1. Iridium project, https://www.iridium.com (1996, accessed 30 May 2021).
2. Globalstar project, https://www.globalstar.com/en-us/corporate/home (2000, accessed on 30 May 2021).
3. OneWeb system, https://www.oneweb.world (2018, accessed 30 May 2021).
4. Starlink program, https://www.starlink.com/ (2019, accessed 30 May 2021).
5. Hongyun project, http://www.casic.com.cn (2018, accessed 30 May 2021).