US Government security requirements no longer permit CDDIS to offer data via traditional unencrypted anonymous ftp; this service was discontinued on October 31, 2020. All data are still available, however access must be via HTTPS or ftp-ssl.
Instructions with examples and our FAQ can be found at: https://cddis.nasa.gov/Data_and_Derived_Products/CDDIS_Archive_Access.html.
If you still have difficulty after reading and attempting the examples on that page, please contact us at support-cddis@earthdata.nasa.gov.

The CDDIS began archiving data from flight receivers on board LEO satellites in support of the IGS LEO Working Group. Satellite data available in this archive include CHAMP, ICESat-1, Jason-1, and SAC-C. All flight receiver data are stored in RINEX format.
The starting directory for these files is:
Append the following directory and file names to the starting directory:
SATNAME/YYYY/DDD/SSSSDDD0.YYt.Z
Satellite Name |
---|
champ |
icesat |
jason |
sac-c |
Satellite Name | Code |
---|---|
champ | cham |
icesat | ice1 |
jason | jaso |
sac-c | sacc |
as described in the table below.
Code | Meaning |
---|---|
SATNAME | satellite name |
YYYY | 4-digit year |
DDD | 3-digit day of year |
SSSS | satellite code |
YY | 2-digit year |
t | type of data: d = Hatanaka-compressed observation data s = observation summary files (output of TEQC) o = ICESat GPS data in standard RINEX format pc = ICESat position solution from receiver |
.Z | UNIX compressed file |
