I'm looking for an algorithm for converting the current date/time to
the 2 value system used by GPS of week number and time of week.

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Request for Question Clarification by wonko-ga on 02 Jul 2003 11:41 PDT

Would one of these links be a sufficient answer: 
 
http://www.ngs.noaa.gov/gps-toolbox/bwr-c.txt 
 
http://www.ngs.noaa.gov/gps-toolbox/bwr-f.txt 
 
Accessed from "The GPS Toolbox":  http://www.ngs.noaa.gov/gps-toolbox/index.html 
 
Thanks! 

Wonko

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Clarification of Question by chiporange-ga on 02 Jul 2003 14:37 PDT

No, I'm sorry, but an uncommented code fragment with no explanation
(and I'm afraid, in a computer language that I don't know) won't help
me.  I really need a textual description, or perhaps a code fragment
with sufficient documentation so that I could follow what was going
on.  These fragments also have no provision for converting local time
to UTC time, which is necessary as part of the solution.

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Clarification of Question by chiporange-ga on 03 Jul 2003 05:15 PDT

I need to send an initialization string to a SiRFStar GPS receiver
using the $PSRF104 NMEA command; I *believe* I need, for this
initialization, the current time express as "time of week" and "week
number" (terms meaningful to GPS).  I *believe* that this means first,
translating local time into UTC, then, translating UTC into the date
into the number of weeks since Aug 22, 1999, and the number of seconds
elapsed in the current week (and then the correction for leap seconds
added to the result).  I *need* these assumptions confirmed as much as
I need the algorithm itself.

I need the question answered as to whether I should add the 1024 value
to the week number to compensate for the week number roll-over that
occurred on August 22, 1999, since the original epock was from Jan 6,
1980.
I'm working in Visual FoxPro, but any sufficiently commented code
fragment that looks anything like VB should do (assuming it doesn't
make use of language features not available in other programming
languages (such as a handy-dandy time/date conversion function for the
UTC conversion).

Do you simply want an algorithm for handling the required date
arithmetic?  I.e., the number of days, months, years since January 1,
1901 or January 6, 1980.

Other than this portion, the algorithm would be very simple.  Is there
a programming language that you do understand that you would want the
algorithm written in?

I am not a researcher, so I'll give Wonko (and others) a chance to
respond first.
Bradley