The radar equation for remote radio sounding of distributed targets with ultra-wideband radio signals

Ultra-wideband (UWB) radio signals are signals the bandwidth of which is of the order of magnitude of or equal to the average value of the frequency. Such signals have been widely employed for sounding natural resources as well as in air navigation radar. We have studied the possibility of using UWB signals for remote radio wave sounding of the atmosphere, the ionosphere, the magnetosphere, and the near-Earth environment. For this purpose in particular, the radar equation is derived for remote sensing instruments employing radio wave techniques; it takes into account the features of distributed targets and relates the signal-to-noise ratio at the input of the receiving system to the parameters of the facility and the medium. The mathematical models of UWB signals are suggested. The computer simulations of the dependence of the signal-to-noise ratio q on the wideband index and on the mean frequency of UWB signals, as well as on the parameters of the facility and media, are performed. The applicability of these results to the radio sounding of near-Earth space with the mesosphere-stratosphere-troposphere (MST) radar, incoherent scatter radar and partial reflection facilities is discussed