There is a tremendous amount of data that must be encoded in the gps signal. If everything were packed as 8, 16, or 32 bit words there would be a tremendous amount of wasted bandwidth. If you look up IS-GPS-200 you can learn all about the numerous messages and how they are packed. The 10 byte GPS week and it’s rollover is not a limitation for the GPS system itself. It just forces GPS receiver venders to come up with ways to recognize the rollover and not reset your time back 19 and a half years. Some of the newer signals coming on line do add a few extra bits to avoid this rollover, but at some point, everything rolls over.
Sometimes it’s better when rollovers are more frequent. That way there are folks around who understand the design and how to get through it. Imagine if you had a system that you relied upon as much as we rely on GPS but it only rolled over every century. You’d be hard pressed to find anyone who still had the skill set to be aware of the issue, much less know how to operate through it. All the designers would be long gone.
Magnum, I totally understand all your points as I have written a fair number of assembly language interfaces wherein flags are buried in bytes, etc. Please notice that I did not say everything had to be on a full byte boundary, just something as dynamic as a time-keeping component should have it’s own little chunk. Besides 6 bits is not going to bring down the kingdom. Look at it this way: in the code the 10 bits that make up the timer have to extracted from the byte (word, whatever) and placed in a work area. Then the timer is incremented. The 10 bits are then masked back into the storage byte (word, ...). That takes 6 or more (minimum) machine level instructions. If the timer had it’s own byte (word, yadda-yadda), 3 instructions tops. So cramming a few flags into a word with the timer is slower as well as more complicated.
I know it seems that I’m picking nits a bit but I really do understand these things. IMHO this was a poor design decision.
Anyway, stay cool ... and Spring Forward tonight!