1. AGI, Systems Tool Kit (STK), from https://www.agi.com/products/engineering-tools.
2. Aiken, C.L.V., 1996. GPS Absolute Positioning Determination Concepts, Errors, and Accuracies, GPS classroom, chapter 5, viewed 22 March 2018, from https://www.utdallas.edu/~aiken/GPSCLASS/ch5.pdf.
3. Mathematical Model of Antenna Look Angle of Geostationary Communications Satellite Using Two Models of Control Stations;Ayansola;Int. J. Adv. Comput. Sci.,2012
4. The usefulness of GLONASS for positioning in the presence of GPS in Indian subcontinent;Banerjee;Navigat. J. Instt. Navigat.,2002
5. A study on GPS PDOP and its impact on position error;Banerjee;Indian J. Radio Space Phys.,1997