Optimal Design of the Reflector Antenna to Improve Performance of C-Band Quad-Pol ScanSAR Systems

Abstract

The performance of synthetic aperture radar (SAR) antenna determines the quality of images obtained from the spaceborne SAR system, and thus, SAR antenna should be designed to satisfy the target performance of SAR system. The performance indicators of a SAR system, such as ambiguity-to-signal ratio and resolution, also depend on the SAR operation mode. Therefore, it is important to consider the operation mode when designing an SAR antenna. In this paper, we analyzed the SAR antenna’s effect on ScanSAR (scanning synthetic aperture radar) which is a representative wide-swath mode and its quadrature-polarimetric (quad-pol) mode. In addition, we confirmed that the optimal reflector antenna for the C-band quad-pol ScanSAR system can be designed by analyzing the relation between the antenna size and the system performance.

WITHDRAWN: Optical Satellite Sensor and Positioning Accuracy Assessment for The Hongqi-H9 Wide-Range Satellite in Different Terrains

“…The sensor information for the Jilin-1KF01A satellite is presented in Table 1 [11]. In general, the resolution and swath width of satellite images are inversely related, that is, the swath width decreases as the resolution increases [12]. Conventionally, the satellite swath width is increased by stitching multiple lenses whose optical axis does not point to the center of the Earth [9].…”

Performance Evaluation of a Modified SweepSAR Mode for Quad-Pol Application in SAR Systems

“…Therefore, if the requirements change, the antenna size, which determines the achievable range of the SAR system performance, should be changed. As a result of confirming the performance changes derived from the size of the reflector antenna in each operation mode, increasing the reflector size for the ScanSAR improves the ambiguity performance but worsens the resolution [20]. Conversely, SweepSAR and M-SweepSAR have the advantage of maintaining resolution in comparison with ScanSAR even when the reflector size increases, and M-SweepSAR can reduce the reflector size in comparison with SweepSAR, as mentioned in Chapter II.…”

“…However, as the reflector width increases, the space between the feeds becomes narrower and the minimum space is limited by the size of the feed antenna. Therefore, RASR and AASR require an increase in the reflector size, but the resolution and the size of the feed antenna must be considered as the upper bound of the reflector width [13,20].…”

Cross-Pol Pattern Effects of Parabolic Reflector Antennas on the Performance of Spaceborne Quad-Pol SAR Systems

“…System performance indicators related to SAR images include noise equivalent sigma zero (NESZ), resolution, and swath width. These performance indicators mainly consider the effects of the main beam of antenna radiation patterns, whereas the ambiguity ratios consider the overall shape of antenna radiation patterns, including sidelodes, so the ambiguity ratio is an important performance indicator that should be analyzed in SAR antenna design and optimization [14,15]. If the ambiguity performance is not good enough, the signals coming into the sidelobes (i.e., the ambiguous signals) will result in artificial targets in the SAR image.…”

“…In addition, as the antenna size increases, the ambiguity performance improves, but the resolution and swath width tend to be opposite. Therefore, it is necessary to select an optimal antenna size and system parameters to take this into account [15]. Cross ambiguity is a compound of the causes of range ambiguity and azimuth ambiguity, and accordingly, elevation and azimuth angles to the antenna boresight angle must be considered simultaneously.…”