The NASA Propagation Effects Handbook for Satellite Systems Design provides a systematic compilation of the major propagation effects experienced on space-Earth paths in the 10 to 100 GHz frequency band region It provides both a detailed description of the propagation phenomenon and a summary of the impact of the effect on the communications system design and performance Chapter 2 through 5 describe the propagation effects, prediction models, and available experimental data bases In Chapter 6, design techniques and prediction methods available for evaluating propagation effects on space-Earth communication systems are presented Chapter 7 addresses the system design process and how the effects of propagation on system design and performance should be considered and how that can be mitigated Examples of operational and planned Ku, Ka, and EHF satellite communications systems are given

Propagation effects handbook for satellite systems design. A summary of propagation impairments on 10 to 100 GHz satellite links with techniques for system design

An empirical model has been generated to estimate diversity gain on earth-space propagation paths as a function of earth terminal separation distance, link frequency, elevation angle, and angle between the baseline and the path azimuth. This analysis utilized 34 diversity experiments which have been conducted in Canada, England, Japan, and the United States during the past decade. The resulting model reproduces the entire experimental data set with an rms error of 0.73 dB. The separation distance dominates the dependence of the diversity gain. The dependence on link frequency is small but significant. No identifiable dependence on baseline orientation was found.

An improved model for diversity gain on earth-space propagation paths

Space diversity (the simultaneous use through a common operations centre of two, or more, satellite receivers on the ground to overcome severe path attenuation that might occur on one of the links) is a well known concept and many measurements have been made to assess its potential advantages. The experimental results to date, however, show a large variability in space-diversity performance. The paper reviews all the results known to the author, discusses the influence of various kinds of rainfall and analyses the principal causes giving rise to the variations in space-diversity performance. Microclimate, receiver base-line orientation, site separation and topography are concluded to be the prime causes of the variations in measured space-diversity performance, and broad guidance for selecting the sites for a space-diversity complex is given.

Nature of space diversity in microwave communications via geostationary satellites: a review

This paper contains the results of a radar study of path diversity performance on simulated earth-space communication links in the presence of rainfall. The McGiIl University 3 GHz radar was used to obtain three-dimensional fields of radar reflectivity. The radar reflectivities measured at resolution cells along the propagation paths of interest were converted to specific attenuation and these values of specific attenuation were then summed to yield the total path attenuation. This procedure was repeated along parallel earth-space paths to yield the path diversity performance. The results for the Montreal area indicate that path diversity performance is mildly dependent upon the orientation of the propagation path and weakly dependent upon the baseline orientation of the ground diversity terminals.

Path diversity for earth‐space communication links

[1] Intersite separation (ISS) between two terminals is one of the important parameters required for implementation of site diversity (SD), as a fade mitigation technique (FMT), in moderate to heavy rain conditions usually encountered in tropical climates This paper presents the findings of an experiment during the monsoon periods of years 2007 and 2008 It establishes the existence of micro rain cell (MRC) at a tropical site, Ahmedabad (2306°, 7262°), India, using measurements from tipping bucket rain gauge network Spatial extent of MRCs and derived attenuation cells is examined on the basis of their maximum occurrence for initial to mid and last spells of years 2007 and 2008 The analysis also presents ISS statistics of monsoon periods for both the years Microscale SD as FMT has been discussed on the basis of the calculated diversity gain at Ka band frequency in view of the proposed GSAT-4 satellite These are the very first findings of their kind over the region of study

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2008RS004093

Micro rain cell measurements in tropical India for site diversity fade mitigation estimation

The results of data obtained at The University of Texas at Austin in conjunction with the ATS-6 millimeter wave experiment are presented Attenuation measurements at 30 GHz and sky noise data at 20 GHz were obtained simultaneously at each of two sites separated by 11 km Space diversity reduces outage time for a system in Austin, Texas with a 10 dB fade margin at 30 GHz from 15 hours to 16 minutes per year The maximum cloud height shows a good correlation to the maximum attenuations measured

/pdf/ats-6-attenuation-diversity-measurements-at-20-and-30-ghz-1fmvr1tq2w.pdf

ATS-6 attenuation diversity measurements at 20 and 30 GHz

The results of data obtained at The University of Texas at Austin in conjunction with the ATS-6 millimeter wave experiment are presented. Attenuation measurements at 30 GHz and sky noise data at 20 GHz were obtained for 93 days simultaneously at each of two sites separated by 11 km and for 314 days at one site. The ratio of the loss at 30 GHz to that at 20 GHz due to rain varied from about 2 to about 4 with a median value of 2.65. This value was used to estimate 30 GHz losses for the 38.6% of time during attenuation events for which the satellite link was not available. Space diversity reduced outage time for a system in Austin, Texas, with a 10 db fade margin at 30 GHz from 3.8 hours to 4.1 minutes for the 93 days. Extrapolated to a yearly base this corresponds to 15 hours and to 16 minutes respectively. A plot of maximum observed cloud height against maximum hourly attenuation indicates that for a given attenuation level a lower limit is set for the maximum cloud height.

N. K. Wagner

Papers

ATS-6 attenuation diversity measurements at 20 and 30 GHz

Attenuation diversity measurements at 20 and 30 GHz