Abstract
Free of the constraints of orbit mechanisms, weather conditions and minimum antenna area, synthetic aperture radar (SAR) equipped on near-space platform is more suitable for sustained large-scene imaging compared with the spaceborne and airborne counterparts. Terrain observation by progressive scans (TOPS), which is a novel wide-swath imaging mode and allows the beam of SAR to scan along the azimuth, can reduce the time of echo acquisition for large scene. Thus, near-space TOPS-mode SAR (NS-TOPSAR) provides a new opportunity for sustained large-scene imaging. An efficient full-aperture imaging scheme for NS-TOPSAR is proposed in this paper. In this scheme, firstly, two-step processing (TSP) is adopted to eliminate the Doppler aliasing of the echo. Then, the data is focused in two-dimensional frequency domain (FD) based on Stolt interpolation. Finally, a modified TSP (MTSP) is performed to remove the azimuth aliasing. Simulations are presented to demonstrate the validity of the proposed imaging scheme for near-space large-scene imaging application.
Highlights
Near space is defined as the atmospheric region from about 20 km to 100 km above the Earth’s sea level, which is usually not accessible to satellites or conventional maneuvering aircrafts [1]
Synthetic aperture radar (SAR) equipped on near-space platform, which is free of the constraints of the orbit mechanism and weather conditions, has drawn widespread attention for its unique capabilities such as short revisiting cycle compared with spaceborne SAR, and sustained large-scene imaging compared with airborne SAR [2,3,4,5,6,7,8]
Inspired by the above-mentioned two-step processing (TSP), which is adopted to eliminate the Doppler aliasing of the raw data of NS-TOPSAR, we propose a modified TSP (MTSP) to eliminate the azimuth folding of the resulted signal of Part B
Summary
Near space is defined as the atmospheric region from about 20 km to 100 km above the Earth’s sea level, which is usually not accessible to satellites or conventional maneuvering aircrafts [1]. Guang-Cai Sun et al [24] proposed a chirp scaling algorithm (CSA) based on two-step processing (TSP, originally proposed in [25] to process Spotlight SAR data) and SPECtral ANalysis (SPECAN) [26] In this scheme, TSP is adopted to transform the aliasing from the Doppler domain to the azimuth TD, the CSA (without azimuth compression) is conducted to perform range compression, second range compression (SRC) and range cell migration correction (RCMC). ECSA based on chirp-z transform (CZT) and baseband azimuth scaling (BAS) algorithm They share the same preprocessing method (i.e., TSP) to eliminate the Doppler aliasing of the raw data and CSA to perform range compression, SRC and RCMC.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
