Lawal, L. S., and C. R. Chatwin. “A REVIEW OF GLOBAL NAVIGATION SATELLITE AND AUGMENTATION SYSTEMS”. IJRDO - Journal of Electrical And Electronics Engineering (ISSN: 2456-6055), Vol. 5, no. 3, Mar. 2019, pp. 01-21, https://ijrdo.org/index.php/eee/article/view/2731.