The UBX-RXM-SFRBX message (Broadcast Nav Data Subframe) does not containing any timing information. But when decoding and applying SBAS data, I need to know the time-of-validity of the message. The SBAS msg tov is defined as the start of the epoch when the first bit was transmitted from the GEO. So, normally, this is one second prior to when the SBAS data message was received. Is there a way to determine when the SBAS subframe was received? Section 9 of the Protocol & Spec (Broadcast Navigation Data) simply states "a separate message is generated every time the receiver decodes a complete subframe of data from a tracked signal." I need the time when that message was generated.