{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T01:20:34Z","timestamp":1760232034322,"version":"build-2065373602"},"reference-count":28,"publisher":"MDPI AG","issue":"20","license":[{"start":{"date-parts":[[2022,10,12]],"date-time":"2022-10-12T00:00:00Z","timestamp":1665532800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Project of Stable Support for Youth Team in Basic Research Field, CAS","award":["YSBR-018","XDB41000000","41427901"],"award-info":[{"award-number":["YSBR-018","XDB41000000","41427901"]}]},{"name":"B-type Strategic Priority Program of CAS","award":["YSBR-018","XDB41000000","41427901"],"award-info":[{"award-number":["YSBR-018","XDB41000000","41427901"]}]},{"name":"National Natural Science Foundation of China","award":["YSBR-018","XDB41000000","41427901"],"award-info":[{"award-number":["YSBR-018","XDB41000000","41427901"]}]},{"name":"Meridian Project","award":["YSBR-018","XDB41000000","41427901"],"award-info":[{"award-number":["YSBR-018","XDB41000000","41427901"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Space objects around the Earth are a potential pollution source for ground-based radio observations. The Sanya incoherent scatter radar (SYISR) is a newly built active digital phased array, all solid-state transmitting and digital receiving incoherent scatter radar in Sanya (18.3\u00b0N, 109.6\u00b0E), with the main purpose of ionospheric monitoring and investigations. In this study, we presented the effect of the greatly increased number of space objects on ionospheric observations through SYISR. Firstly, we showed the space object pollution on the range-time-intensity (RTI), autocorrelation function (ACF)\/power spectra, and ionosphere parameter of SYISR measurements. An altitude of around 600 km is the region where space objects occur most frequently. Then, we eliminated the space object pollution using the traditional smallest of constant-false-alarm-rate (SO-CFAR) algorithm. However, pollution from smaller space objects remains, whose reflected echo is comparable to or lower than the background ionosphere, which results in unrealistic retrieved ionospheric electron density. Furthermore, we quantitatively assessed the space object effect based on the current space object orbit database and simulation. The pollution should linearly increase with the increase in the number of space objects in the future. Among the space objects, whose radar cross section (RCS) and orbit information are now published, there still exist ~9000 (~37% of the total number) space objects, whose effect is difficult to eliminate. This study is beneficial to the data process of SYISR and has implications for similar types of ionospheric observations by radar.<\/jats:p>","DOI":"10.3390\/rs14205092","type":"journal-article","created":{"date-parts":[[2022,10,12]],"date-time":"2022-10-12T22:45:29Z","timestamp":1665614729000},"page":"5092","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["The Effect of Space Objects on Ionospheric Observations: Perspective of SYISR"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9914-7157","authenticated-orcid":false,"given":"Junyi","family":"Wang","sequence":"first","affiliation":[{"name":"Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China"},{"name":"College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China"},{"name":"Beijing National Observatory of Space Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3379-9392","authenticated-orcid":false,"given":"Xinan","family":"Yue","sequence":"additional","affiliation":[{"name":"Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China"},{"name":"College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China"},{"name":"Beijing National Observatory of Space Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China"}]},{"given":"Feng","family":"Ding","sequence":"additional","affiliation":[{"name":"Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China"},{"name":"College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China"},{"name":"Beijing National Observatory of Space Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China"}]},{"given":"Baiqi","family":"Ning","sequence":"additional","affiliation":[{"name":"Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China"},{"name":"Beijing National Observatory of Space Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China"}]},{"given":"Lin","family":"Jin","sequence":"additional","affiliation":[{"name":"Nanjing Research Institute of Electronics Technology, Nanjing 210039, China"}]},{"given":"Changhai","family":"Ke","sequence":"additional","affiliation":[{"name":"Nanjing Research Institute of Electronics Technology, Nanjing 210039, China"}]},{"given":"Ning","family":"Zhang","sequence":"additional","affiliation":[{"name":"Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China"},{"name":"Beijing National Observatory of Space Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China"}]},{"given":"Junhao","family":"Luo","sequence":"additional","affiliation":[{"name":"Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China"},{"name":"Beijing National Observatory of Space Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8335-0334","authenticated-orcid":false,"given":"Yonghui","family":"Wang","sequence":"additional","affiliation":[{"name":"Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China"},{"name":"College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China"},{"name":"Beijing National Observatory of Space Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China"}]},{"given":"Hanlin","family":"Yin","sequence":"additional","affiliation":[{"name":"Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China"},{"name":"College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China"},{"name":"Beijing National Observatory of Space Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0150-4692","authenticated-orcid":false,"given":"Mingyuan","family":"Li","sequence":"additional","affiliation":[{"name":"Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China"},{"name":"College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China"},{"name":"Beijing National Observatory of Space Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4390-6895","authenticated-orcid":false,"given":"Yihui","family":"Cai","sequence":"additional","affiliation":[{"name":"Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China"},{"name":"College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China"},{"name":"Beijing National Observatory of Space Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, 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