On 09/02/14 23:24, d0ct0r wrote:
I found the document about Trimble ACE3 module:
http://www.symres.com/files/ACE3.pdf
Here is the paragraph about WNRO:
====================================================
Effect of GPS Week Number Roll-over (WNRO)
The ACE III GPS module has been designed to handle WNRO, and there are
no problems
with either dates or first fix after WNRO through the year 2015.
[* Note – GPS Week Numbers system, as defined by the ICD200 GPS
Specification, occupy
a range from zero to 1023. The Week Number Roll Over (WNRO) occurs every
1024
weeks, or approximately every 19 years 8 months. August 1999 was the
first roll-over for
the GPS system since the beginning of GPS time on 06 January 1980.]
First GPS week of 2016 is GPS week of 1878.
Which gives indication wrap-around and also means it has been valid
since mid 1996.
[ Caution – Trimble OEM GPS receivers have reported the true GPS Week
Number in TSIP
messages 0x41 and 0x8F-20 as a number between 0 and 1023. The ACE III
GPS outputs
the Extended GPS Week Number as the absolute number of weeks since the
beginning of
GPS time or 06 January 1980. If the true GPS Week Number is desired, the
system
developer should ignore the extra MSBs of the Extended GPS Week Number
and use only
the 10 LSBs]
If you don't listen to the Extended GPS Week Number, you are toast, but
as there is an end to the Ace III extension capability, there isn't far
away and you are toast anyway.
====================================================
I tried to modify the "demo" code to obtain FW of my GPS module. But I
had no luck with it, since
"bcGPSMan" subroutine always return ERROR state in response to packet ID
0x1F.
I think this is another case where the developers didn't forsee this
situation.
Cheers,
Magnus
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