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Do not use date/time until we have a fix. #6

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denravonska
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It turned out that some (?) receivers use an old timestamp in at least GGA when they
do not have a position. This causes the date/time to become unreliable so it's better
to wait until we have some sort of reception.

This invalidates #2 and closes #5.

It turned out that some (?) receivers use an old timestamp in at least GGA when they
do not have a position. This causes the date/time to become unreliable so it's better
to wait until we have some sort of reception.

This invalidates #2 and closes mikalhart#5.
@stilldavid
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I'm not the repo owner, but I'm going to point out that some receivers (like the Adafruit Ultimate GPS) have a built-in RTC with a battery backup. I'm using one as a time source, and it's nice to be able to pull the time without requiring a location fix. In this case, the time will still be valid even without a position fix, which I consider a feature and not a bug.

@AlyssonRowan
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While my GPS continues to produce valid timestamps,it does not include a
date.

I agree that this is definitely a feature, but the RTC in my (inexpensive)
GPS does tend to drift rather more than the DS3231 RTC that I have
installed on my arduino.

I am currently working on a navigational app whereby the built in RTC is
updated occasionally (top of the hour - ish) when there is a fix from the
GPS, and the display time is fed from the RTC rather than the GPS.

On 14 February 2016 at 17:32, David Stillman [email protected]
wrote:

I'm not the repo owner, but I'm going to point out that some receivers
(like the Adafruit Ultimate GPS) have a built-in RTC with a battery backup.
I'm using one as a time source, and it's nice to be able to pull the time
without requiring a location fix. In this case, the time will still be
valid even without a position fix, which I consider a feature and not a bug.


Reply to this email directly or view it on GitHub
#6 (comment).

@mikalhart
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I think the comments from @stilldavid and @AlyssonRowan have convinced me to leave this as is for now.

@mikalhart mikalhart closed this Apr 14, 2017
slippyr4 added a commit to slippyr4/TinyGPSPlus that referenced this pull request Jan 11, 2018
add support for fix mode (RMC mikalhart#12) (NMEA 2.3+)
@mikalhart mikalhart mentioned this pull request Oct 12, 2019
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Successfully merging this pull request may close these issues.

Time/Date sometimes erroneously reported as "valid"/"updated"
4 participants