Differences in measurements with separate use of frequencies L1 and L2 for the application of satellite navigation in near-earth space

Traditionally the second frequency of the dual-frequency receiver is used to increase the accuracy of positioning by mitigating the influence of the ionosphere and other atmospheric effects on the signal. The presence of the useful signal at both frequencies is usually taken for granted, and it is indeed true for the Earth service zone, as the satellite antennas were primarily designed to ensure stable and reliable navigation in this zone. There is a certain difference in the radiation pattern between L1 and L2 frequencies. This plays an important role for satellite navigation in near-Earth space. The article provides the information about the use of the frequencies in the task of space navigation.