(a–d) A sequence of images from the ASIP at channel 630.0 nm showing the observation of two polar cap patches (patches C and F). The black circles and plus signs indicate the locations of GPS satellites. The size of the circles relates to the σ_ϕ strength showing on the right of the all-sky images, whereas black plus signs mean no scintillation was observed (σ_ϕ < 0.1). (a, b) Patch C came into the FOV and continued to move southward. The scintillation was observed when the patch passed through the line of sight (LOS) of several satellites. (c, d) Patch F entered into the LOS of PRN12 and PRN24, and enhanced phase scintillations were observed. (e) The temporal variation of optical emission at 630.0 nm channel corresponding to the locations of PRN11 in units of log (counts). (f) σ_ϕ (black) and the Slant TEC (red line) from PRN11. σ_ϕ are plotted as black circles when σ_ϕ > = 0.1, otherwise as plus signs. The shaded regions in (e, f) correspond to the time period when patch C passed through the LOS of PRN11. The data gap from 20:50 UT to 21:05 UT in (e, f) is due to loss of lock; PRN11 moved out of the FOV at 22:35 UT, therefore there is no data after this time. (g, h) The same format as (e, f) but for PRN24. The shaded regions show the pass of patch F.