Unique Considerations for a SDARS Signal Availability Model Using A Highly Inclined Elliptical Geosynchronous Satellite Constellation
- Paper number
IAC-06-B3.3.07
- Author
Mr. Patrick T. Anglin, Sirius Satellite Radio, United States
- Year
2006
- Abstract
The discussed North American SDARS (Satellite Digital Audio Radio System) —utilizes 3 satellites each in a highly inclined elliptical geosynchronous orbit separated by 120 degrees in RAAN (Right Ascension of the Ascending Node)— requires several modifications to a traditional signal availability, the percentage of the time that a mobile user has reception, calculation model. The unique constellation causes two of the primary inputs –link margin and elevation angle from the receiver to the satellite—for determining the satellite signal availability to vary throughout the day for a mobile user in a certain location. There are also certain delivery system enhancements that improve the system’s satellite signal availability, including signal diversity, space diversity, time diversity and forward error correction that affect the signal availability calculation. Consequently, this SDARS delivery system requires a more refined model than the standard the EERS (Extended Empirical Roadside Shadowing) model, which uses the elevation angle, link margin and frequency of a digital satellite signal to determine the satellite signal availability of a mobile receiver under foliage. A modified version of the EERS model that accounts for this system’s distinctive orbit, receiver and system design has been developed to accurately predict the expected availability values throughout the service area. The calculations involved in accurately modeling the previously mentioned receiver and signal enhancements of the delivery system and the algorithms enabling the determination of the satellite signal availability over the entire service area at any moment in time included in this modified EERS model are discussed in this paper.
- Abstract document
- Manuscript document
IAC-06-B3.3.07.pdf (🔒 authorized access only).
To get the manuscript, please contact IAF Secretariat.