Factory GPS Pet Theory (Slow to lock up)

I've been spending alot of time lately gathering stuff to sell and noticed one of my machines that has been idle (turned off, main batteries dead) was not locking up on the constellatons as quickly as it had before. I watched it closely a few days ago and it took 3-4 hours to finally sync. On a hunch I checked the battery backup on the GPS itself and it was dead. I replaced it and after locking up again, turned it off. I turned it on this afternoon and it sync'd up within 30 seconds. I know this is perfectly sensible and logical but I'd overlooked it before. I just wish we could get our hands on the gps chip manual as I know there are alot of important things we could be doing to make them function better (internal commands to force a reset, or force SPECIFIC channels on power cycle) using serial command line interface but I've searched for a few years now without any luck.

Just a random utterance.

Me.

 

Does this help you? I've had a copy of this for years...

http://www.buytough.com/tb_pdf/GPS_Spec_CF-18-29.pdf

 

No, it's a different chip, and the datasheet doesn't give enough information either. For instance the newer chip is 12 channels, vs. the 8 channel Matsua one in the factory module. What a rip off Those folks with factory gps in their cf-29's need to grab themselves the actual "developer" manual for these.

 

You have struck a cord with me here. I noticed the same with my Aftermarket GPS, now takes for ever to lock. I will have to see if there is a battery to check out.
Rick H...

 

I've never had an issue with the EM-408 locking on unless the antenna has been damaged. I also have never really had an issue with the GPS in the CF-29. Granted... It is not as good as the EM-408 coupled with a good active GPS antenna... But it is still miles ahead of the stock GPS on the CF-28. Personally I think it has to do with the ground plane (or lack of one) on the CF-28. I posted in another thread that I added a ground plane to the stock GPS setup on a CF-28 and actually achieved very good results. About on par with the CF-29... 5-7 sats regularly. I tried adding the active patch antenna to the CF-28 and couldn't get it to work. Something in the plastic ports covers stopped the signal. It wasn't transparent to the GPS signal and was a major failure. Adding the Sarantel to the RIM location is the way to go. But then is the only weak spot on an otherwise indestructible laptop.

 

Trust me, you do not want to be able to do any of those things. Depending on the gps receiver and the software you are using to see it, it is what it is. Your GPS receives signals from a greater or lesser number of satellites depending on its capacity. The location it gives you is an average of hundreds to thousands of individual data strings. There is no way you could evaluate those strings and decide which ones you wanted to use. There are many variables which determine which satellites your GPS uses to report position and which ones it throws out. Depending on the sophistication of your receiver (not necessarily its cost) your accuracy is based on its ability to correctly dither the data. You might need to adjust the baud rate or the output protocol, but the rest of the settings in your average GPS are built in and beyond the control of the operator.
CAP

 

I'm a little unclear on all the postings about the stock GPS in a -29:
Is a there a battery back up?
Is the stock antenna an active antenna or a passive antenna?

Mine is so flukey its hard to figure out, its works fine one minute and won't work the next. I tried taking it out and stroking it, but that didn't help any.