Aeronautical Information Manual (AIM), page 88

Index   87 -- Page 88 -- 89

DGPS detects the position of GPS satellites relative
to GPS receiver equipment and broadcasts differen-
tial corrections over the VHF digital radio.

4. Category I Ground Based Augmentation

System (GBAS) will displace SCAT-I DGPS as the
public use service.

AIM, Paragraph 5-4-7 f, Instrument Approach Procedures

1-1-34 Navigation Aids

Page 88 of the Aeronautical Information Manual (AIM.pdf)
AIM: Official Guide to Basic Flight Information and ATC Procedures

Index   87 -- Page 88 -- 89