For a complete description of the ROB-IONO product, please refer to: 
 
Bergeot N., Chevalier J.-M., Bruyninx C., Pottiaux E., Aerts W., Baire Q., Legrand J., P. Defraigne and W. Huang 
Near real-time ionospheric monitoring over Europe at the Royal Observatory of Belgium using GNSS data
J. Space Weather Space Clim., 2014.

The compressed ROBRdddHmm.yyI.Z IONEX files are named such as:

ROBR 	: Royal Observatory of Belgium near Real-time product
ddd 	: Day of Year 
H	: Hour in UTC of the first GPS observations used (A = 0, B=1, C=2 ....)
mm 	: Minute in UTC of the first GPS observations used (00, 15,30, 45)
yy	: Year
I	: Ionospheric product

Contact address: iono@gnss.be
Contact persons: nicolas.bergeot@oma.be and jean-marie.chevalier@oma.be 
Web site : www.gnss.be