PRN     Azimuth(d)     Elevation(d)   Vertical-TEC(tecu)    Slant-TEC(tecu)       S4(L1/L2)    2017/12/20-12:27:50
G02     61.2           30.5                3.6 +/-    1.70       6.3 +/-    1.70  0.030 / 0.020
G05     57.7           60.9                3.0 +/-    0.44       3.4 +/-    0.44  0.030 / 0.020
G12     186.3          33.3                5.4 +/-    1.30       8.8 +/-    1.30  0.040 / 0.040
G13     129.0          15.5                4.6 +/-    2.82      11.3 +/-    2.82  0.040 / 0.040
G15     162.3          13.1                5.4 +/-    4.16      14.0 +/-    4.16  0.070 / 0.070
G20     209.7          57.7                6.2 +/-    0.59       7.2 +/-    0.59  0.110 / 0.080
G21     273.5          22.0                3.0 +/-    1.99       6.4 +/-    1.99  0.270 / 0.360
G25     235.9          51.4                5.8 +/-    2.23       7.2 +/-    2.23  0.240 / 0.360
G29     332.2          58.8                2.1 +/-    0.49       2.4 +/-    0.49  0.060 / 0.090