Universitat Politècnica de Catalunya. Departament de Teoria del Senyal i Comunicacions, Universitat Politècnica de Catalunya. CommSensLab-UPC - Centre Específic de Recerca en Comunicació i Detecció UPC, Jin, Shuanggen, Camps Carmona, Adriano José, Jia, Yan, Wang, Feng, Martín Neira, Manuel, Huang, Feixiong, Yan, Qingyun, Zhang, Shuangcheng, Li, Zhongyu, Edokossi, Komi, Yang, Dongkai, Xiao, Zhiyu, Ma, Zhongmin, Bai, Weihua, Universitat Politècnica de Catalunya. Departament de Teoria del Senyal i Comunicacions, Universitat Politècnica de Catalunya. CommSensLab-UPC - Centre Específic de Recerca en Comunicació i Detecció UPC, Jin, Shuanggen, Camps Carmona, Adriano José, Jia, Yan, Wang, Feng, Martín Neira, Manuel, Huang, Feixiong, Yan, Qingyun, Zhang, Shuangcheng, Li, Zhongyu, Edokossi, Komi, Yang, Dongkai, Xiao, Zhiyu, Ma, Zhongmin, and Bai, Weihua
The Global Navigation Satellite Systems (GNSS), including the US’s GPS, China’s BDS, the European Union’s Galileo, and Russia’s GLONASS, offer real-time, all-weather, any-time, anywhere and high precision observations by transmitting L band signals continuously, which have been widely used for positioning, navigation and timing. With the development of GNSS technology, it has been found that GNSS-reflected signals can be used to detect Earth’s surface characteristics together with other signals of opportunity. In this paper, the current status and latest advances are presented on Global Navigation Satellite System-Reflectometry (GNSS-R) in theory, methods, techniques and observations. New developments and progresses in GNSS-R instruments, theoretical modeling, and signal processing, ground and space-/air-borne experiments, parameters retrieval (e.g. wind speed, sea surface height, soil moisture, ice thickness), sea surface altimetry and applications in the atmosphere, oceans, land, vegetation, and cryosphere are given and reviewed in details. Meanwhile, the challenges in the GNSS-R development of each field are also given. Finally, the future applications and prospects of GNSS-R are discussed, including multi-GNSS reflectometry, new GNSS-R receivers, GNSS-R missions, and emerging applications, such as mesoscale ocean eddies, ocean phytoplankton blooms, microplastics detection, target recognition, river flow, desert studies, natural hazards and landslides monitoring., This work was supported by the Henan International Science and Technology Cooperation Key Project (Grant No. 241111520700) and Strategic Priority Research Program Project of the Chinese Academy of Sciences (Grant No. XDA23040100)., Peer Reviewed, Postprint (published version)