Ковалевський, Е.О., В.В. Конін, and О.С. Погурельський. “Using Satellite Signals of Different Frequencies to Improve the Accuracy of Navigation Definitions”. Proceedings of National Aviation University 34, no. 1 (January 1, 2008): 8–11. Accessed May 3, 2024. https://jrnl.nau.edu.ua/index.php/visnik/article/view/1522.