Modeling and inverting radio occultation signals in the moist troposphere

Refractivity is assumed spherically symmetric, and vertical profiles are reproduced from high-resolution tropical radiosondes. As a result, the characteristics of the signals, which are important for their tracking in low Earth orbit, are evaluated: the spectral bandwidth, ~50 Hz, and the random phase acceleration, ~1000 Hz/s.

The complex signals are inverted with the use of two radio holographic methods: back propagation and sliding spectral (radio optics). For the back propagation method, finding the position of the auxiliary trajectory which provides an unambiguous bending angle function of impact parameter appears to be a problem. For the sliding spectral method a simple technique, which takes into account the whole spectral content of the signal without identification and selection of local spectral maxima, is introduced and tested.