Cosine Matching Imaging Method for Rotating Scanning Synthesis Aperture Imaging Radiometer

Jianfei Chen,Xiaowei Zhu,Yuanjiang Li,Sheng Zhang

doi:10.1155/2018/7482753

Abstract

Millimeter-wave synthesis aperture imaging radiometer (SAIR) can realize high-resolution observations without requiring the real large aperture antenna. Among the SAIRs, the Rotating Scanning SAIR (RS-SAIR) with linear sparse array is a popular system with low redundancy and high reliability. However, due to the lack of matched imaging methods, its imaging precision is usually low. For improving its imaging precision, a novel Cosine Matching Imaging (CMI) method is proposed in this paper. In CMI method, according to the characteristic of rotating projection imaging, the angle-orientation image is constituted by the 1D projection images measured by RS-SAIR in a series of angles firstly. Then, according to the trajectory of the target in angle-orientation image, the pixel values of the brightness temperature image are extracted by cosine matching method from the angle-orientation image one by one. The simulation results demonstrate that the proposed CMI imaging method has higher reconstruction accuracy for the RS-SAIR.

Highlights

Millimeter-wave synthesis aperture imaging radiometers (SAIR) are powerful sensors for high-resolution observations in various fields [1,2,3]
For improving the imaging precision of Rotating Scanning SAIR (RS-SAIR) further, we study the synthesis aperture projection imaging principle deeply and find that the trajectory of targets in angle-orientation image meets cosine distribution
In order to simulate RS-SAIR imaging process accurately, the received signals of antennas are obtained by integral operation of the radiation waves generated by all discrete sources, and the visibility samples are calculated by cross-correlated calculation between antennas

Summary

Introduction

Millimeter-wave synthesis aperture imaging radiometers (SAIR) are powerful sensors for high-resolution observations in various fields [1,2,3]. Each complex correlation of pairwise antennas is a sample of visibility function, which can be utilized to reconstruct the brightness temperature image of the target scene. The antenna array configuration is an extremely important component for the SAIR It directly defines the distribution of the visibility samples and further affects the imaging performance of SAIR system. For improving the imaging precision of RS-SAIR further, we study the synthesis aperture projection imaging principle deeply and find that the trajectory of targets in angle-orientation image meets cosine distribution Based on this fact, a novel Cosine Matching Imaging (CMI) algorithm based on the CLEAN idea is proposed in this paper. In CMI method, the 1D projection images of 2D target scene are measured by the RS-SAIR with linear sparse array in a series of angles firstly. Its imaging accuracies is better than the BP method under the same conditions

The Basic Synthesis Aperture Imaging Theory

Description of CMI Method for RS-SAIR

Simulation Experiments and Results

NUFT-method

Conclusion