That is a very cool blog, really nicely documented. What was the brand of PLB involved in that situation. For sure a PLB with an internal GPS is essential. I've never seen a higher end PLB or EPIRB (mcmurdo fastfind) take longer than few minutes to download the ephemeris/almanac data but that's not saying it couldn't take longer. I recall, in my marine radio training, the US coast guard evaluations backed that up. I'm trying to find some documentation on that.
In EPIRB/PLB testing i've been involved with (marine mostly) the truncation errors never amounted to more than 20m of resolution, but in that particular situation in your blog perhaps there was extensive obfuscation of the GPS satellites? Did they actually turn off the PLB?
At any rate, it makes total sense to always carry some small pen flares (we do).
Again, very cool blog!
Can't remember the model of PLB, possibly McMurdo
They were in very heavy rain, in a mostly east - west valley so GPS signal was probably as bad as it was going to get. This also affects the speed at which the ephemeris will download, as well as the time to get a fix. The other consideratons are where they placed the PLB, of that I am not sure.
I've been using the wrong word to describe the cold start, time to first fix process by describing it as "downloading the ephemeris". When a GPS has been off for a long time it needs to download the almanac which is transmitted every 12.5 minutes, and can takes 12.5 minutes to download. I'm guessing the worst case to download this is about 15 minutes if you miss the beginning of a transmission and your algorithm can't mash two almanacs together.
If the signal is weak or there is an error in the download it could take longer of course.
You're right about the truncation, it would amount to approximately 20m - in this case that would still have given us uncertainty as to which bank of a confluence of three creeks they were on!