RINEX Version 2 is the format used by the IGS for operational data holdings. However, data support for additional GNSS, such as Galileo, QZS, and BeiDou, uses an enhanced version of RINEX available in Version 3. The CDDIS provides an archive of data from these additional GNSS through the IGS Multi-GNSS Experiment (MGEX).

The IGS established MGEX to track, collate and analyze all available GNSS signals, including Galileo, QZSS, and BeiDou, as well as modernized GPS and GLONASS satellites and any space-based augmentation system (SBAS) of interest. Analysis centers will attempt to estimate inter-system calibration biases, compare equipment performance and further develop processing software capable of handling multiple GNSS observation data.

The CDDIS is one of three IGS data centers supporting the IGS MGEX, expanding its data archive and distribution service to include data from participating multi-GNSS receivers, products derived from the analysis of these data, and any required metadata for the experiment. The archive now contains daily and hourly 30-second and sub-hourly 1-second data from an additional 100+ stations in RINEX V3 format. The CDDIS developed software to extract metadata from the RINEX headers for use in reporting and archive management. The software is also used to generate daily status files summarizing data holdings similar to those provided in the CDDIS IGS operational directories. However, data quality information, as produced by TEQC, is not available through this software.

The MGEX data are available within the campaign subdirectory structure in the CDDIS archive. These data are currently provided in RINEX V3 format.

The starting directory for these files is:

https://cddis.nasa.gov/archive/gnss/data/

Append the following directories and file names to the starting directory:

daily/YYYY/DDD/YYt/XXXXMRCCC_K_YYYYDDDHHMM_01D_30S_tt.FFF.gz  (daily 30-second files)

hourly/YYYY/DDD/HH/XXXXMRCCC_K_YYYYDDDHHMM_01H_30S_tt.FFF.gz  (hourly 30-second files)

highrate/YYYY/DDD/YYt/HH/XXXXMRCCC_K_YYYYDDDHHMM_15M_01S_tt.FFF.gz  (15-minute 1-second files)

as described in the table below.

Code	Meaning
XXXX	4-character IGS station name
M	monument or marker number (0-9)
R	receiver number (0-9)
CCC	ISO country code
K	Data source: R = From Receiver data using vendor or other software S = From data Stream (RTCM or other) U = Unknown
YYYY	4-digit Gregorian year
DDD	3-digit day of year
YY	2-digit year
t	type of data: d = Hatanaka-compressed observation data f = Beidou navigation message data g = GLONASS navigation message data h = SBAS payload navigation message data l = GALILEO navigation message data m = meteorological data n = GPS navigation message data o = observation data p = mixed GNSS navigation message data q = QZSS navigation message data s = observation summary files (extracted from RINEX header)
HH	2-digit hour
MM	2-digit minute
tt	type of data: GO = GPS Obs. RO = GLONASS Obs. EO = Galileo Obs. JO = QZSS Obs. CO = BDS Obs. IO = IRNSS Obs. SO = SBAS Obs. MO = Mixed Obs. GN = Nav. GPS RN = GLONASS Nav. EN = Galileo Nav. JN = QZSS Nav. CN = BDS Nav. IN = IRNSS Nav. SN = SBAS Nav. MN = Nav. (All GNSS Constellations) MM = Meteorological Observation
FFF	File format: rnx = RINEX crx = Hatanaka Compressed RINEX
.gz	Compressed file