Trick to Possibly Fix Colorado's Acquisition Issues!

[Didjerrydo]

After discovering that my new Colorado 300 was seemingly having trouble re-acquiring signal and re-locatoing even after a short (20 mile) trip while it had been turned off, I started talking to Garmin concerning this issue.

I was able to talk to a fellow who actually seemed to know his stuff on the Colorados and told me something very helpful and informative. After explaining the problem to him, he suggested that perhaps the unit had never actually established a thorough almanac to work with. What he suggested was to take the unit outdoors on an open area with an unobstructed view of the sky, and just let it boot up and lay there undisturbed for at least 20 minutes. He emphasized that 20 minutes is the magic number (of course longer is OK too), but that apparently a new unit this in needed to totally get its stuff in a row.

I had never realized this, nor have I ever seen this bit of information in any Garmin product manual in the past.

I have done this procedure and I do believe it has hopefully fixed the problem. You might want to give it a try if you, like myself, have been too busy playing with your new toy to ever let it completely "find itself"!

[+apersson850]

20 minutes is a good estimate. Transmitting the entire almanac data block takes 12.5 minutes. It's split over 25 frames, each 30 seconds long. Each frame is split in five subframes. The first three subframes are specific for the transmitting satellite, as they contain clock correction and ephemeris data for that particular SV. The last two contain almanac data, which repeats every 12.5 minutes, as stated above.

 

If all almanac data is transmitted before the 12.5 minute cycle has ended, it starts over again. Hence 20 minutes is a good estimate of the time required to make reasonably sure that the reeiver has been able to listen to all frames once, and to most of them twice.

 

Further reading.

Edited January 29, 2008 by apersson850

[Didjerrydo]

20 minutes is a good estimate. Transmitting the entire almanac data block takes 12.5 minutes. It's split over 25 frames, each 30 seconds long. Each frame is split in five subframes. The first three subframes are specific for the transmitting satellite, as they contain clock correction and ephemeris data for that particular SV. The last two contain almanac data, which repeats every 12.5 minutes, as stated above.

 

If all almanac data is transmitted before the 12.5 minute cycle has ended, it starts over again. Hence 20 minutes is a good estimate of the time required to make reasonably sure that the reeiver has been able to listen to all frames once, and to most of them twice.

 

Further reading.

That's interesting, looks like GPS manufacturers would tell owners that they should let them lay somewhere undisturbed and do this data "soak up" to get them properly set up to acquire properly!

[+apersson850]

Normally this happens by itself, as most people will use their GPS more than 20 minutes at a time.

[+Geocaching-Geckos]

Hmm, I will have to try leave my Colorado unit on a little longer next time. I know I have made a couple of 20-30 minute trips with it last week and I'm still having an acquisition issue.

 

I'll let it do a data "soak up" and let you know if it resolves the problem.

Edited January 29, 2008 by Geocaching-Geckos

[Didjerrydo]

Normally this happens by itself, as most people will use their GPS more than 20 minutes at a time.

 

Well, I thought I had fixed the issue, but it's starting again. I also am noticing that when this occurs, the internal clock is way off (15 minutes slow). I'm afraid that this unit has some other more serious problems?