Tropospheric Impairment Prediction at High Frequencies Training
Tropospheric Impairment Prediction at High Frequencies Training Course Description
This 4-day Tropospheric Impairment Prediction at High Frequencies Training is aimed at satellite communications engineers who wish to increase their understanding of the impact that the atmosphere, and particularly the troposphere, has on geostationary satellite links. The course will present the concepts going from general elements to specific techniques and illustrate them using practical examples of satellite coverage planning for DTH and broadband services, incorporating Matlab® and VBA-based implementations of the current ITU-R prediction models.
With onsite Training, courses can be scheduled on a date that is convenient for you, and because they can be scheduled at your location, you don’t incur travel costs and students won’t be away from home. Onsite classes can also be tailored to meet your needs. You might shorten a 5-day class into a 3-day class, or combine portions of several related courses into a single course, or have the instructor vary the emphasis of topics depending on your staff’s and site’s requirements.
Review of basic geostationary communication link elements. The basic link equation: Uplink and downlink performance; Satellite transfer and transponder modes of operation; G/T calculation and recommendation BO.790; Radiation pattern envelopes and recommendation S.580; Off-axis EIRP density limits and recommendation S.524.
Modeling propagation impairments by cumulative distributions. Cumulative distributions: what they are and how they are calculated. Rationale behind “percent of time” and “percentage of exceedance” figures, “any month” performance objectives: the concept of worst-month, yearly and monthly availability objectives for geostationary satellite communication links (Recommendations BO.1696, S.1806).
Calculation of the total link availability and the breaking margin concept.
Impact of the troposphere on high frequency satellite communication links: Tropospheric propagation impairment prediction. Revision of current ITU-R P. series recommendations for tropospheric impairment modeling: rainfall attenuation, cloud attenuation, atmospheric gases absorption, scintillation, and depolarization. Relative impact of each propagation impairment on a link, as a function of frequency (Ku, Ka, Q/V).
Evaluating the performance of current propagation models. Empirical modeling v. physical modeling. Case study on empirical modeling: The ITU-R P.837-5 Annex 1 model. Model prediction errors and limitation of current ITU-R recommendations. Next generation physical models for attenuation prediction and rain attenuation field modeling.
Example: Direct-to-home coverage planning exercise. A study of satellite coverage planning for a broadcasting service, incorporating the monthly availability targets given in BO.1696 and comparing results obtained using the current ITU methods and using physical models.
Mitigating the impact of tropospheric propagation impairments at high frequency. Signal diversity, site diversity, power control.
Example: IP Broadband satellite system incorporating multiple gateway diversity. Total gateway-to-user link (forward) availability considering site diversity (two and three sites).
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