(a) Map of ROTI at 1150 JST on July 4, 2019, which have been mapped onto an altitude of 100 km. The diamonds show the locations of the six Rx stations of NAV signals (purple = Sarobetsu, light blue = Oarai, green = Chofu, blue = Sugadaira, orange = Kure, and red = Onna). (b) Distribution of all the possible reflection points of EsAPs detected at the six Rx stations. The red cross marks represent the reflection points, which have been superimposed on ROTI map. (c) Same data as (b), but imaginary reflection points are filtered out.