GPS Week Number Rollover [WNRO] JUST Findings, Fixes, and Frustrations

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That's exactly why I asked you the question :-). So you can test the solution proposed by treysis on the Digital Elteboard website ("GPS Wochennummern werden zurückgesetzt! Achtung!", Page 13, post # 185).

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Exactly. ingsvcd is outputting to gpspipe2, I'm reading from there, converting the date, writing correct NMEA sentence back to gpspipe. Obviously there are some rather complicated steps involved in this and there's also a checksum.

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Yes. It's called "LD_PRELOAD". Works only for binaries with dynamically linked libraries. Thankfully that's the case on TomTom. With LD_PRELOAD you can exchange the function in the binary with a function from your own library and then do whatever you want (e.g. change the file handle). This was new to me as well, just learned about it.

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True true. But computers sometimes are generous, aren't they? We might be lucky: the file name of the named pipe is indeed hardcoded into gltt, but that also means you can just change the string in the binary, as long as you don't change the length
Yes, initially I wanted to provide an example using LD_PRELOAD to overwrite the fdopen-function used by gltt and to change the output filename. Or even better, just intercept the data that gltt is writing into the named pipe and adjust it on the go. But I was too lazy now and the hex editor option seems sooo much simpler that I prefer to go this way first.

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While this is not easy, it's also not too difficult. It's actually quite a good task for someone to learn programming. However, Google also provides enough examples on how to do this. It was actually much more difficult (for me) to extract the date from the sentences and to transform it.
Next task: write a routine that stores the current date. If it detects next time that the current date is before the recorded date, it means we encountered the next WNRO event in 2038. Should I make it future proof or dodge the bullet like TomTom and just hope nobody is using any GL1 device anymore by 2038
Oh, and maybe they will fail anyway because of the year 2038 problem...and I don't really wanna try that cause I'm afraid this might hardbrick my TomTom.

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I could do that, but like I said, it would take much more time, even though it might be a cleaner solution. For now I am going with the hex-editing option. I've prepared a fix, someone already tested it, and while there are satellites visible, it doesn't seem to get a fix. I suspect the NMEA sentences for $GPRMC are slightly different for the gltt binary, and I didn't really include much error checking in my original converter.
If you can help me out with some logged sentences from your GL1 device? Maybe some with, and some without satellite fix?

@treysis: how can we help? can you send the files here and instructions in english? thanks.

hi,

I test curious case

I found some peopel said put old ephem files, so in navcore 9.702 I put ephem files from 2010 and fist time turn on satnat gps works, i turn off and turn on and never works more but I saw it have last location memorized so I make reset, when turn on signal works again

So if I reset all time turn off/on works

not is solution but is curious situation

hi test without ephem files and same situation, works after reset

Install MiniLog (

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), it will record a logfile to MiniLog-dir. Send this log to me.

Beware: this contains your location. I promise I will treat it confidential and scramble it immediately and delete the original file.

Thx to the help of @NicocoLecha I think I found the solution!

Ok, reports from some users suggest my fix for GL1 devices seems to be working. No need to care for QuickGPS as well. Not sure if GL1 devices even use this.