dragonsteve
Posts: 16
Joined: Thu Sep 15, 2005 3:50 pm

Map stuck, or so it seems

Wed Feb 08, 2006 5:38 pm

Hi,

how is it possible to get a GpsFix from the parser when there are no satellites that can be used for fix?
In my software that I make I check the gpsFix that I get from the parser to let the rest of my program function correctly.

From time to time my map got stuck.
No more movement, even after a while waiting.

When the satellites are giving UsedForFix = false and then you ask the getGpsFix from the parser you get a valid fix.
Normally this can't be possible because you don't have any satellites.
So the object should be returning nothing, or at least the parameters should be reset so it is possible to check them.

Am I correct in my assumption?

I always was assuming that if I don't get a fix my program shouldn't work, but no I have to change it.
If I , after first initialisation fix, don't get a UseForFix from the satellites then I have to dispose my GPS parser object and reconnect it.

User avatar
johan
GpsGate
Posts: 15342
Joined: Wed Aug 04, 2004 10:40 pm
Location: Sweden
Contact: Website

RE: Map stuck, or so it seems

Wed Feb 08, 2006 5:50 pm

When the GPS had a valid position fix and has now lost track of satellites by for example being under a roof. A GpsFix object is returned with last known Position, and UTC is set to the time when this last Position was determined.
ComStatus.ValidNmea is true.
ComStatus.ValidFix is false.

This means you can detect this state by checking GpsFix.UTC or ComStatus.ValidFix

The reference manual is a great source of information. PLease read more about NmeaParser.GetGpsFix() here:
http://franson.com/gpstools/reference_manual.asp?comp=tools&class=NmeaParser&item=GetGpsFix&platform=net

Regards,
Johan

Franson Support

dragonsteve
Posts: 16
Joined: Thu Sep 15, 2005 3:50 pm

RE: Map stuck, or so it seems

Wed Feb 08, 2006 6:02 pm

Ok, thanks Johan for that explanation.

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