beautypg.com

Grundig Digital Radio User Manual

Page 74

background image

DIGITAL RADIO GUIDE

SATELLITE TRANSMISSION - SIRIUS / XM

74

Changes Made For Sirius Inclined Elliptical Orbits

Parameter

Geostationary

Inclined Elliptical

Dry Mass

1300 kg

1575 kg

RF power (operating)

2.5 kW

4 kW

DC power – EOL
Solar Array
Battery

7.5 kW
7.5 kW

8.5 kW
8.8 kW

Control System

3-wheel mom bias

4-wheel mom bias
On-board orbit
propagator

Control Modes

Orbit Normal

Orbit Normal
Yaw Steering

TX Antenna

Fixed Gregorian
Gain 27.8 dBi;
Cross-pol 24 dB

Gregorian; two axis
steering 360º rotating
shaped subreflector
Gain 27.2 dBi; Cross-
pol 28 dB

RX Antenna

Fixed offset fed

Offset fed; two axis
steering

Solar array

2x4 panel HES

2x5 panel HES

Battery

2x32 cell - 149 AH

2x34 cell - 178 AH

TT&C

X, C and S bands
CONUS ground station
Limited motion antennas

C and S bands
2 near equatorial
ground stations Full
motion antennas

Launch Vehicle

Ariane

Proton

The launch of the Sirius Satellite Radio constellation marks the first use of satellites for
Digital Audio Radio Service broadcasting in the United States. The three high power
direct broadcast satellites will provide service for millions of subscribers. The Sirius Radio
system is the world’s first satellite broadcast system using non-geostationary orbits.

The use of inclined elliptical orbits coupled with multiple modes of transmission diversity
provides notable advantages for broadcast service to the mobile market. Pioneering
technology was developed and implemented by Sirius Satellite Radio and Space
Systems/Loral in order to accomplish this unique achievement.

5.2.2

Deployment Status

Current population and transmission status of Sirius and XM satellite radio services is
shown in the following chart.

Continental US

Coverage

Satellites

Ground

Repeaters

Sirius Satellite Radio

100%

3 in HEO

~100

XM Satellite Radio

100%

2 in GSO

~800