast Fourier transform (NUFFT) was proposed
Other time domain acceleration algorithms proposed by some researchers require a high-performance central processing unit (CPU) and graphics processing unit (GPU), for example, the algorithms in [17,18,19,20,21] require a powerful CPU and GPU for acceleration
Summary
Synthetic aperture radar (SAR) is an active imaging technology, based on microwaves, which has the ability to observe the Earth, all day and during all weathers. SAR can be operated in a number of different modes, such as stripmap, spotlight, scan and terrain observation by progressive scan (TOPS) [1,2,3,4,5,6,7]. For the spotlight SAR mode, it steers the beam over the full acquisition time to illuminate the same area (a spot on the ground), so as to improve the azimuth resolution. Due to the mobility of SAR platforms, a high or low squint angle always exists [8,9]. Squint spotlight SAR has been widely used in high-resolution
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