Radio Frequency Camera: A Noncoherent Circular Array SAR With Uncoordinated Illuminations

• Published in: IEEE transactions on geoscience and remote sensing Vol. 60; pp. 1 - 14
• Main Authors: Huang, Xiaojing, Nan, Yijiang, Guo, Y. Jay
• Format: Journal Article
• Language: English
• Published: New York IEEE 2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; and synthetic aperture radar (SAR); Cameras; Illumination; Illuminators; Image processing; Image reconstruction; Imaging; Imaging techniques; Information processing; Lighting; Microwave antenna arrays; Microwave imaging; millimeter wave; Millimeter waves; Optical properties; Radar arrays; Radar imaging; Radio; Radio frequency; radio frequency (RF); Reference signals; SAR (radar); Signal processing; Synthetic aperture radar; Wave frequency; Waveforms
• ISSN: 0196-2892; 1558-0644
• DOI: 10.1109/TGRS.2022.3157864

A novel noncoherent microwave imaging principle with periodical or random radio frequency (RF) illumination is proposed in this article. Implemented with circular array synthetic aperture radar (SAR) frontend and low-complexity signal processing algorithms, the imaging device, called RF camera, achieves some desired properties similar to an optical camera, such as the capability to operate with multiple uncoordinated illuminators. Different from conventional multistatic imaging, the RF camera does not require any knowledge about an illuminator's location or signal waveform. A static illumination sensor (IS) can be used to provide a reference signal for image reconstruction. With periodical illumination, the RF camera can even operate without IS, but the imaging performance can be improved with IS. With random illumination, the IS is necessary for the RF camera operation, and the imaging distortion can be described by a point blur function. Theoretical analyses on the imaging signal-to-noise ratios are performed under different RF camera operation modes. Simulation and experimental tests are conducted using 77-GHz millimeter wave frequency to verify the noncoherent imaging principle and its performance.