Performance of the DBS Satellite Receiver under the Impact of Rainfall and Terrestrial Interference

This article presents a new study on the feasibility of operating a direct broadcasting satellite (DBS) system under the effect of both precipitation and interference from a fixed service (FS) at K-band in a semiarid region. The carrier-to-noise plus interference ratio (CNIR) as a protection criterion has been adopted to make sure that the receiver of the DBS system operates with an acceptable performance under rainfall and interference from FS. Various measured data for rainfall in different areas have been utilized to investigate different rain rate exceedance percentages. Results have been shown that areas with high rain rates have a small CNIR at the DBS receiver and require large protection distances compared to low-rain rate areas and vice versa. Some mitigation techniques have been suggested to alleviate the effect of rain and terrestrial interference on the DBS receiver performance.

Investigation of the influence of surfaces between basic stations and satisfactory recognition on the accuracy of coordinating definitions

The distance between different base stations and the mobile receiver, as well as errors of coordinate definitions at different distances between the base station and the mobile receiver are investigated. For realization of the set tasks the following methods of research were applied: field measurements, mathematical modeling method and methods of mathematical statistics for the processing of experimental data. The degree of influence of distances between the base station and the satellite receiver on accuracy of coordinate definitions in RTK-mode is established.

Methodology to estimate ionospheric scintillation risk maps and their contribution to position dilution of precision on the ground

Satellite-based communications, navigation systems and many scientific instruments rely on observations of trans-ionospheric signals. The quality of these signals can be deteriorated by ionospheric scintillation which can have detrimental effects on the mentioned applications. Therefore, monitoring of ionospheric scintillation and quantifying its effect on the ground are of significant interest. In this work, we develop a methodology which estimates the scintillation-induced ionospheric uncertainties in the sky and translates their impact to the end users on the ground. First, by using the risk concept from decision theory and by exploiting the intensity and duration of scintillation events (as measured by the $$S_4$$ S 4 index), we estimate ionospheric risk maps that could readily give an initial impression on the effects of scintillation on the satellite-receiver communication. However, to better understand the influence of scintillation on the positioning accuracy on the ground, we formulate a new weighted dilution of precision (WPDOP) measure that incorporates the ionospheric scintillation risks as weighting factors for the given satellite-receiver constellations. These weights depend implicitly on scintillation intensity and duration thresholds which can be specified by the end user based on the sensitivity of the application, for example. We demonstrate our methodology by using scintillation data from South America and produce ionospheric risk maps which illustrate broad scintillation activity, especially at the equatorial anomaly. Moreover, we construct ground maps of WPDOP over a grid of hypothetical receivers which reveal that ionospheric scintillation can also affect such regions of the continent that are not exactly under the observed ionospheric scintillation structures. Particularly, this is evident in cases when only the global positioning system is available.