The satellite distance radiometer with a passive retroreflection of a request radio signal

In prospect projects of the lunar information and navigation support system, the using of a satellite range finder for solving the problem of ballistic support of near-moon spacecrafts is considered. In this paper we consider a mathematical model for calculating the radio line of a satellite rangefinder with passive retro reflection of the requested radio signal from selenodetic points. The model allows the calculation of the signal-to-noise ratio in the reflected radio signal and the standard deviation of the determination of the distance from the spacecraft to the passive radio retroreflector under various conditions. The calculations take into account both the reflection of the signal from the radio retroreflector and from the surrounding surface lunar soil. Various types of radio retroreflectors in the form of combinations of corner reflectors and in the form of a Luneburg lens are considered. The calculations of the radio line using the indicated types of retro radio reflectors for different values of the orbit height, signal frequency and other parameters are performed. It is shown that, at certain values of the parameters of the radio line, the standard deviation of the determination of the range of the order of units of meters and less is achieved both for the Luneburg lens and the combined angular reflector. The final choice should be made taking into account their mass, as well as the possibilities of transforming the radio retroreflector from transportation to working condition.