Use of ultra-small space vehicles for studying near-Earth plasma by radiophysical methods

The paper shows the possibility to measure plasma density and its fluctuations in the ionosphere on ultra-small space spacecraft using radiophysical methods that allow determining the characteristics of the medium through which radiation is transmitted. It is assumed that each spacecraft will have a navigational satellite receiver, as well as a device for emitting and detecting a signal at two multiple frequencies in the radio band. With this approach, information on plasma density is contained in the received phase difference. Radio receivers and radio transmitters on satellites constantly exchange radio signals and then it is possible to determine the electron concentration and its fluctuations from the phase shift. The authors obtained numerical estimates of the resulting phase difference for different frequencies from 10 MHz to 10 GHz with typical ionospheric parameters depending on the distance between the satellites. Calculations were also made to determine the maximum distance between satellites at which it is possible to receive a signal, provided that the transmitter power is 2 watts.