Super‐resolution forward‐looking imaging method for manoeuvering platform with optimised dictionary and extended sparsity adaptive matching pursuit

Abstract

In forward‐looking imaging, left‐right Doppler is ambiguous and cross‐range resolution is limited by real aperture, which result in traditional synthetic aperture radar imaging methods no longer applicable. Besides, the impact of three‐dimensional acceleration on an over‐complete dictionary matrix and sparse reconstruction kernel is not considered in conventional super‐resolution forward‐looking imaging methods. To solve these problems, a super‐resolution forward‐looking imaging method for manoeuvering platforms is proposed. First, the range walk caused by forward‐looking geometry and higher‐order phase introduced by three‐dimensional acceleration are eliminated by compensating a pre‐processing function. Subsequently, according to beam steering‐based geometry and linear regression model, the over‐complete dictionary matrix is optimised to more accurately describe the complicated forward‐looking geometry with curved trajectory. Finally, sparsity adaptive matching pursuit kernel with an improved halting condition is adopted to reconstruct the forward‐looking scene. The proposed method is supported by point target simulation and surface target simulation.

Radar Forward-Looking Super-Resolution Imaging Using a Two-Step Regularization Strategy

“…exp(−j2πf c τ d ) is the Doppler shift. For an airborne RAR system, after pulse compression and range walk correction processing [43], [44], the received echo can be expressed as…”

Airborne forward‐looking radar imaging approach via modified propagator method in planar phased array

“…Forward-looking radar imaging can image the forward-looking area with a high resolution, which can be widely applied to military and civilian fields such as precision guidance, remote sensing mapping, automatic driving etc [1][2][3][4][5][6][7][8][9]. For traditional synthetic aperture radar (SAR) imaging techniques, there exists a significant coupling between azimuth and range dimensions in forward-looking scenarios.…”

“…In recent years, researchers have carried out a lot of research on forward-looking radar imaging algorithms. The main algorithms include monopulse radar forward-looking imaging (FLMC) [5][6][7][8], scanning radar deconvolution FLMC [9][10][11][12][13], bistatic forward-looking SAR (BFSAR) imaging [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29], sector imaging radar for enhanced vision (SIREV) [30][31][32][33][34] and multi-channel FLMC algorithms [35][36][37][38][39][40][41][42][43].…”

Real Aperture Radar Super-Resolution Imaging for Sea Surface Monitoring Based on a Hybrid Model

“…This approach is often referred to as a super-resolution technique. In recent years, researchers have increasingly employed this technology to enhance the resolution of RASR [6][7][8][9][10][11].…”