The influence of geomagnetic activity on slips of navigation signals of the global positioning system (GPS), as well as an increase in the amplitude of jumps in the total electron content at high latitudes, has been studied in detail. It is shown that the navigation signal of the L2 frequency is subject to more frequent malfunctions than the L1 frequencies, both in calm conditions and during geomagnetic disturbances. The probability of total electron content jumps is higher than the probability of phase slips at the L1 and L2 frequencies. The maximum disruptions and the frequency of large jumps in the total electron content are observed during the recovery phase of the geomagnetic substorm. The data from the whole-sky camera, magnetometers, and the interplanetary magnetic field used in this study make it possible to monitor the time evolution of a substorm and to study it in detail. The indicated features of the signal behavior are apparently caused by the precipitation of auroral particles, which usually occur during geomagnetic substorms in high latitude regions.