On 07/28/2017 02:01 AM, Attila Kinali wrote:
On Thu, 27 Jul 2017 17:49:14 -0500
Didier Juges <> wrote:

I cannot imagine a work around since the problem stems from the GPS service
only identifying the current date within a particular 1024 weeks epoch
unless the government changes the amount of data that is sent over the GPS
system. Somebody has to use other method to determine the epoch and add the
corresponding offset.

There is: There is a 13bit week number in message type 10. This gives
a 157 year span instead of the ~19 years of the 10bit week number.
This has been part of the GPS standard since IS-GPS-200D which was
released in 2004. As such I am a little bit surprised that the u-blox
receivers still don't support this message (the LEA-5 family was released
in 2007 IIRC). But you can use the UBX RXM-SFRBX  messages to get the
raw GPS messages and decode them yourself.

Yes, but it is only relevant if you to L2C, on which CNAV is encoded. As far as I have seen, there is no support in the L1 C/A NAV, also known as LNAV, message for anything but 10 bit GPS-week numbers, which brings back the topic.

Now, there is a reason I advocate for L2C and L5 capable receivers, this is one of them.

Don't blame receiver vendors for not using L2C CNAV messages when they only do L1 C/A receivers.

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