I use a Uno and a u-blox NEO-6M GPS module for a GPS controlled clock.
I would like to have a character on the display indicating if the watch is locked to the satellites or not. (The LED on the GPS module will not be visible when the project is finished.)
I tried to use gps.time.isValid() to get that indication. However, with some metal around the module it keeps sending the time even the LED flashing stops. OK, it can make a pretty good forecast regarding time
Then I tried to use gps.location.isValid() as the module cannot forecast its location (I hope).
That works. The indicator change according to the LED flashes.
My question now is: Is there a better (i.e. more professional) method in TinyGPS+ to use for this?
If your using the GPS as the source for a clock, then you really need to be also checking if the time being published is actually up-to date UTC.
The time published can be a few seconds out after the initial power up of the GPS and it can take 12 minutes, possibly more, for the appropriate update from the GPS system.
You can check whether the UTC is updated manually, not aware of a library that has these functions.
But then the GPS published time being out by a few seconds might not be a concern.
The time published can be a few seconds out after the initial power
up of the GPS and it can take 12 minutes, possibly more, for the
appropriate update from the GPS system
Is that right? That the system reports a time that has not been updated? How can it be?
How would you check it manually? GPS was supposed to be my reference.
So you mean that after 12 minutes or so, everything is fine?
He is right. The gps time get corrected with leap seconds in intervalls 12.5minutes. So the time you get, is corrected in the gps reciver with leap secounds, only, from date of the firmware you are using. Gps time and utc time is not the same. Currently, we have 18 leap seconds.
If you watch a GPSs output carefully, from power up, you will see some minutes down the line the GPS reported time suddenly change.
Not so much an issue for a clock, but if you were using the GPS reported time in some synchronisation system there could be issues if the referance were to suddenly change by 2 or 3 seconds.
I do believe there are plans to abolish the regular changes to leap seconds due to the problems it causes.........
There are commands you can send to a GPS to read its current value of leap seconds and whether its been updated to the correct value or not.
Yes. But I thought the GPS system was broadcasting UTC.
I just have to understand you completely right:
Is it so, that when the clock has been running for > 12.5 minutes, I get correct UTC?
In some telescope control contexts, I use a Navilock GPS device, which goes into my computer via USB. There NMEATime Panel corrects the computer's clock. Do you think it is corrected to GPS time or UTC? I need UTC accurate to 0.01 second.
