Differential GPS - Understanding GPS: Principles and Applications - page 434

Anchorage

Cold Bay

Juneau

Seattle Brewster

Billings

Boston

Minneapolis

Clarksburg

Oakland Cleveland

New York

Chicago

Salt Lake
City

Washington D.C.

Kansas City

Denver

Santa Paula

Memphis
Atlanta

Palmdale

Albuquerque

Fort Worth
Houston

Jacksonville

Miami

Honolulu

San Juan

Legend
Wide-area reference station
Wide-area master station
Ground uplink subsystem

WAAS architecture:
25 WRS
2 Master stations

2 Geosynchronous satellites

3 GUS

Figure 8.26 WAAS ground network.

70

MON
(Canada)

60

RIMS
MCC
NLES
PACF
ASQF

50

40

30

BNG
(India)

20
− 40

10 0 10 20 40 −

30

− 30

− 20

KOU
(French Guiana)

HBK (South Africa)

MAUR

Figure 8.27 EGNOS ground network.

data from the entire network are processed to develop estimates of each GPS satel-
lite's true position and clock error, corrections based on the differences between the
network's estimates of these parameters and the values in the broadcast GPS naviga-
tion data, and an estimate of the vertical ionospheric delay error across the service
area. Each central processing facility also checks for “problem” satellites (e.g., those