USCG, High HDOP Advisory
The U.S. Coast Guard Navigation Center issued a High Horizontal Dilution of Precision (HDOP) Advisory stating that GPS users in certain parts of the world may experience a short period of high HDOP/PDOP on October 8 as a result of a routine Delta-V maneuver with satellite #52 (PRN-31). (10/6/09).
(Source: Bryant’s Maritime News)