"Low signal from GPS" message criteria

**parksgm** · 10-10-2007, 02:47 PM

As I am driving, I've recently noticed that SD is dimming the Nav screen and displaying "low signal from GPS" intermittently while I'm in motion. The message usually goes away after 1-5 seconds, but then returns at varying intervals. Sometimes, it returns in 3-4 seconds, while at other times, there will be a 3 to 4 minute interval. The GPS digimod shows that the receiver is seeing at least three satellites when the message appears. When the message is not there, Nav works as expected.

I've never had this problem before, and I have not moved my GPS receiver.

So, what causes the "low signal from GPS" message to be triggered within SD? Could I have a COM port problem of some sort that is preventing constant data transmission from the receiver (this doesn't seem likely, but I can't think of many other explanations).

**DarquePervert** · 10-10-2007, 03:16 PM

I believe this message comes down when you don't have a lock to three or more satellites.

**parksgm** · 10-10-2007, 07:17 PM

Originally Posted by DarquePervert

I believe this message comes down when you don't have a lock to three or more satellites.

Yeah...it's weird that it just started popping up. I haven't changed anything with regard to the GPS receiver positioning or software. I did rearrange some COM ports after I installed a BT dongle, but if something were screwed up there I would think the GPS would just not work rather than give an intermittent low signal state.

**barry0164** · 10-20-2007, 07:19 AM

I have the same issue.
Cant' trust on this navigation always stops when you need it most or wont even bother starting at all.
gps mouse is in the same position - in fornt of windscreen- as where I put my (stand alone)TomTom gps. (yes, tom tom: this at least works 100%)

**jayearl** · 10-22-2007, 06:53 PM

I was constantly getting "Low signal from GPS" warning message displayed. Same results using BU-353 or Garmin GPS18 with Spanner. Typically I have 6+ satellites in lock when driving out in the open, and it SD still does this. In my setup SD also quits updating the map for 15-20 seconds then makes huge jumps when it decides to update again.

I gave up on SD/mappoint and now use NRoute run as an external app from SD. The street or topo maps update smoothly, accurately, and never drop out.

I think it is a SD software issue when it reads the com port gps data stream. None of my other GPS applications (NRoute/TOPO/City Navigator, S&T) behave the way SD/mappoint does with my two GPS receivers.

**parksgm** · 10-23-2007, 06:11 AM

Originally Posted by jayearl

I was constantly getting "Low signal from GPS" warning message displayed. Same results using BU-353 or Garmin GPS18 with Spanner. Typically I have 6+ satellites in lock when driving out in the open, and it SD still does this. In my setup SD also quits updating the map for 15-20 seconds then makes huge jumps when it decides to update again.

I gave up on SD/mappoint and now use NRoute run as an external app from SD. The street or topo maps update smoothly, accurately, and never drop out.

I think it is a SD software issue when it reads the com port gps data stream. None of my other GPS applications (NRoute/TOPO/City Navigator, S&T) behave the way SD/mappoint does with my two GPS receivers.

That's very helpful information, as it will keep me from hunting for whatever I might have been doing wrong.

The odd thing is though, that this behavior just started with my install. I added a bluetooth dongle, which involved rearranging some COM ports, and I _think_ I begin to have problems after that install. I'll check my port settings, and see if any baud rates are inconsistent/unmatched.