Improvement of Reflection Detection Success Rate of GNSS RO Measurements Using Artificial Neural Network

• Published in: IEEE transactions on geoscience and remote sensing Vol. 56; no. 2; pp. 760 - 769
• Main Authors: Hu, Andong, Wu, Suqin, Wang, Xiaoming, Wang, Yan, Norman, Robert, He, Changyong, Cai, Han, Zhang, Kefei
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.02.2018; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Artificial intelligence; Artificial neural networks; Climate; Computational efficiency; Computer applications; Computing time; Cost function; Data processing; Detection; Earth; Earth surface; Global navigation satellite system; Holography; Ionosphere; Learning algorithms; Learning theory; Machine learning; Meteorology; Methods; Navigation; Navigation satellites; Neural networks; Performance assessment; Performance testing; Radio; Radio occultation; Reflection; reflectivity; Regularization; remote sensing; Satellite broadcasting; Satellites; Training data; Weather forecasting
• ISSN: 0196-2892; 1558-0644
• DOI: 10.1109/TGRS.2017.2754512

Global Navigation Satellite System (GNSS) radio occultation (RO) has been widely used in the prediction of weather, climate, and space weather, particularly in the area of tropospheric analyses. However, one of the issues with GNSS RO measurements is that they are interfered with by the signals reflected from the earth's surface. Many RO events are subject to such interfered GNSS measurements, which are considerably difficult to extract from the GNSS RO measurements. To precisely identify interfered RO events, an improved machine learning approach-a gradient descent artificial neural network (ANN)-aided radio-holography method-is proposed in this paper. Since this method is more complex than most other machine learning methods, for improving its efficiency through the reduction in computational time for near-real-time applications, a scale factor and a regularization factor are also adjusted in the ANN approach. This approach was validated using Constellation Observing System for Meteorology, Ionosphere, and Climate/FC-3 atmPhs (level 1b) data during the period of day of year 172-202, 2015, and its detection results were compared with the flag data set provided by Radio Occultation Meteorology Satellite Application Facilities for the performance assessment and validation of the new approach. The results were also compared with those of the support vector machine method for improvement assessment. The comparison results showed that the proposed method can considerably improve both the success rate of GNSS RO reflection detection and the computational efficiency.