The ionosphere is the ionized part of Earth’s upper atmosphere, which is usually characterized by irregularities and fluctuations in plasma density. The ionospheric irregularities can influence the propagation of trans-ionospheric radio waves and are thus of importance for any operations that rely on precise positioning with Global Navigation Satellite Systems (GNSS). Therefore, understanding the ionospheric plasma irregularities is of both scientific and practical interest. In this report, we will summarize the plasma irregularities related studies by using measurements from low Earth orbiting (LEO) satellites, like CHAMP, GRACE, GOCE, and Swarm. In addition, the influence of plasma irregularities on the GNSS signal, especially for the receivers onboard LEO satellites have been also discussed.