Spatio-temporal baseline and spatial coverage of lunar-based SAR repeat-track interferometry in single- and double-antenna configurations

ABSTRACT

Spatio-temporal baseline and effective spatial coverage are key parameters for lunar-based synthetic aperture radar repeat-track interferometry (LB-SAR RTI). In the mode of lunar-based single-antenna SAR RTI (LB-SASAR RTI) Earth observation, the temporal baseline and effective spatial coverage are affected by perpendicular baseline, which depends mainly on the lunar revolution. However, the moon is a nature celestial body; multiple SAR antennas can be installed on its surface to increase the potential in Earth observation. In this study, we first designed the observation geometry of lunar-based double-antenna SAR RTI (LB-DASAR RTI) and calculate its spatio-temporal baselines and effective spatial coverage. Comparing with those of the single-antenna mode, the results show that: 1) the perpendicular baselines of LB-DASAR RTI are 0–3000 km shorter than those of LB-SASAR RTI during a year, and approximate 98% of them are between 2000 and 3000 km; 2) the amount of interferometric combinations increase by about 23.5%; 3) the amount of interferometric combinations with large swath width (4400 km) is approximately doubled, resulting in an increase of 12.3% in the percentage of large swath width (4400 km); 4) the observation duration in azimuth is increased by at least 2–3 hours, equivalent to 30° to 45° of azimuthal observation range; and 5) the repeated observation frequency is higher, the most significant increase of interferometric combinations is at 40° north and south latitudes, reaching up to 286 times a year. The study is helpful for the observation mode design of LB-SAR RTI and the implementation of observation data acquisition plan.

Keywords:

• LB-SAR RTI
• single-antenna
• double-antenna
• spatio-temporal baseline
• effective spatial coverage

Acknowledgements

The authors are grateful to the support from Academician Zhou Chenghu’s team, Shandong Jianzhu University.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Key R&D Program of China under grant [2017YFA0603103], in part by the National Natural Science Foundation of China under [grant 41590854, grant 41501497 and grant 41974009], in part by the Doctoral Research Fund of Shandong Jianzhu University under grant [X20085Z0101], in part by the State Key Laboratory of Geodesy and Earth’s Dynamics (Institute of Geodesy and Geophysics, CAS) under grant [SKLGED2021-5-4], and in part by the Key Research Program of Frontier Sciences, CAS under [grant QYZDB-SSW-DQC027 and grant QYZDJ-SSW-DQC042].