FAST ALGORITHM OF MULTI-GNSS DATA PROCESSING FOR SENSING THE IONOSPHERE

• Main Author: Kurnia Utama, Aditya
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/73258
• Institution: Institut Teknologi Bandung

<p align="justify">The development of fast and effective algorithms for calculating Vertical Total Electron Content (VTEC) and Differential Code Biases (DCB) parameters with multi-Global Navigation Satellite System (multi-GNSS) has been created. This fast algorithm can perform parameter calculations on local (Local Ionospheric Models, LIMs) and global (Global Ionospheric Models, GIMs) coverage areas. Utilization of the orthogonal transformation with the QR decomposition method in this fast algorithm can restructure the Simultaneous Least Squares Adjustment (Sim-LSA) matrix which has large dimensions to become smaller and has special features in its matrix structure. This feature allows the fast LIMs algorithm (ITB-LIMs) to perform separate estimations between high-resolution VTEC parameters carried out sequentially and DCB which are carried out recursively in each batch. The ITB-GIMs method has an advantage in its capability in processing high-order VTEC and DCB which are carried out simultaneously. Transformation orthogonal transformation allows the GIMs algorithm to restructure the matrix of each sub-batch so that it has small dimensions, so that the stacking of sub-batch matrices will be smaller, and the calculation process will be more efficient. The orthogonal transformation process makes the ITB-LIMs algorithm have a computational speed of 2.5 times faster and the capacity of the number of stations that can be processed is greater than the standard method with Sim-LSA which runs on computer with specification Intel® Core™ i7-8550U CPU @ 1.80GHz x 8 RAM 20 GB. Meanwhile, the ITB-GIMs algorithm can run on standard specification hardware with a much larger capacity of the number of stations that can be processed compared to the standard method which is only capable of running 7 stations. From the tests that have been carried out, it was found that the use of orthogonal transformations has results like the standard method which can be solved with a more efficient computational load. The implementation of the ITB-GIMs and ITB-LIMs algorithms on the local Indonesian and global IGS networks provides VTEC and DCB results that match those of the IAACs, with ITB-LIMs having the advantage of high temporal resolution so that they can capture local ionospheric phenomena in the Indonesian region.