Improving the Compensation of Platform Movements in Synthetic Aperture Radar using Improved Back Projection algorithm based on INS and GPS data

Document Type : Original Article

Authors

1 Faculty of Electrical Engineering - Imam Hossein University

2 Faculty of Electrical Engineering, University of Imam Hossein

Abstract

One of the suitable tools for forming aerial images is the use of Synthetic Aperture Radar with processing capabilities in range and direction. These types of radars are needed to high resolution in the azimuth and range. SAR imaging algorithms in Frequency domain form a two-dimensional image by compressing radar signals in the direction of the range and Azimuth, and due to the use of a matched filter in the frequency domain, they have low cost computational. Instead, they face limitations such as the complexity of the range Doppler algorithm at high tilt angles, the limitation of using the Chirp scaling algorithm in tensile processing, compensation of range cell migration, etc. In the time domain, two Time Domain Correlation algorithms (TDC) and Back-Projection Algorithm (BPA) use the mutual correlation of the received signal and the reference signal for the range and azimuth of the target image. The Back-Projection algorithm uses batch processing of targets, compared to the time domain correlation algorithm, which is pixel-by-pixel processing, and has a lower computational cost. For some imaging modes that require a high tilt angle, due to the nonlinear range equation of this type of radar system, the use of any kind of approximation in this equation is not allowed. In this paper, good results were obtained by proposing an improved Back-Projection (Imp-BP) algorithm and appropriate compensation. By examining the simulated results in 4 different modes, it was shown that the Imp-BP algorithm has improved the resolution and PSLR by about 40%.

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