Fig. 11From: The ionospheric condition and GPS positioning performance during the 2013 tropical cyclone Usagi event in the Hong Kong regionSpatial distribution of cycle slips on GPS L1 (a) and L2 (b) signals derived from the HKPC station on 24 September 2013. The blue lines denote the trajectory of the GPS satellites projected on the plane at the altitude of 350 km. The red triangles on the blue line represent cycle slipsBack to article page