The purpose of this advisory is to provide information about the Iridium Time (IRT) Epoch Halftime event. This notification is to assure OTT HydroMet customers who use Iridium Time in their applications that the logger will function properly before and after the upcoming halftime event on June 25, 2020 at 13:29.21 UTC. During prior Iridium Halftime transitions, Iridium has noted that some partners were using the IRT in a manner that might cause issues when signed instead of unsigned when 32-bit integer variables are used. Also note that this is a ‘mid-epoch’ or ‘Halftime’ rollover and not a true ‘full epoch’ rollover.
OTT HydroMet has validated that the current SUTRON Loggers including:
- SatLink 3
- XLink 100 / 500
All handle the ‘halftime transition’ properly as they all use the necessary unsigned 32-bit arithmetic. There is no action necessary for the customer that is using Iridium with OTT HydroMet loggers.
More info on the SUTRON Loggers: