Implausible Time Records

So...Â* Does having a 3D fix with, say 8 satellites, constitute good GPS
time?Â* I would think so.

On 5/20/2019 3:27 PM, kinsell wrote:
On 5/20/19 2:42 PM, wrote:
I’ve not heard back from Lxnav yet, but I had a private email from a
very smart person that pointed out that both the October 2 and
October 4 flights had the clock jump after takeoff but before soaring
began.Â* The flight this week had the clock jump a minute or so after
soaring began, and thus is likely why OLC flagged this one and not
the other two.Â* It appears that the clock jump is 7 to 8 minutes
after the unit is turned on.Â* Since I generally do not turn the
system on until just before takeoff, it is believed that the system
is using an internal clock until it syncs with the gps satellites and
then resets the clock which may be different by a couple of seconds.
My plan is to turn the 9070 on a few minutes before launch to allow
it to sync clocks to see if that helps.Â* It is not clear to me if
Dan’s issue is similar to mine or different.

MS


They do have clocks to help achieve lock on the satellites, but I've
seen the reported time jump immediately after lock was achieved.Â*
Don't know why the 9070 would wait minutes after achieving lock before
correcting the time.Â* Maybe an issue of 2D vs 3D lock.Â* If you're
turning on the logger immediately before takeoff, you're risking
losing the early part of the flight entirely, not just having time
problems.

Dan was having lots of gps altitude dropouts during flights, that
might just be jamming.Â* He did have a time jump just at liftoff, so
that fits in with switching the clocks.

--
Dan, 5J